MOTOROLA MC68HC11G5CFN

MC68HC11G5/D
MC68HC11G5
HC11
TECHNICAL DATA
MC68HC11G5
MC68HC11G7
MC68HC711G5
TECHNICAL
DATA
MC68HC11G5
MC68HC11G7
MC68HC711G5
High-density Complementary Metal Oxide
Semiconductor (HCMOS) Microcontroller
Unit
Motorola reserves the right to make changes without further notice to any products herein to improve reliability, function or design.
Motorola does not assume any liability arising out of the application or use of any product or circuit described herein; neither does
it convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized
for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain
life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death
may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall
indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs,
damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design
or manufacture of the part. Motorola and
are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/
Affirmative Action Employer.
© MOTOROLA LTD., 1991
TABLE OF CONTENTS (Continued)
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Number
Page
Number
Title
TABLE OF CONTENTS
Paragraph
Number
Page
Number
Title
Section 1
Introduction
1.1
1.2
General ........................................................................................................
Features of the Motorola MC68HC11G5 MCU ............................................
1-1
1-1
Section 2
Operating Modes and Signal Description
2.1
2.1.1
2.1.2
2.1.3
2.1.4
2.1.4.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
2.2.9
2.2.10
2.2.11
Operating Modes .........................................................................................
Single Chip Operating Mode ..................................................................
Expanded Non-Multiplexed Operating Mode .........................................
Bootstrap Operating Mode .....................................................................
Test Operating Mode ..............................................................................
Factory Test Register (TEST1) .........................................................
Signal Description ........................................................................................
Input Power (VDD) and Ground (VSS) ...................................................
Reset (RESET) .......................................................................................
Crystal Driver (XTAL) and External Clock Input (EXTAL) ......................
E-clock Output (E) ..................................................................................
Read/Write (R/W) ...................................................................................
Interrupt Request (IRQ) ..........................................................................
Non-Maskable Interrupt (XIRQ) ..............................................................
Halt (HALT) ............................................................................................
Mode A/Load Instruction Register (MODA/LIR) and Mode B/Standby
Voltage (MODB/Vkam) ...........................................................................
A/D Converter Reference Voltages (Vrl, Vrh) .........................................
Port Signals ............................................................................................
MC68HC11G5
2-1
2-2
2-2
2-2
2-2
2-4
2-5
2-5
2-6
2-7
2-7
2-7
2-7
2-7
2-7
2-8
2-8
2-8
MOTOROLA
i
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
Section 3
Memory and Control/Status Registers
3.1
3.2
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5
3.5.1
3.5.2
3.6
ROM .............................................................................................................
Bootstrap ROM ............................................................................................
RAM .............................................................................................................
Memory Map ................................................................................................
Single Chip Mode ...................................................................................
Expanded Non-multiplexed Mode ..........................................................
Special Bootstrap Mode .........................................................................
Special Test Mode ..................................................................................
Changing Modes ....................................................................................
System Configuration ...................................................................................
RAM and I/O Mapping Register (INIT) ...................................................
Configuration Control Register (CONFIG) ..............................................
Control/Status Registers ..............................................................................
3-1
3-1
3-1
3-2
3-2
3-3
3-4
3-4
3-4
3-4
3-5
3-6
3-6
Section 4
Input/Output Ports
4.1
4.2
4.3
4.4
4.4.1
4.4.2
4.5
4.5.1
4.6
4.6.1
4.6.2
4.7
4.7.1
4.7.2
4.8
4.8.1
4.9
4.9.1
Mode Dependencies ....................................................................................
General Purpose I/O (Ports A, C, D, G, H, and J) .......................................
Fixed Direction I/O (Ports B, E, and F) ........................................................
Port A ...........................................................................................................
Data Register (PORTA ) .........................................................................
Data Direction Register (DDRA ) ............................................................
Port B ...........................................................................................................
Data Register (PORTB) ..........................................................................
Port C ...........................................................................................................
Data Register (PORTC) .........................................................................
Data Direction Register (DDRC) ............................................................
Port D ...........................................................................................................
Data Register (PORTD) .........................................................................
Data Direction Register (DDRD) ............................................................
Port E ...........................................................................................................
Data Register (PORTE) ..........................................................................
Port F ...........................................................................................................
Data Register (PORTF) ..........................................................................
MOTOROLA
ii
4-1
4-2
4-2
4-2
4-3
4-3
4-4
4-4
4-4
4-5
4-5
4-5
4-6
4-6
4-7
4-7
4-8
4-8
MC68HC11G5
TABLE OF CONTENTS (Continued)
Paragraph
Number
4.10
4.10.1
4.10.2
4.11
4.11.1
4.11.2
4.12
4.12.1
4.12.2
4.13
4.13.1
4.13.2
4.13.3
Page
Number
Title
Port G ...........................................................................................................
Data Register (PORTG) .........................................................................
Data Direction Register (DDRG) ............................................................
Port H ...........................................................................................................
Data Register (PORTH) .........................................................................
Data Direction Register (DDRH) ............................................................
Port J ............................................................................................................
Data Register (PORTJ) .........................................................................
Data Direction Register (DDRJ) ............................................................
Expanded Bus (Ports B, C, F) ......................................................................
R/W ........................................................................................................
Memory Ready (MRDY) .........................................................................
Options Register 2 (OPT2) .....................................................................
4-8
4-9
4-9
4-9
4-10
4-10
4-11
4-11
4-11
4-12
4-12
4-13
4-13
Section 5
Resets, Interrupts and Low Power Modes
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.2.6
5.2.7
5.3
5.3.1
5.3.2
Resets ..........................................................................................................
RESET Pin .............................................................................................
Power-on-reset (POR) ............................................................................
Computer Operating Properly (COP) Reset ...........................................
Clock Monitor Reset ...............................................................................
Configuration Options Register (OPTION) .............................................
State After Reset ....................................................................................
Interrupts ......................................................................................................
Interrupt Vector Assignments .................................................................
Software Interrupt (SWI) .........................................................................
Illegal Opcode Trap ................................................................................
Real Time Interrupt .................................................................................
Interrupt Mask Bits in Condition Code Register .....................................
Priority and Masking Structure ...............................................................
“Highest Priority I” Interrupt and Miscellaneous Register (HPRIO) ........
Low Power Modes .......................................................................................
WAIT ......................................................................................................
STOP ......................................................................................................
MC68HC11G5
5-1
5-1
5-1
5-2
5-2
5-3
5-4
5-6
5-6
5-8
5-8
5-8
5-9
5-9
5-15
5-17
5-17
5-17
MOTOROLA
iii
TABLE OF CONTENTS (Continued)
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Number
Page
Number
Title
Section 6
Programmable Timer, Real Time Interrupt and Pulse Accumulator
6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
6.2
6.3
6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
6.4.7
6.4.8
6.4.9
6.4.10
6.4.11
6.4.12
6.4.13
6.4.14
6.4.15
6.4.16
6.4.17
6.4.18
6.4.19
6.4.20
Programmable Timer ...................................................................................
Counters .................................................................................................
Prescalers ..............................................................................................
Input Capture Functions .........................................................................
Output Compare Functions ....................................................................
Programmable Input Capture/Output Compares ....................................
Real Time Interrupt ......................................................................................
Pulse Accumulator .......................................................................................
Timer, RTI and Pulse Accumulator Registers ..............................................
Count Registers (TCNT1 and TCNT2) ...................................................
Prescaler Register (TPRE) .....................................................................
Input Capture Registers (TIC1 – TIC3) ..................................................
Output Compare Registers (TOC1 – TOC4) ..........................................
Output Compare 5/Input Capture 4 Register (TO5I4) ............................
Output Compare 6/Input Capture 5 Register (TO6I5) ............................
Output Compare 7/Input Capture 6 Register (TO7I6) ............................
Output Compare 1 Action Mask Register (OC1M) .................................
Output Compare 1 Action Data Register (OC1D) ..................................
Compare Force Register (CFORC) ........................................................
Control Register 1 (TCTL1) ....................................................................
Timer Control Register 2 (TCTL2) ..........................................................
Timer Control Register 3 (TCTL3) ..........................................................
Control Register 4 (TCTL4) ....................................................................
Main Timer Interrupt Mask Register 1 (TMSK1) .....................................
Main Timer Interrupt Flag Register 1 (TFLG1) .......................................
Miscellaneous Timer Interrupt Mask Register 2 (TMSK2) ......................
Miscellaneous Timer Interrupt Flag Register 2 (TFLG2) ........................
Count Register (PACNT) ........................................................................
Pulse Accumulator Control Register (PACTL) .......................................
MOTOROLA
iv
6-1
6-1
6-2
6-2
6-2
6-3
6-4
6-4
6-5
6-5
6-6
6-7
6-8
6-9
6-9
6-10
6-10
6-11
6-11
6-12
6-12
6-13
6-14
6-15
6-15
6-16
6-17
6-18
6-19
MC68HC11G5
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
Section 7
Serial Communications Interface
7.1
7.1.1
7.1.2
7.1.3
7.2
7.3
7.4
7.4.1
7.4.2
7.5
7.6
7.7
7.8
7.8.1
7.8.2
7.8.3
7.8.4
7.8.5
Overview and Features ................................................................................
SCI Two-wire System Features: .............................................................
SCI Receiver Features ...........................................................................
SCI Transmitter Features .......................................................................
Functional Description .................................................................................
Data Format .................................................................................................
Receiver Wake-up Operation .......................................................................
Idle Line Wake-up ..................................................................................
Address Mark Wake-up ..........................................................................
Receive Data (RXD) .....................................................................................
Start Bit Detection ........................................................................................
Transmit Data (TXD) ....................................................................................
SCI Registers ...............................................................................................
Serial Communications Data Register (SCDAT) ....................................
Serial Communications Control Register 1 (SCCR1) .............................
Serial Communications Control Register 2 (SCCR2) .............................
Serial Communications Status Register (SCSR) ...................................
Baud Rate Register (BAUD) ...................................................................
7-1
7-1
7-1
7-2
7-2
7-4
7-4
7-5
7-5
7-5
7-6
7-8
7-8
7-8
7-8
7-9
7-11
7-12
Section 8
Serial Peripheral Interface
8.1
8.2
8.2.1
8.2.2
8.2.3
8.2.4
8.3
8.4
8.4.1
8.4.2
8.4.3
Overview and Features ................................................................................
SPI Signal Descriptions ...............................................................................
Master In Slave Out (MISO) ...................................................................
Master Out Slave In (MOSI) ...................................................................
Serial Clock (SCK) .................................................................................
Slave Select (SS) ...................................................................................
Functional Description .................................................................................
SPI Registers ...............................................................................................
Control Register (SPCR) ........................................................................
Status Register (SPSR) ..........................................................................
Data I/O Register (SPDAT) ....................................................................
MC68HC11G5
8-1
8-1
8-2
8-2
8-2
8-3
8-4
8-5
8-5
8-7
8-8
MOTOROLA
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TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
Section 9
Analog-to-Digital Converter
9.1
9.2
9.3
9.3.1
9.3.2
9.3.3
9.3.4
9.4
9.4.1
9.4.2
9.4.3
9.4.4
9.5
9.6
9.7
9.7.1
9.7.2
Conversion Process .....................................................................................
Channel Assignments ..................................................................................
Single Channel Operation ............................................................................
4-Conversion, Single Scan .....................................................................
4-Conversion, Continuous Scan .............................................................
8-Conversion, Single Scan .....................................................................
8-Conversion, Continuous Scan .............................................................
Multiple Channel Operation .........................................................................
4-Channel Single Scan ...........................................................................
4-Channel Continuous Scan ..................................................................
8-Channel Single Scan ...........................................................................
8-Channel Continuous Scan ..................................................................
Power-up and Clock Select ..........................................................................
Operation in STOP and WAIT Modes ..........................................................
Registers ......................................................................................................
A/D Control and Status Register (ADCTL) .............................................
Result Registers (ADR1 – ADR8) ..........................................................
9-2
9-2
9-3
9-3
9-3
9-4
9-4
9-4
9-4
9-4
9-4
9-5
9-5
9-5
9-6
9-6
9-7
Section 10
Pulse Width Modulation Timer
10.1
10.2
10.3
10.4
10.5
10.5.1
10.5.2
10.5.3
10.5.4
10.5.5
10.5.6
10.5.7
General Overview ........................................................................................
Clock Selection ............................................................................................
16-bit PWM Function ...................................................................................
Boundary Cases ..........................................................................................
PWM Registers ............................................................................................
Counter Registers (PWCNTx) ................................................................
Period Registers (PWPERx) ..................................................................
Duty Registers (PWDTYx) ......................................................................
Clock Select Register (PWCLK) .............................................................
Polarity Select Register (PWPOL) ..........................................................
Scale Register (PWSCAL) .....................................................................
Enable Register (PWEN) ........................................................................
MOTOROLA
vi
10-1
10-3
10-3
10-4
10-4
10-4
10-5
10-5
10-6
10-8
10-9
10-10
MC68HC11G5
TABLE OF CONTENTS (Continued)
Paragraph
Number
Page
Number
Title
Section 11
Event Counter
11.1
11.2
11.2.1
11.2.2
11.2.2.1
11.2.2.2
11.2.2.3
11.2.2.4
11.2.2.5
11.2.2.6
11.2.2.7
11.2.2.8
11.2.2.9
11.3
11.3.1
11.3.2
11.3.3
11.3.3.1
11.3.3.2
11.3.3.3
11.3.3.4
11.3.3.5
11.3.3.6
11.3.3.7
11.3.3.8
11.3.3.9
11.4
11.4.1
11.4.2
11.4.3
11.4.3.1
11.4.3.2
11.4.3.3
11.4.3.4
11.4.3.5
11.4.3.6
11.4.3.7
11.4.3.8
11.4.3.9
Introduction ..................................................................................................
Mode 0: 8-bit PWM with Selectable Phase Shift ..........................................
Operation of PWM and PA Unit in Mode 0 .............................................
Register Functions in Mode 0 .................................................................
Counter 1 (EVCNT1) ........................................................................
Compare Register 1A (ECMP1A); (Y) ..............................................
Compare Register 1B (ECMP1B); (X’) .............................................
Counter 2 (EVCNT2) ........................................................................
Compare Register 2A (ECMP2A); (X) ..............................................
Compare Register 2B (ECMP2B) .....................................................
Input Unit 1 (EVI1) ............................................................................
Input Unit 2 (EVI2) ............................................................................
Output Unit (EVO) .............................................................................
Mode 1: 8-bit PWM and Pulse Accumulator ................................................
Operation of Pulse Width Modulation Unit in Mode 1 .............................
Operation of Pulse Accumulator Unit in Mode 1 ....................................
Register Functions in Mode 1 .................................................................
Counter 1 (EVCNT1) ........................................................................
Compare Register 1A (ECMP1A) .....................................................
Compare Register 1B (ECMP1B) .....................................................
Counter 2 (EVCNT2) ........................................................................
Compare Register 2A (ECMP2A) .....................................................
Compare Register 2B (ECMP2B) .....................................................
Input Unit 1 (EVI1) ............................................................................
Input Unit 2 (EVI2) ............................................................................
Output Unit (EVO) .............................................................................
Mode 2: 8-bit PWM with Period Counter ......................................................
Operation of Pulse Width Modulation Unit in Mode 2 .............................
Operation of Pulse Accumulator Unit in Mode 2 ....................................
Register Functions in Mode 2 .................................................................
Counter 1 (EVCNT1) ........................................................................
Compare Register 1A (ECMP1A) .....................................................
Compare Register 1B (ECMP1B) .....................................................
Counter 2 (EVCNT2) ........................................................................
Compare Register 2A (ECMP2A) .....................................................
Compare Register 2B (ECMP2B) .....................................................
Input Unit 1 (EVI1) ............................................................................
Input Unit 2 (EVI2) ............................................................................
Output Unit (EVO) .............................................................................
MC68HC11G5
11-1
11-3
11-3
11-4
11-4
11-4
11-4
11-5
11-5
11-5
11-5
11-5
11-5
11-6
11-7
11-7
11-7
11-7
11-8
11-8
11-8
11-8
11-8
11-8
11-8
11-9
11-9
11-10
11-10
11-10
11-10
11-11
11-11
11-11
11-11
11-11
11-11
11-11
11-11
MOTOROLA
vii
TABLE OF CONTENTS (Continued)
Paragraph
Number
11.5
11.5.1
11.5.2
11.5.3
11.5.3.1
11.5.3.2
11.5.3.3
11.5.3.4
11.5.3.5
11.5.3.6
11.5.3.7
11.5.3.8
11.5.3.9
11.6
11.6.1
11.6.2
11.6.3
11.6.4
11.6.5
11.6.6
11.7
11.8
11.9
Page
Number
Title
Mode 3: 8-bit PWM with 256 Clock Prescaler ..............................................
Operation of Pulse Width Modulation Unit in Mode 3 .............................
Operation of Pulse Accumulator Unit in Mode 3 ....................................
Register Functions in Mode 3 .................................................................
Counter 1 (EVCNT1) ........................................................................
Compare Register 1A (ECMP1A) .....................................................
Compare Register 1B (ECMP1B) .....................................................
Counter 2 (EVCNT2) ........................................................................
Compare Register 2A (ECMP2A) .....................................................
Compare Register 2B (ECMP2B) .....................................................
Input Unit 1 (EVI1) ............................................................................
Input Unit 2 (EVI2) ............................................................................
Output Unit (EVO) .............................................................................
Event Counter Registers ..............................................................................
Counter Clock Register (EVCLK) ...........................................................
Counter Control Register (EVCTL) .........................................................
Counters Enable/Interrupt Mask Register (EVMSK) ..............................
Interrupt Flag Register (EVFLG) ............................................................
Counter Registers (EVCNTx) .................................................................
Counter Compare Registers (ECMPx) ...................................................
PWM using the Event Counter .....................................................................
Effective Range of the Set Up Values ..........................................................
Boundary Conditions of the PWM Function .................................................
11-12
11-12
11-13
11-14
11-14
11-14
11-14
11-14
11-14
11-14
11-14
11-15
11-15
11-15
11-15
11-16
11-17
11-18
11-18
11-19
11-19
11-19
11-20
Section 12
CPU, Addressing Modes and Instruction Set
12.1
12.1.1
12.1.2
12.1.3
12.1.4
12.1.5
12.1.6
12.2
12.2.1
12.2.2
12.2.3
12.2.4
12.2.5
12.2.6
Programming Model and CPU Registers .....................................................
Accumulators A and B ............................................................................
Index Register X (IX) ..............................................................................
Index Register Y (IY) ..............................................................................
Stack Pointer (SP) ..................................................................................
Program Counter (PC) ...........................................................................
Condition Code Register (CCR) .............................................................
Addressing Modes .......................................................................................
Immediate Addressing (IMM) .................................................................
Direct Addressing (DIR) .........................................................................
Extended Addressing (EXT) ...................................................................
Indexed Addressing (IND, X; IND, Y) .....................................................
Inherent Addressing (INH) ......................................................................
Relative Addressing (REL) .....................................................................
MOTOROLA
viii
12-1
12-2
12-2
12-2
12-2
12-2
12-2
12-3
12-3
12-3
12-4
12-4
12-4
12-4
MC68HC11G5
TABLE OF CONTENTS (Continued)
Paragraph
Number
12.3
12.3.1
12.3.1.1
12.3.1.2
12.3.1.3
12.3.1.4
12.3.1.5
12.3.1.6
12.3.2
12.3.3
12.3.4
12.3.4.1
12.3.4.2
12.3.4.3
12.3.4.4
12.3.4.5
Page
Number
Title
Instruction Set ..............................................................................................
Accumulator and Memory Instructions ...................................................
Loads, Stores and Transfers ............................................................
Arithmetic Operations .......................................................................
Multiply and Divide ............................................................................
Logical Operations ............................................................................
Data Testing and Bit Manipulation ....................................................
Shifts and Rotates ............................................................................
Stack and Index Register Instructions ....................................................
Condition Code Register Instructions .....................................................
Program Control Instructions ..................................................................
Branches ...........................................................................................
Jumps ...............................................................................................
Subroutine Calls and Returns (BSR, JSR, RTS) ..............................
Interrupt Handling (RTI, SWI, WAI) ..................................................
Miscellaneous (NOP, STOP, TEST) .................................................
12-4
12-5
12-5
12-6
12-7
12-7
12-8
12-9
12-10
12-11
12-12
12-12
12-14
12-14
12-14
12-15
Section 13
Electrical Specifications
13.1
13.2
13.3
13.4
13.5
13.6
13.7
13.8
13.9
13.10
13.11
Maximum Ratings ........................................................................................
Thermal Characteristics ...............................................................................
Power Considerations ..................................................................................
DC Electrical Characteristics ........................................................................
Control Timing ..............................................................................................
Peripheral Port Characteristics ....................................................................
Timer Characteristics ...................................................................................
A/D Converter Characteristics .....................................................................
Expansion Bus Timing .................................................................................
Serial Peripheral Interface (SPI) Timing ......................................................
Event Counter Characteristics .....................................................................
13-1
13-1
13-2
13-3
13-7
13-12
13-14
13-16
13-17
13-19
13-22
Section 14
Mechanical Data
14.1
14.2
14.3
Ordering Information ....................................................................................
Pin Assignments ..........................................................................................
Package Dimensions ...................................................................................
MC68HC11G5
14-1
14-2
14-3
MOTOROLA
ix
TABLE
TABLE OF
OF CONTENTS
CONTENTS (Concluded)
(Continued)
Paragraph
Number
Page
Number
Title
Appendix A
MC68HC11G7 High-performance MCU with 24 kbyte ROM
Appendix B
MC68HC711G5 High-performance MCU with 16 kbyte EPROM
MOTOROLA
x
MC68HC11G5
LIST
LIST
OFOF
TABLES
ILLUSTRATIONS
(Continued)
Paragraph
Number
1-1
2-1
2-1
2-1
3-1
3-2
3-2
3-2
3-2
5-1
5-2
5-2
5-3
5-3
5-4
7-1
7-2
7-3
7-4
7-5
7-6
7-7
8-1
8-2
8-3
10-1
11-1
11-2
11-3
11-4
11-5
12-1
Page
Number
Title
Functional Block Diagram ............................................................................
Oscillator circuits: (a) External oscillator connections ..................................
Oscillator circuits: (b) One crystal driving two MCUs ...................................
Oscillator circuits: (c) Common crystal connections ....................................
Memory Map ................................................................................................
Control and Status Registers (Page 1) ........................................................
Control and Status Registers (Page 2) ........................................................
Control and Status Registers (Page 3) ........................................................
Control and Status Registers (Page 4) ........................................................
Interrupt Stacking Order ...............................................................................
Processing Flow out of Resets ....................................................................
Processing Flow out of Resets (contd) ........................................................
Interrupt Priority Resolution .........................................................................
Interrupt Priority Resolution (contd) .............................................................
Interrupt Source Resolution within SCI ........................................................
Serial Communications Interface Block Diagram .........................................
Rate Generator Division ...............................................................................
Data Format .................................................................................................
Sampling Technique Used On All Bits .........................................................
Examples of Start Bit Sampling Techniques ................................................
SCI Artificial Start Following a Framing Error ..............................................
SCI Start Bit Following a Break ....................................................................
Data Clock Timing Diagram .........................................................................
Serial Peripheral Interface Block Diagram ...................................................
Serial Peripheral Interface Master-Slave Interconnection ............................
PWM Timer Module Block Diagram .............................................................
Event Counter Operating Modes .................................................................
8-bit PWM with Selectable Phase Shift (Mode 0) ........................................
8-bit PWM and Pulse Accumulator (Mode 1) ...............................................
8-bit PWM with Period Counter (Mode 2) ....................................................
8-bit PWM with 256 Clock Prescaler (Mode 3) ............................................
Programming Model .....................................................................................
MC68HC11G5
1-2
2-6
2-6
2-6
3-3
3-7
3-8
3-9
3-10
5-8
5-10
5-11
5-12
5-13
5-14
7-3
7-4
7-4
7-6
7-7
7-8
7-8
8-2
8-4
8-5
10-2
11-2
11-3
11-6
11-9
11-13
12-2
MOTOROLA
xi
LIST OF ILLUSTRATIONS (Concluded)
Paragraph
Number
13-1
13-2
13-3
13-4
13-5
13-6
13-7
13-8
13-9
13-10
13-11
13-12
13-13
13-14
13-15
13-16
13-17
13-18
13-19
13-20
13-21
13-22
13-23
13-24
A-1
A-2
B-1
B-2
B-3
Page
Number
Title
Test Methods ...............................................................................................
Run IDD vs Bus Frequency (Single Chip Mode – 4.5V, 5.5V) .....................
Run IDD vs Bus Frequency (Expanded Mode – 4.5V, 5.5V) .......................
Wait IDD vs Bus Frequency (Single Chip Mode – 4.5V, 5.5V) ....................
Wait IDD vs Bus Frequency (Expanded Mode – 4.5V, 5.5V) ......................
POR External RESET Timing Diagram ........................................................
STOP Recovery Timing Diagram .................................................................
WAIT Recovery from Interrupt Timing Diagram ...........................................
Interrupt Timing Diagram .............................................................................
Memory Ready Timing Diagram ..................................................................
Entering HALT .............................................................................................
Exiting HALT ................................................................................................
Port Write Timing Diagram ...........................................................................
Port Read Timing Diagram ..........................................................................
Timer Inputs Timing Diagram .......................................................................
Output Compare Timing Diagram ................................................................
Input Capture Timing Diagram .....................................................................
Non-multiplexed Expanded Bus ...................................................................
SPI Master Timing (CPHA = 0) ....................................................................
SPI Master Timing (CPHA = 1) ....................................................................
SPI Slave Timing (CPHA = 0) ......................................................................
SPI Slave Timing (CPHA = 1) ......................................................................
Event Counter Mode 1, 2, 3 – Clock Input Timing Diagram .........................
Event Counter Mode 1, 2, 3 – Clock Gate Input Timing Diagram ................
MC68HC11G7 Functional Block Diagram ...................................................
MC68HC11G7 Memory Map .......................................................................
MC68HC711G5 Functional Block Diagram .................................................
MC68HC711G5 Memory Map .....................................................................
Block Diagram of MC68HC711G5 in PROG Mode ......................................
MOTOROLA
xii
13-4
13-5
13-5
13-6
13-6
13-8
13-8
13-9
13-9
13-10
13-10
13-11
13-12
13-13
13-14
13-15
13-15
13-18
13-20
13-20
13-21
13-21
13-22
13-23
A-1
A-2
B-1
B-2
B-3
MC68HC11G5
LIST OF
LIST
TABLES
OF TABLES
(Continued)
Paragraph
Number
2-1
2-2
2-3
2-3
5-1
5-2
5-3
5-4
6-1
7-1
7-2
8-1
9-1
9-1
12-1
12-2
12-3
12-4
12-5
12-6
12-7
12-8
12-9
12-10
12-11
12-12
13.1
13.2
13.3
B-1
Page
Number
Title
Mode Select Summary .................................................................................
Bootstrap Mode Jump Vectors .....................................................................
Port Signal Functions: (a) Expanded Non-multiplexed and Test Modes .....
Port Signal Functions: (b) Single Chip and Bootstrap Modes ......................
COP Timeout Periods ..................................................................................
Interrupt Vector Masks and Assignments ....................................................
Special Mode Select and Mode Select A Table ...........................................
Priority Select Bits Table ..............................................................................
Real Time Interrupt Rates ............................................................................
First Prescaler Stage ...................................................................................
Second Prescaler Stage ..............................................................................
SPI Rate Selection .......................................................................................
Channel Assignments ..................................................................................
Channel Assignments (continued) ...............................................................
Loads, Stores and Transfers ........................................................................
Arithmetic Operations ..................................................................................
Multiply and Divide .......................................................................................
Logical Operations .......................................................................................
Data Testing and Bit Manipulation ...............................................................
Shifts and Rotates ........................................................................................
Stack And Index Register Instructions .........................................................
Condition Code Register Instructions ..........................................................
Branches ......................................................................................................
Jumps ...........................................................................................................
Subroutine Calls and Returns (BSR, JSR, RTS) .........................................
Interrupt Handling (RTI, SWI, WAI) ..............................................................
Clock Input (Required Limit) ........................................................................
Clock Input (Guaranteed Limit) ....................................................................
Clock Gate Input (Guaranteed Limit) ...........................................................
Operations in PROG Mode ..........................................................................
MC68HC11G5
2-1
2-3
2-9
2-9
5-2
5-7
5-15
5-16
6-20
7-14
7-14
8-7
9-2
9-3
12-5
12-6
12-7
12-7
12-8
12-9
12-10
12-11
12-13
12-14
12-14
12-14
13-22
13-22
13-23
B-4
MOTOROLA
xiii
This page intentionally left blank
MOTOROLA
xiv
MC68HC11G5
SECTION 1
INTRODUCTION
1.1
GENERAL
The MC68HC11G5, which includes 16 kilobytes of on-board ROM, is a member of the M68HC11
family of advanced capability MCUs. This device has 512 bytes of on-board static RAM and a nonmultiplexed expanded bus for accessing external memory.
The original MC68HC11 timer system is expanded to contain 3 input capture ports, 4 output
compare ports and 3 software selectable input capture or output compare ports. A new 4-channel
pulse width modulation timer has been added and there is also an event counter timer system.
The serial I/O system consists of an asynchronous NRZ Serial Communications Interface (SCI) plus
a synchronous Serial Peripheral Interface (SPI). The A/D converter is enhanced to 10 bits. The
MC68HC11G5 also includes a real time interrupt circuit and a Computer Operating Properly (COP)
watchdog system, as on the original MC68HC11A8.
The MC68HC11G7, which is similar to the MC68HC11G5 but with 24 kilobytes of ROM instead of
16 kilobytes, is described in Appendix A.
The MC68HC711G5, again similar to the MC68HC11G5 but with 16 kilobytes of EPROM instead
of ROM, is described in Appendix B.
This section outlines the general characteristics and special features of the MC68HC11G5 highdensity complementary metal oxide semiconductor (HCMOS) microcontroller unit (MCU).
1.2
FEATURES OF THE MOTOROLA MC68HC11G5 MCU
•
Low-power/high-performance M68HC11 CPU core
•
16 kilobytes of ROM
•
256 bytes of bootstrap ROM
•
512 bytes of static RAM
•
RAM, registers and I/O mappable to any 4k boundary
MC68HC11G5
INTRODUCTION
MOTOROLA
1-1
•
4 output compare (OC), 3 input capture (IC) and 3 selectable OC/IC channels
•
4 PWM timers, each with its own counter and programmable period and duty cycle
•
Dual event counter featuring phase-shifter, pulse accumulator, periodic timer and 256 clock
divider
•
8-channel, 10-bit A/D converter with 1, 4 and 8-channel scanning modes
•
COP watchdog timer and clock monitor
•
Serial I/O system incorporating asynchronous NRZ and synchronous SPI
•
Single Chip, Expanded, Bootstrap and Test modes of operation
•
84-pin PLCC package (quad surface mount plastic)
SCI
E
XTAL
Mode
Select
Oscillator
Pulse
Accumulator
Timer
M68HC11
Por t H
DDR H
PG7
PG6
PG5
PG4
PG3
PG2
PG1
PG0
Por t G
DDR G
EV0
EV1
EV2
PW4
PW3
PW2
PW1
Event
Counter
PAI
OC2
OC3
OC4
OC5/IC4
IC1
IC2
IC3
OC1
MRDY
PH7/MRDY
PH6/EVO
PH5/EVI1
PH4/EVI2
PH3/PW4
PH2/PW3
PH1/PW2
PH0/PW1
OC7/IC6
OC6/IC5
TCK
Periodic
Interrupt
COP
Watchdog
CPU
PWM
Timer
A/D
Converter
ROM
RAM
16K bytes
512 bytes
Por t J
TXD
RXD
Interrupts
DDR J
SPI
PJ3
PJ2/OC7/IC6
PJ1/OC6/IC5
PJ0/TCK
DDR A
Por t A
PD1/TXD
PD0/RXD
SS
SCK
MOSI
MISO
PA7/PAI
PA6/OC2
PA5/OC3
PA4/OC4
PA3/OC5/IC4
PA2/IC1
PA1/IC2
PA0/IC3
DDR E
Por t E
Por t D
DDR D
PD5/SS
PD4/SCK
PD3/MOSI
PD2/MISO
EXTAL
External clock option on Timer 2
MODB/V kam
•
MODA/LIR
2 separate 16-bit timers, each with its own E-clock divider circuitry
IRQ
Maximum of seven 8-bit, one 6-bit and one 4-bit I/O ports
•
XIRQ
•
HALT
Expanded non-multiplexed data/address buses give access to a total address space of 64
kilobytes
RESET
•
PE7/AN8
PE6/AN7
PE5/AN6
PE4/AN5
PE3/AN4
PE2/AN3
PE1/AN2
PE0/AN1
Vr h
Vr l
Non-multiplexed Address/Data Bus
Por t B
Por t F
3 x V SS
DDR C
R/W
PF7/A7
PF6/A6
PF5/A5
PF4/A4
PF3/A3
PF2/A2
PF1/A1
PF0/A0
PB7/A15
PB6/A14
PB5/A13
PB4/A12
PB3/A11
PB2/A10
PB1/A9
PB0/A8
Por t C
PC7/D7
PC6/D6
PC5/D5
PC4/D4
PC3/D3
PC2/D2
PC1/D1
PC0/D0
3 x V DD
Figure 1-1. Functional Block Diagram
MOTOROLA
1-2
INTRODUCTION
MC68HC11G5
SECTION 2
OPERATING MODES AND SIGNAL DESCRIPTION
This section describes the operating modes and signals of the MC68HC11G5 MCU.
2.1
OPERATING MODES
During reset the MC68HC11G5 uses two mode select pins, MODA and MODB, to select one of two
normal modes or one of two special operating modes. The normal operating modes are the single
chip mode, which allows maximum use of the pins for on-chip peripheral functions, and the
expanded non-multiplexed mode which allows access to the 64 kbytes of memory space including
the internal RAM, ROM (if present), and register spaces. The special operating modes are the
bootstrap mode (which causes all vectors to be fetched from the on-chip bootstrap ROM), and the
test mode (which is an expanded mode allowing special testing functions on the MCU subsystems).
The special operating modes have access to certain privileged control bits which are not available
in the normal operating modes.
Mode selection, according to the values encoded on the mode select pins (MODA and MODB), is
shown in Table 2-1. The states of MODA and MODB, captured during reset determine the logic state
of the Special Mode (SMOD) and the Mode A Select (MDA) control bits in the HPRIO register.
Table 2-1. Mode Select Summary
Input Pins
Latched at Reset
MODA
MODB
0
1
Single Chip
0
0
1
1
Expanded Non-Multiplexed
0
1
0
0
Bootstrap
1
0
1
0
Test
1
1
MC68HC11G5
Mode Selected
SMOD
OPERATING MODES AND SIGNAL DESCRIPTION
MDA
MOTOROLA
2-1
2.1.1
Single Chip Operating Mode
In single chip mode, the MCU functions as a self-contained microcontroller and has no external
address or data bus. This mode provides maximum use of the pins for on-chip peripheral functions
(66 pins). In single chip mode the R/W line is always high (read) to facilitate changing mode.
2.1.2
Expanded Non-Multiplexed Operating Mode
In the expanded non-multiplexed mode, the MCU can address up to 64 kbytes of address space.
High order address bits are output on Port B and low order address bits are output on Port F. The
bidirectional data bus is on Port C and the R/W pin is used to control the direction of data transfer
on this bus.
2.1.3
Bootstrap Operating Mode
This is a very versatile operating mode since there are essentially no limitations on the special
purpose program that can be loaded into internal RAM. The resident bootstrap program, contained
in the bootstrap ROM, uses the SCI to read a variable length program into on-chip RAM. Program
control is passed to RAM at location $0000 when an idle line of at least four characters occurs.
The MC68HC11G5 communicates through the SCI port. After reset in bootstrap mode, the SCI runs
at E/16 (7812 baud for E-clock = 2 MHz). A break condition is output on the SCI transmitter. For
normal use of the bootstrap program, the user must send $FF to the SCI receiver at either E/16 or
E/104 (1200 baud for E-clock = 2 MHz).
Note: The $FF is not echoed through the SCI transmitter.
In this mode all interrupt vectors are mapped to pseudo-vectors in RAM (refer to Table 2-2). This
allows programmers to use their own service-routine addresses. Each pseudo-vector is allowed
three bytes of space, rather than the two bytes for normal vectors, because an explicit jump (JMP)
opcode is needed to cause the desired jump to the user’s service-routine address.
Since the SMOD control bit is initialized to one, all of the privileged control bits are accessible in this
mode. This allows the bootstrap mode to be used for test and diagnostic functions on completed
modules. Mode switching can occur under program control by writing to the SMOD and MDA bits
of the HPRIO register.
2.1.4
Test Operating Mode
This special expanded mode is primarily intended for factory testing. In this mode the reset and
interrupt vectors are fetched externally from locations $BFFE – $BFFF. The SMOD bit in the HPRIO
register will be set, indicating that a special mode is in effect and allowing the user to write to certain
privileged control bits which are normally read-only bits. Also, a special register, TEST1, is enabled
which allows several factory test functions to be invoked.
It is also possible to change from the test mode to a normal operating mode by writing a zero to the
SMOD bit. Once this bit is cleared, it cannot be changed back to one without going through a reset
sequence.
MOTOROLA
2-2
OPERATING MODES AND SIGNAL DESCRIPTION
MC68HC11G5
Table 2-2. Bootstrap Mode Jump Vectors
Address
MC68HC11G5
Pseudo-vector
00B5
Event 2
00B8
Event 1
00BB
Timer Overflow 2
00BE
Timer Output Compare 7 / Input Capture
00C1
Timer Output Compare 6 / Input Capture
00C4
SCI
00C7
SPI
00CA
Pulse Accumulator Input Edge
00CD
Pulse Accumulator Overflow
00D0
Timer Overflow 1
00D3
Timer Output Compare 5 / Input Capture
00D6
Timer Output Compare 4
00D9
Timer Output Compare 3
00DC
Timer Output Compare 2
00DF
Timer Output Compare 1
00E2
Timer Input Capture 3
00E5
Timer Input Capture 2
00E8
Timer Input Capture 1
00EB
Real Time Interrupt
00EE
IRQ
00F1
XIRQ
00F4
SWI
00F7
Illegal Op-code
00FA
COP Fai
00FD
Clock Monitor
BF40
Reset
OPERATING MODES AND SIGNAL DESCRIPTION
MOTOROLA
2-3
2.1.4.1 Factory Test Register (TEST1)
7
$103E
RESET:
6
5
4
3
TILOP TPWSL OCCR CBYP1 DISR
0
0
0
0
2
1
0
FCM
FCOP
CBYP2
0
0
0
0
READ:
Any time (always zero if not in a test mode)
WRITE:
Only while SMOD = 1 (TEST or BOOT modes)
TEST1
TILOP — Test Illegal Opcode
0 – Normal operation (trap on illegal opcodes)
1 – Stop giving LIR when an illegal opcode is found
This test mode allows testing of all illegal opcodes serially without servicing an
interrupt after each illegal opcode is received. LIR (inactive for illegal opcodes) is
used to monitor correct CPU operation.
TPWSL — Pulse Width Modulation Scaled Clock
0 – Normal operation
1 – Clock S (Scaled) from the PWM timer is output to and readable on the PWSCAL
register. Normal writing of the PWSCAL register will still function.
OCCR — Output Condition Code Register Status to Timer Port
0 – Normal operation
1 – The Condition Code bits H, N, Z, V, and C are driven out of the 5 most significant
bits (bits 3 – 7, respectively) of the timer I/O port to allow the test system to
monitor CPU operation.
CBYP1 — Timer Counter 1 Divider Chain By-pass
0 – Normal operation
1 – 16-bit free running timer counter 1 is divided into 8-bit halves and the prescaler is
by-passed. The system E-clock drives both halves directly.
DISR — Disable Resets from COP and Clock Monitor
0 – Normal operation
1 – Regardless of other control bit states, COP and clock monitor will not generate a
system reset.
When the device is reset in test or bootstrap mode (SMOD = 1), the DISR bit is initialized
to 1 so that resets from the COP and clock monitor are disabled. When reset in normal
modes, the DISR bit is initialized to 0.
FCM — Force Clock Monitor Failure
0 – Normal operation
1 – Immediately generates a Clock Monitor failure reset. Note that the CME bit must
also be set for the reset to be forced.
MOTOROLA
2-4
OPERATING MODES AND SIGNAL DESCRIPTION
MC68HC11G5
FCOP — Force COP Watchdog Failure
0 – Normal operation
1 – Immediately generates a COP failure reset. Note that COP must be otherwise
enabled for the reset to be generated; NOCOP = 0.
CBYP2 — Timer Counter 2 Chain By-pass
0 – Normal operation
1 – 16-bit free running timer counter 2 is divided into 8-bit halves and the prescaler is
by-passed. The system E-clock drives both halves directly.
The DISR control bit has priority over the FCM and FCOP control bits such that, if DISR
is set to one, no reset results even when FCM or FCOP is set to one.
2.2
SIGNAL DESCRIPTION
The following table shows the pin usage for the MC68HC11G5.
5 Volt Supply (VDD, VDDL, VDDR)
Ground (VSS, VSSL, VSSR)
3
3
RESET
Oscillator (XTAL, EXTAL)
E
R/W
1
2
1
1
IRQ
XIRQ
HALT
Mode Select (Vkam & LIR)
1
1
1
2
Analog Reference (Vrh, Vrl)
2
8-bit Ports (7)
56
6-bit Port (1)
6
4-bit Port (1)
4
——————————————————————
Total
84 pins
The following paragraphs describe the input/output signals used by the various functions of
the MCU.
2.2.1
Input Power (VDD) and Ground (VSS)
Power is supplied to the MCU via three positive supply pins (VDD) and three ground pins (VSS). Note
that, for ease of identification, the VDD pins on the left and right sides of the device package are called
VDDL and VDDR, respectively. Similarly, the VSS pins on the left and right sides of the device package
are called VSSL and VSSR.
MC68HC11G5
OPERATING MODES AND SIGNAL DESCRIPTION
MOTOROLA
2-5
2.2.2
Reset (RESET)
This active low bidirectional control signal pin is used as an input to initialize the MC68HC11G5 to
a known start-up state, and as an open-drain output to indicate an internal computer operating
properly (COP) watchdog circuit or clock monitor failure. This reset signal is significantly different
from the reset signal used on other Motorola MCUs. Refer to SECTION 5: RESETS, INTERRUPTS
AND LOW POWER MODES before designing circuitry to generate or monitor this signal.
MCU
4xE
CMOS Compatible
External Oscillator
EXTAL
XTAL
NC or
10k – 100
Load
Figure 2-1. Oscillator circuits: (a) External oscillator connections
First MCU
25 pF*
220
Second MCU
EXTAL
EXTAL
10M
4xE
Crystal
25 pF*
XTAL
NC or
10k – 100k
Load
XTAL
* This value contains all stray capacitance
Figure 2-1. Oscillator circuits: (b) One crystal driving two MCUs
First MCU
25 pF*
EXTAL
10M
4xE
Crystal
25 pF*
XTAL
* This value contains all stray capacitance
Figure 2-1. Oscillator circuits: (c) Common crystal connections
MOTOROLA
2-6
OPERATING MODES AND SIGNAL DESCRIPTION
MC68HC11G5
2.2.3
Crystal Driver (XTAL) and External Clock Input (EXTAL)
These two pins provide the interface for either a crystal or a CMOS compatible clock to control the
internal clock generator circuitry. The frequency applied to these pins must be four times higher than
the desired E-clock rate. When a crystal is used, a 25 pF capacitor should be connected from each
of the XTAL and EXTAL pins to ground to ensure reliable start-up operation. When an external
CMOS compatible clock is used as an input to the EXTAL pin, the XTAL pin should be left
disconnected. However, a 10 kΩ to 100 kΩ load resistor to ground may be used to reduce RFI noise
emission. (See Figure 2-1.)
2.2.4
E-clock Output (E)
The E-clock pin provides an output for the internally generated E-clock, which can be used as a
timing reference. The frequency of the E-clock output is one quarter of the input frequency at the
XTAL and EXTAL pins. When the E-clock output is low, an internal process is taking place; when
high, data is being accessed. The signal is halted when the MCU is in STOP mode.
2.2.5
Read/Write (R/W)
This pin is used to control the direction of transfers on the external data bus in expanded nonmultiplexed mode. A logic zero level indicates that data is being written to the external data bus; a
logic one level indicates that a read cycle is in progress. R/W stays high during single-chip
and bootstrap modes to maintain the ‘read’ state for systems which switch modes.
2.2.6
Interrupt Request (IRQ)
The IRQ pin provides the capability to apply asynchronous interrupts to the MC68HC11G5. It is
software selectable, (using the IRQE bit in the OPTION register) with a choice of either negative
edge sensitive or level sensitive triggering, and is always configured to level sensitive by reset. This
pin requires an external pull-up resistor connected to VDD.
2.2.7
Non-Maskable Interrupt (XIRQ)
The XIRQ pin provides the capability for applying asynchronous non-maskable interrupts, after
reset initialization, to the MC68HC11G5. During reset, the X-bit in the condition code register is set
and any interrupt is masked until the MCU software enables it. The XIRQ input is level sensitive, and
requires an external pull-up resistor to VDD.
2.2.8
Halt (HALT)
This pin is used as a clean way to force the processor bus into a tri-state condition by means of an
external signal. When HALT is pulled low the processor completes execution of the present
instruction and then tri-states the address and data bus. When the HALT pin is released, the
processor continues normal execution.
The HALT pin can also be used as a “clean way” to put the part into reset. Once pulled into halt,
RESET can be pulled low, ensuring that the processor will be reset on an instruction boundary rather
than in the middle of an instruction.
MC68HC11G5
OPERATING MODES AND SIGNAL DESCRIPTION
MOTOROLA
2-7
2.2.9
Mode A/Load Instruction Register (MODA/LIR) and Mode B/Standby Voltage
(MODB/Vkam)
During reset, MODA and MODB are used to select one of the four basic operating modes. Refer to
Table 2-1 for mode selection and to paragraph 2.1: OPERATING MODES for additional details.
After the operating mode has been selected, the open drain LIR pin goes to an active low level during
the first E-clock cycle of each instruction. The LIR pin can be used as an aid to program debugging.
The Vkam signal is used as the input for RAM standby power and will retain the RAM contents during
power down.
2.2.10
A/D Converter Reference Voltages (Vrl, Vrh)
These two pins provide the reference high and low voltages to the internal Analog-to-Digital
converter circuitry. Refer to SECTION 9: ANALOG-TO-DIGITAL CONVERTER.
2.2.11
Port Signals
The 66 input/output (I/O) lines are arranged into seven 8-bit ports (ports A, B, C, E, F, G and H), one
6-bit port (Port D) and one 4-bit port (Port J). Most of these ports serve more than one purpose,
depending on the operating mode or peripheral functions selected. Table 2-3 shows the different
functions of each port pin in the four operating modes. For more detailed information on I/O ports
refer to Section 4: INPUT/OUTPUT PORTS.
MOTOROLA
2-8
OPERATING MODES AND SIGNAL DESCRIPTION
MC68HC11G5
Table 2-3. Port Signal Functions: (a) Expanded Non-multiplexed and Test Modes
Port
Bit
A
B
C
D
E
F
G
H
J
0
1
2
3
4
5
6
7
PA0/IC3
PA1/IC2
PA2/IC1
PA3/IC4/OC5 (and/or OC1)
PA4/OC4 (and/or OC1)
PA5/OC3 (and/or OC1)
PA6/OC2 (and/or OC1)
PA7/PA1 (and/or OC1)
A8
A9
A10
A11
A12
A13
A14
A15
D0
D1
D2
D3
D4
D5
D6
D7
PD0/RXD
PD1/TXD
PD2/MISO
PD3/MOSI
PD4/SCK
PD5/ SS
PE0/AN1
PE1/AN2
PE2/AN3
PE3/AN4
PE4/AN5
PE5/AN6
PE6/AN7
PE7/AN8
A0
A1
A2
A3
A4
A5
A6
A7
PG0
PG1
PG2
PG3
PG4
PG5
PG6
PG7
PH0/PW1
PH1/PW2
PH2/PW3
PH3/PW4
PH4/EVI2
PH5/EVI1
PH6/EVO
PH7/MRDY
PJ0/TCK
PJ1/IC5/OC6
PJ2/IC6/OC7
PJ3
Table 2-3. Port Signal Functions: (b) Single Chip and Bootstrap Modes
Port
Bit
A
B
C
D
E
F
G
H
J
0
1
2
3
4
5
6
7
PA0/IC3
PA1/IC2
PA2/IC1
PA3/IC4/OC5 (and/or OC1)
PA4/OC4 (and/or OC1)
PA5/OC3 (and/or OC1)
PA6/OC2 (and/or OC1)
PA7/PA1 (and/or OC1)
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
PC0
PC1
PC2
PC3
PC4
PC5
PC6
PC7
PD0/RXD
PD1/TXD
PD2/MISO
PD3/MOSI
PD4/SCK
PD5/ SS
PE0/AN1
PE1/AN2
PE2/AN3
PE3/AN4
PE4/AN5
PE5/AN6
PE6/AN7
PE7/AN8
PF0
PF1
PF2
PF3
PF4
PF5
PF6
PF7
PG0
PG1
PG2
PG3
PG4
PG5
PG6
PG7
PH0/PW1
PH1/PW2
PH2/PW3
PH3/PW4
PH4/EVI2
PH5/EVI1
PH6/EVO
PH7
PJ0/TCK
PJ1/IC5/OC6
PJ2/IC6/OC7
PJ3
MC68HC11G5
OPERATING MODES AND SIGNAL DESCRIPTION
MOTOROLA
2-9
This page intentionally left blank
MOTOROLA
2-10
OPERATING MODES AND SIGNAL DESCRIPTION
MC68HC11G5
SECTION 3
MEMORY AND CONTROL/STATUS REGISTERS
This section describes the memory, memory subsystems mapping, and the mapping of the control
and status registers of the MC68HC11G5 MCU.
3.1
ROM
The internal 16 kilobytes of ROM occupy the highest 16k addresses in the memory map ($C000 –
$FFFF). On coming out of reset, this ROM is enabled in the single chip, test and bootstrap modes.
This ROM is disabled when the ROMON bit in the CONFIG register is clear. This register bit is only
writable in the special modes, bootstrap and test. For normal single chip mode, the ROM is on
(ROMON = 1). In expanded mode the ROM is off (ROMON = 0) thus allowing the user to execute
a program in the external memory space. (See also SECTION 3.4.5: CHANGING MODES.)
3.2
BOOTSTRAP ROM
The 256 bytes of bootstrap ROM are located at memory locations $BF00 – $BFFF. The reset and
interrupt vectors, while in this mode, are addressed at $BFC0 – $BFFF. The interrupt vectors point
to pseudo-vectors located in RAM (see Section 2.1.3 and Table 2-2).
3.3
RAM
Using the INIT control register, the 512 byte block of static RAM is mappable to the start of any 4
kilobyte boundary in memory. The reset default position of the RAM is located at $0000 to $01FF.
If the internal registers are mapped in the same 4 kilobyte block as RAM, the registers will have
higher priority.
The RAM is implemented with static cells and retains its contents during WAIT, HALT and STOP
modes. The contents of the RAM can also be retained during power-down, by supplying a low
current back-up power source to the Vkam pin (MODB).
MC68HC11G5
MEMORY AND CONTROL/STATUS REGISTERS
MOTOROLA
3-1
3.4
MEMORY MAP
Each of the normal and special operating modes of the MC68HC11G5 has a default initial memory
map. In addition, there is a control register (CONFIG) which can be used to remove (disable) the
ROM from the memory map. After reset the INIT register (which is reset to $01 independent of mode
and may only be written under specific circumstances) can alter the mapping of RAM and internal
I/O resources under software control.
While in bootstrap mode, the restart and interrupt vectors are fetched from an alternate memory area
($BFC0 – $BFFF) in an internal bootstrap ROM. In the test mode, vectors are also fetched from the
alternate area ($BFC0 – $BFFF), however, since the bootstrap ROM is not enabled, these vectors
reside in external memory.
Figure 3-1 shows the memory maps for all four modes of operation: single chip, expanded nonmultiplexed, bootstrap and test. On-board memory locations are shown by the shaded areas and
the contents of these areas are described on the right.
3.4.1
Single Chip Mode
This normal operating mode is established by having a logic one level on the MODB/Vkam pin and
a logic zero level on the MODA/LIR pin at the rising edge of RESET. The ROMON bit in the CONFIG
register is a one out of reset in this mode, so that the user ROM appears in the map. The initial
memory map which results is also controlled by the state of three bits (RBOOT, SMOD, and MDA)
in the HPRIO control register which are initialized automatically by hardware prior to the rising edge
on RESET.
Initial conditions affecting the memory map are:
ROMON = 1, RBOOT = 0, SMOD = 0, MDA = 0
MOTOROLA
3-2
MEMORY AND CONTROL/STATUS REGISTERS
MC68HC11G5
$0000
External
$0000
$01FF
512 byte RAM
(May be remapped to any 4k
boundary by the INIT register)
$1000
$107F
128-byte Register Block
(May be remapped to any 4k boundary
by the INIT register)
External
$1000
$2000
$3000
$4000
$5000
$6000
External
$7000
External
$8000
$9000
256 bytes
Bootstrap
ROM
$BF00
$BFFF
$A000
$B000
$C000
$D000
$C000
$BFC0
$BFFF
Special Modes
Interrupt Vectors
$FFC0
$FFFF
Normal Modes
interrupt Vectors
16k ROM
$E000
$F000
$FFFF
$FFFF
Single
Chip
Expanded
Non-Multiplexed
Normal Modes
Bootstrap
Test
Special Modes
Figure 3-1. Memory Map
3.4.2
Expanded Non-multiplexed Mode
This normal operating mode is established by having a logic one level on both the MODB/Vkam pin
and the MODA/LIR pin at the rising edge of RESET. The ROMON bit in the CONFIG register is a
zero in this mode so that the user ROM does not appear in the map. The initial memory map which
results is also controlled by the state of three bits (RBOOT, SMOD, and MDA) in the HPRIO control
register which are initialized automatically by hardware prior to the rising edge on RESET.
Initial conditions affecting the memory map are:
ROMON = 0, RBOOT = 0, SMOD = 0, MDA = 1
MC68HC11G5
MEMORY AND CONTROL/STATUS REGISTERS
MOTOROLA
3-3
3.4.3
Special Bootstrap Mode
This special mode is established by having a logic zero level on both the MODB/Vkam pin and the
MODA/LIR pin at the rising edge of RESET. The ROMON bit in the CONFIG register is a one out
of reset in this mode, so that the user ROM appears in the map. The initial memory map which results
is also controlled by the state of three bits (RBOOT, SMOD, and MDA) in the HPRIO control register
which are initialized automatically by hardware prior to the rising edge on RESET.
Initial conditions affecting the memory map are:
ROMON = 1, RBOOT = 1, SMOD = 1, MDA = 0
3.4.4
Special Test Mode
This special mode is established by having a logic zero level on the MODB/Vkam pin and a logic one
level on the MODA/LIR pin at the rising edge of RESET. The ROMON bit in the CONFIG register
is a one out of reset in this mode, so that the user ROM appears in the map. The initial memory map
which results is actually controlled by the state of three bits (RBOOT, SMOD, and MDA) in the
HPRIO control register which were initialized automatically by hardware prior to the rising edge on
RESET.
Initial conditions affecting the memory map are:
ROMON = 1, RBOOT = 0, SMOD = 1, MDA = 1
3.4.5
Changing Modes
Changing the operating mode and the bits described above is subject to some restrictions in normal
modes. First of all, ROMON, RBOOT and SMOD will stay in their reset state. These bits cannot be
changed in the normal operating modes. In order to allow a user to have an expanded mode system
with the ROM on, the user is allowed to change MDA once only. This means that the user can bring
the device out of reset in single chip mode, and then write MDA to a 1, thus putting the part into
expanded mode with the ROM on (ROMON = 1).
If the user does not intend to change modes after coming out of reset, he may wish to write MDA
one time to the same state. As MDA may be written to only once; this will prevent an accidental write
from changing the mode at some later time.
In the special operating modes, ROMON, RBOOT and MDA may be written at any time to either 0
or 1. SMOD cannot be written back to a 1 after being written to a 0, because the part will no longer
be in a special mode.
3.5
SYSTEM CONFIGURATION
The MC68HC11G5 allows the user to configure the MCU system to his specific requirements via
hard wired options, such as the mode select pins, and via internal software programmable control
MOTOROLA
3-4
MEMORY AND CONTROL/STATUS REGISTERS
MC68HC11G5
registers. Two special internal registers (INIT and CONFIG) require further explanation. The INIT
control register allows the RAM and internal register block to be repositioned in the memory map
during software initialization. The CONFIG control register controls the presence of ROM in the
memory map as well as the NOCOP watch-dog system enable.
3.5.1
RAM and I/O Mapping Register (INIT)
The INIT register is a special purpose 8-bit register that is used during initialization to change the
default locations of RAM and control registers within the MCU memory map. It can be written to only
once, within the first 64 E-clock cycles after a reset, and thereafter becomes a read-only register.
$103D
RESET:
7
RAM3
6
RAM2
5
RAM1
4
RAM0
3
REG3
2
REG2
1
REG1
0
REG0
0
0
0
0
0
0
0
1
INIT
READ:
Any time
WRITE:
If SMOD = 0, may be written once only, and only during the first 64 cycles: after this time
the register becomes read-only. If SMOD = 1 (test or bootstrap mode), writes are always
permitted.
RAM3, RAM2, RAM1, RAM0 — Internal RAM map position
These four bits specify the four most significant bits of the 16-bit RAM address.
REG3, REG2, REG1, REG0 — Register block map position.
These four bits specify the four most significant bits of the 16-bit internal register space
address. For more details refer to the memory map.
Since the INIT register is set to $01 by reset, the default starting address is $0000 for RAM and $1000
for the 128 byte control and status register block. The upper four bits of the INIT register specify the
starting address for the 512 byte RAM, while the lower four bits specify the starting address for the
control and status register block. In each case, the four bits define the four most significant bits of
the 16-bit address.
If relocation conflicts occur between the RAM and the ROM, the RAM takes priority over the ROM
which simply becomes inaccessible at those locations. Similarly, if the control and status registers
are located so that they conflict with the RAM and/or ROM, the registers take priority and the RAM
and/or ROM at those locations become inaccessible. Also, if an internal resource conflicts with an
external device, no harmful conflict occurs. (Data from the external device is not applied to the
internal data bus, thus it cannot interfere with the internal read.)
MC68HC11G5
MEMORY AND CONTROL/STATUS REGISTERS
MOTOROLA
3-5
Note:
3.5.2
There are unused register locations in the 128 byte control and status register block.
Reads of these unused registers return data from the undriven internal data bus, not from
another source that happens to be located at the same address.
Configuration Control Register (CONFIG)
The CONFIG control register is used for system configuration control functions including removal
of ROM from the memory map, and enabling of the COP watch-dog system.
7
6
5
4
3
$103F
RESET:
2
1
NOCOP ROMON
0
CONFIG
See text
NOCOP — COP System Disable
READ:
Any time
WRITE:
If SMOD = 0, may be written once only, and only during the first 64 cycles: after
this time the bit becomes read-only. If SMOD = 1 (test or bootstrap mode),
writes are always permitted.
RESET:
0 (COP on) for SMOD = 0; 1 (COP off) for SMOD = 1
0 – COP system enabled (forces reset on timeout)
1 – COP system does not force reset on timeout
ROMON — ROM Enable
READ:
Any time
WRITE:
May not be written if SMOD = 0. If SMOD = 1, bit is writable at any time.
RESET:
1 (ROM on) for single chip, bootstrap and test modes; 0 (ROM off) for normal
expanded mode
1 – ROM is present in the memory map (at $C000 – $FFFF)
0 – ROM is disabled from the memory map
3.6
CONTROL/STATUS REGISTERS
The control and status registers used to control the operation of the MCU are contained in a 128 byte
block which can be relocated to any 4 kilobyte boundary in memory. Throughout this document,
control and status register addresses are displayed with the high order digit shown as a bold “1” to
indicate that the register block may be relocated to some 4 kilobyte memory page other than its
default position of $1000. Figure 3-2 is provides a complete list of the control and status registers
and reserved locations in this block of memory.
MOTOROLA
3-6
MEMORY AND CONTROL/STATUS REGISTERS
MC68HC11G5
$1000
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
$1001
DDA7
DDA6
DDA5
DDA4
DDA3
DDA2
DDA1
$1002
PG7
PG6
PG5
PG4
PG3
PG2
$1003
DDG7
DDG6
DDG5
DDG4
DDG3
$1004
PB7
PB6
PB5
PB4
$1005
PF7
PF6
PF5
$1006
PC7
PC6
$1007
DDC7
$1008
PORTA
I/O Port A
DDA0
DDRA
Data Direction for Port A
PG1
PG0
PORTG
I/O Port G
DDG2
DDG1
DDG0
DDRG
Data Direction for Port G
PB3
PB2
PB1
PB0
PORTB
I/O Port B
PF4
PF3
PF2
PF1
PF0
PORTF
I/O Port F
PC5
PC4
PC3
PC2
PC1
PC0
PORTC
I/O Port C
DDC6
DDC5
DDC4
DDC3
DDC2
DDC1
DDC0
DDRC
Data Direction for Port C
0
0
PD5
PD4
PD3
PD2
PD1
PD0
PORTD
I/O Port D
$1009
0
0
DDD5
DDD4
DDD3
DDD2
DDD1
DDD0
DDRD
Data Direction for Port D
$100A
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
PORTE
I/O Port E
$100B
FOC1
FOC2
FOC3
FOC4
FOC5
FOC6
FOC7
0
CFORC
Compare Force Register
$100C OC1M7 OC1M6 OC1M5 OC1M4 OC1M3
0
0
0
OCIM
OC1 Action Mask Register
$100D OC1D7 OC1D6 OC1D5 OC1D4 OC1D3
0
0
0
OCID
OC1 Action Data Register
$100E
$100F
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TCNT1
Timer Counter Register 1
$1010
$1011
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TIC1
Input Capture 1 Register
$1012
$1013
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TIC2
Input Capture 2 Register
$1014
$1015
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TIC3
Input Capture 3 Register
$1016
$1017
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TOC1
Output Compare 1 Register
$1018
$1019
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TOC2
Output Compare 2 Register
$101A
$101B
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TOC3
Output Compare 3 Register
$101C
$101D
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TOC4
Output Compare 4 Register
$101E
$101F
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TO5I4
Output Compare 5/
Input Capture 4 Register
Figure 3-2. Control and Status Registers (Page 1)
MC68HC11G5
MEMORY AND CONTROL/STATUS REGISTERS
MOTOROLA
3-7
$1020
OM2
OL2
OM3
TCTL1
Timer Control Register 1
$1021 EDG4B EDG4A EDG1B EDG1A EDG2B EDG2A EDG3B EDG3A
TCTL2
Timer Control Register 2
$1022
OC1I
OC2I
OC3I
OC4I
4/5I
IC1I
IC2I
IC3I
TMSK1
Main Timer Interrupt Mask Register 1
$1023
OC1F
OC2F
OC3F
OC4F
4/5F
IC1F
IC2F
IC3F
TFLG1
Main Timer Interrupt Flag Register 1
$1024
TO1I
RTII
PAOVI
PAII
TO2I
5/6I
6/7I
0
TMSK2
Misc. Timer Interrupt Mask Register 2
$1025
TO1F
RTIF
PAOVF
PAIF
TO2F
5/6F
6/7F
0
TFLG2
Misc. Timer Interrupt Flag Register 2
$1026
0
PAEN
I4/O5
RTR2
RTR1
RTR0
PACTL
Pulse Accumulator Control Register
$1027
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PACNT
Pulse Accumulator Count Register
$1028
SPIE
SPE
DWOM
MSTR
CPOL
CPHA
SPR1
SPR0
SPCR
SPI Control Register
$1029
SPIF
WCOL
0
MODF
0
0
0
0
SPSR
SPI Status Register
$102A
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SPDAT
SPI Data Register
$102B
TCLR
0
SCP1
SCP0
RCKB
SCR2
SCR1
SCR0
BAUD
SCI Baud Rate Control
$102C
R8
T8
0
M
WAKE
0
0
0
SCCR1
SCI Control Register 1
$102D
TIE
TCIE
RIE
ILIE
TE
RE
RWU
SBK
SCCR2
SCI Control Register 2
$102E
TDRE
TC
RDRF
IDLE
OR
NF
FE
0
SCSR
SCI Status Register
$102F
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
SCDAT
SCI Data (Read RDR, Write TDR)
$1030
CCF
MULT
CD
CC
CB
CA
ADCTL
A/D Control Register
$1031
0
0
0
0
PJ3
PJ2
PJ1
PJ0
PORTJ
I/O Port J
$1032
0
0
0
0
DDJ3
DDJ2
DDJ1
DDJ0
DDRJ
Data Direction for Port J
$1033
PH7
PH6
PH5
PH4
PH3
PH2
PH1
PH0
PORTH
I/O Port H
$1034
DDH7
DDH6
DDH5
DDH4
DDH3
DDH2
DDH1
DDH0
DDRH
Data Direction for Port H
$1035
0
0
0
0
0
0
0
0
Reserved
$1036
0
0
0
0
0
0
0
0
Reserved
$1037
0
0
0
0
0
0
0
0
Reserved
0
IRV
0
0
PAMOD PEDGE
CONV8 SCAN
$1038 GWOM CWOM
$1039
ADPU
CSEL
$103A
Bit 7
$103B
0
OL3
OM4
OL4
OM5
OL5
MRDY NHALT
OPT2
System Configuration Options 2 Reg.
System Configuration Options
IRQE
DLY
CME
0
CR1
CR0
OPTION
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
COPRST Arm/Reset COP Timer Circuitry
0
0
0
0
0
0
0
MDA
PSEL4
PSEL3
PSEL2
PSEL1
PSEL0
HPRIO
RAM1
$103C RBOOT SMOD
Highest Priority I-Bit Interrupt and Misc.
$103D
RAM3
RAM0
REG3
REG2
REG1
REG0
INIT
$103E
TILOP TPWSL OCCR CBYP1
DISR
FCM
FCOP
CBYP2
TEST1
Factory Test Control Register
CONFIG
COP and ROM Enables
$103F
0
RAM2
Reserved
0
0
0
0
NOCOP ROMON
0
RAM and I/O Mapping Register
Figure 3-2. Control and Status Registers (Page 2)
MOTOROLA
3-8
MEMORY AND CONTROL/STATUS REGISTERS
MC68HC11G5
$1040
$1041
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR1
A/D Result Register 1
$1042
$1043
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR2
A/D Result Register 2
$1044
$1045
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR3
A/D Result Register 3
$1046
$1047
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR4
A/D Result Register 4
$1048
$1049
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR5
A/D Result Register 5
$104A
$104B
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR6
A/D Result Register 6
$104C
$104D
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR7
A/D Result Register 7
$104E
$104F
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
0
Bit 12
0
Bit 11
0
Bit 10
0
Bit 9
0
Bit 8
0
ADR8
A/D Result Register 8
$1050
EDG5B EDG5A EDG6B EDG6A
OM6
OL6
OM7
OL7
TCTL3
Timer Control Register 3
$1051
CT2SP CT1SP
I5/O6
I6/O7 TCTL4
Timer Control Register 4
$1052
$1053
Bit 15
Bit 7
$1054
$1055
$1056
$1057
0
0
0
0
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TCNT2
Timer Counter Register 2
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TO6I5
Output Compare 6/
Input Capture 5 Register
Bit 15
Bit 7
Bit 14
Bit 6
Bit 13
Bit 5
Bit 12
Bit 4
Bit 11
Bit 3
Bit 10
Bit 2
Bit 9
Bit 1
Bit 8
Bit 0
TO7I6
Output Compare 7/
Input Capture 6 Register
PR2B
PR2A
0
0
PR1B
PR1A
TPRE
Timer Prescaler Register
$1058 TEDGB TEDGA
$1059
0
0
0
0
0
0
0
0
Reserved
$105A
0
0
0
0
0
0
0
0
Reserved
$105B
0
0
0
0
0
0
0
0
Reserved
$105C
0
0
0
0
0
0
0
0
Reserved
$105D
0
0
0
0
0
0
0
0
Reserved
$105E
0
0
0
0
0
0
0
0
Reserved
$105F
0
0
0
0
0
0
0
0
Reserved
Figure 3-2. Control and Status Registers (Page 3)
MC68HC11G5
MEMORY AND CONTROL/STATUS REGISTERS
MOTOROLA
3-9
PCKB3 PCKB2
PCKB1 PWCLK
PWM Timer Clock Select
$1061 PCLK4 PCLK3 PCLK2 PCLK1 PPOL4 PPOL3 PPOL2
PPOL1 PWPOL
PWM Timer Polarity
$1062
Bit 7
Bit 6
Bit 5
Bit 4
Bit 0
$1063
0
0
0
0
$1064
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWCNT1 PWM Timer Counter 1
$1065
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWCNT2 PWM Timer Counter 2
$1066
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWCNT3 PWM Timer Counter 3
$1067
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWCNT4 PWM Timer Counter 4
$1068
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWPER1 PWM Timer Period 1
$1069
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWPER2 PWM Timer Period 2
$106A
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWPER3 PWM Timer Period 3
$106B
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWPER4 PWM Timer Period 4
$106C
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWDTY1 PWM Timer Duty 1
$106D
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWDTY2 PWM Timer Duty 2
$106E
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWDTY3 PWM Timer Duty 3
$106F
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PWDTY4 PWM Timer Duty 4
$1070
0
0
$1060 CON34 CON12 PCKA2 PCKA1
$1071 EVOEN EVPOL
EVMDB EVMDA
0
Bit 3
Bit 2
Bit 1
PWSCAL PWM Timer Prescaler
PWEN4 PWEN3 PWEN2 PWEN1 PWEN
0
PWM Timer Enable
EVCKC EVCKB
EVCKA EVCLK
Event Counter Clock Select
EVI2C
EVI2B
EVI2A
EVI1C
EVI1B
EVI1A
EVCTL
Event Counter Control Register
$1072 EVCEN
0
0
0
0
0
EV2I
EV1I
EVMSK
Event Counter Interrupt Mask Register
$1073
0
0
0
0
0
0
EV2F
EV1F
EVFLG
Event Counter Interrupt Flag Register
$1074
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
EVCNT1
Event Counter Count Register 1
$1075
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
EVCNT2
Event Counter Count Register 2
$1076
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ECMP1A
Event Counter Compare Register 1A
$1077
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ECMP2A
Event Counter Compare Register 2A
$1078
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ECMP1B
Event Counter Compare Register 1B
$1079
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ECMP2B
Event Counter Compare Register 2B
$107A
0
0
0
0
0
0
0
0
Reserved
$107B
0
0
0
0
0
0
0
0
Reserved
$107C
0
0
0
0
0
0
0
0
Reserved
$107D
0
0
0
0
0
0
0
0
Reserved
$107E
0
0
0
0
0
0
0
0
Reserved
$107F
0
0
0
0
0
0
0
0
Reserved
Figure 3-2. Control and Status Registers (Page 4)
MOTOROLA
3-10
MEMORY AND CONTROL/STATUS REGISTERS
MC68HC11G5
SECTION 4
INPUT/OUTPUT PORTS
There are seven 8-bit I/O ports, one 6-bit I/O port and one 4-bit I/O port on the MC68HC11G5. Most
of the 66 I/O pins serve multiple purposes depending on the configuration of the MCU system
(see Table 2-3). The configuration is controlled in turn, by hardware mode selection as well as by
several internal control registers.
Ports A, C, D, G, H, and J may be used as general purpose input and/or output pins as specified
by DDRA, DDRC, DDRD, DDRG, DDRH, and DDRJ. Ports B, E, and F have fixed data direction and
thus do not require DDR control registers.
Port signals can always be sensed (read) even if they are configured as general purpose outputs
or are dedicated to on-chip peripheral functions. Reading the port address returns the sensed logic
level at the pin when the pin is configured as an input, and the logic sense at the input to the pin driver
is sensed when the pin is configured as an output.
I/O pins default to being general purpose I/O lines unless an internal function which uses that pin
is specifically enabled. When a pin is dedicated to an internal peripheral function the associated
DDR bit in some cases still controls whether the line is an input or an output. The SPI, timer input
captures and pulse accumulator follow this rule.
Several functions override the state of the DDRs. The SCI forces the I/O state of the two associated
Port D lines. The timer also forces the I/O state of each associated Port A line when an output
compare using a Port A or Port J line is enabled. Both the PWM timer and the event counter
also override the associated DDR bits. In these cases the data direction bits will have no effect on
these lines.
When a pin is dedicated to an on-chip peripheral function, writes to the associated PORTx bit do
not affect the pin but are stored in an internal latch such that, if the pin becomes available for general
purpose output, the driven level will be the last value written to the PORTx bit.
4.1
MODE DEPENDENCIES
The MCU mode is controlled by two mode select bits (SMOD and MDA) in the HPRIO register which
are in turn controlled by the two mode select pins (MODA and MODB).
In the expanded modes (normal expanded and test), ports B, C, E and F, R/W, and LIR are dedicated
to address, data, and control signals and may not be used for alternate I/O functions. In order to
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-1
preserve the Port functions that are displaced by the expanded modes, these functions become
externally accessible functions so that they may be emulated with external hardware, if required.
The internal register addresses that become external accesses are PORTB, DDRC, PORTC
and PORTF.
4.2
GENERAL PURPOSE I/O (PORTS A, C, D, G, H, AND J)
As general purpose I/O lines, each pin has associated with it a bit in a PORTx data register and a
bit in the corresponding position in a DDRx register. The data direction register (DDRx) is used to
specify the primary direction of data on the I/O pin. However, specification of a line as an output does
not prevent reading of the line as an input. When a bit configured as an output is read, there are two
kinds of data which may be returned, depending on the internal circuitry of the port. Reading Port
A, Port H, or Port J returns the values sensed at the pins. Reading Port C, Port D, or Port G returns
the values at the inputs to the pin drivers.
When a line is configured as an input by clearing the DDRx bit, the pin becomes a high impedance
input. If a write is executed to a line that is configured as an input, the value will not affect the I/O
pin but the bit will be stored in an internal latch so that, if the line is later reconfigured as an output,
this value will appear at the I/O pin. This operation can be used to preset a value for an output port
prior to configuring it as an output, thereby avoiding glitches on the outputs which may be detrimental
to the operation of the external system.
Ports C, D, and G each have a wired-OR mode of operation which is controlled by the CWOM,
DWOM, and GWOM bits, respectively. If the corresponding xWOM bit is set, the p-channel drivers
in the output buffers are disabled.
Note:
4.3
bits 6 and 7 of Port D and bits 4 through 7 of Port J are not implemented.
FIXED DIRECTION I/O (PORTS B, E, AND F)
The pins for ports B, E, and F have fixed data directions and consequently do not have data direction
registers associated with them. When ports B and F are being used for general purpose I/O, they
are configured as output only ports and reading them returns the levels sensed at the inputs of the
pin drivers. Port E supports the eight A/D channel inputs but these pins may also be used as general
purpose digital inputs. Writing to the Port E address has no meaning or effect.
4.4
PORT A
Port A is an 8-bit bidirectional port. Port A pins can be used as general purpose I/O or for timer
functions. Each pin behaves as a general purpose I/O bit by default, unless a timer function using
that bit is specifically enabled. As general purpose I/O, the data direction of Port A pins are
determined by the corresponding DDRA bits. The directions of Port A bits 0, 1, and 2 are always
MOTOROLA
4-2
INPUT/OUTPUT PORTS
MC68HC11G5
controlled by the DDRA bits whether IC3, IC2, and IC1 are enabled or not. Port A bits 3 – 7 are
controlled by the DDRA bits only when the associated output compare functions are disabled.
Enabling an output compare function forces the corresponding port bit to be an output, irrespective
of the state of the DDRA bit. Using any pins of Port A for timer functions has no effect on the ability
to read these pins as inputs (because input sensing logic is always connected to the port pins).
The OC2, OC3, OC4, and OC5 lines out of Port A are enabled by pairs of control bits in the TCTL1
register. The output compare 1 function is unique in that it allows automatic timer control of any
combination of the five most significant bits of Port A regardless of whether or not they are being
used for another timer function. The OC1 function gains control of Port A bits by setting the
corresponding bits in the OC1M control register. The IC1, IC2, IC3, and IC4 input of Port A are
enabled by pairs of control bits in the TCTL2 register. (See SECTION 6: PROGRAMMABLE
TIMER, REAL TIME INTERRUPT AND PULSE ACCUMULATOR.)
The IC4 function and OC5 function share the same Port A bit and they are selected by the I4/O5
bit in the PACTL register. The pulse accumulator system is enabled, on Port A bit 7 as an input, by
setting the PAEN bit in the PACTL register. Even while the pulse accumulator is enabled, Port A bit
7 may be configured as an output controlled by OC1 or as a general purpose output.
4.4.1
Data Register (PORTA )
$1000
7
PA7
6
PA6
5
PA5
4
PA4
3
PA3
2
PA2
1
PA1
0
PA0
RESET:
Alternate Pin Function:
and/or:
0
PA1
OC1
0
OC2
OC1
0
OC3
OC1
0
OC4
OC1
0
OC5/IC4
OC1
0
IC1
—
0
IC2
—
0
IC3
—
PORTA
READ:
Any time (inputs return pin levels; outputs return pin driver input levels).
WRITE:
Data stored in an internal latch. (Drives pins only if configured as outputs.)
RESET:
General purpose high impedance inputs ($00).
Note:
Writes do NOT change pin state when pin is configured for timer output.
4.4.2
Data Direction Register (DDRA )
$1001
7
DDA7
6
DDA6
5
DDA5
4
DDA4
3
DDA3
2
DDA2
1
DDA1
0
DDA0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00 (all general purpose I/O configured for input only).
DDRA
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-3
Note:
4.5
The timer forces each Port A line associated with an enabled output compare to be an
output. In such cases the data direction bits will not be changed but will have no effect
on these lines. DDRA will revert to controlling the I/O state of a pin when the associated
timer output compare is disabled.
PORT B
Port B is an 8-bit general purpose output port which also supports the external address bus.
In the expanded modes (normal expanded and test), these pins act as the high order address output
pins. During each MCU cycle, bits 8 through 15 of the address are driven out of bits 0 through 7 of
Port B. When the NHALT bit in the OPT2 register is cleared and the HALT input is pulled low, all
output buffers of Port B bits go tri-state.
In the single chip modes (normal and bootstrap), the Port B pins are general purpose output only
pins. Reading Port B in these modes returns the sensed levels at the inputs to the Port B pin drivers.
The Port B data register is cleared at reset and all Port B bits output logic zeros.
4.5.1
Data Register (PORTB)
$1004
RESET:
Alternate Pin Function:
7
6
5
4
3
2
1
0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
0
0
0
0
0
0
0
0
A15
A14
A13
A12
A11
A10
A9
A8
PORTB
READ:
Any time (returns levels sensed at inputs of Port B pin drivers).
WRITE:
Data stored in internal latch (drives pins only if configured as general purpose outputs).
RESET:
In single chip modes, all Port B pins are general purpose output only pins (all zeros).
In expanded modes, all Port B pins are high order address signal outputs.
4.6
PORT C
Port C is an 8-bit bidirectional port. Port C pins serve one of two basic functions depending on the
MCU mode selected; bidirectional data lines or general purpose I/O pins. In either mode, if the
CWOM bit in the OPT2 register is set, the p-channel drivers in the output buffers are disabled (wiredOR mode).
In the expanded modes (normal expanded and test), these pins act as bidirectional data pins.
During the CPU read cycle, data on the Port C pins are latched internally on the falling edge of E.
During the CPU write cycle, the internal data is driven out of Port C and is valid at the falling edge
of E. During an internal address read cycle with the IRV bit in the OPT2 register set, the internal data
is also driven out of Port C and is valid at the falling edge of E. If the MCU is in the Halt state, all Port
C bits become tri-state.
MOTOROLA
4-4
INPUT/OUTPUT PORTS
MC68HC11G5
In the single chip modes (normal and bootstrap), the Port C pins are general purpose I/O pins. Bits
0 – 7 are input or output pins depending on the corresponding bit of DDRC. While a bit is configured
as an output, reading the bit returns the sensed level at the input to the Port C pin driver. At reset,
all DDRC bits are cleared and all Port C bits are configured as inputs.
4.6.1
Data Register (PORTC)
$1006
7
6
5
4
3
2
1
0
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
RESET:
0
0
0
0
0
0
0
0
Alternate Pin Function:
D7
D6
D5
D4
D3
D2
D1
D0
PORTC
READ:
Any time (inputs return pin level; outputs return pin driver input level).
WRITE:
Data stored in internal latch (drives pins only if configured as outputs)
RESET:
In single chip modes all Port C pins are configured as general purpose inputs.
In expanded modes, Port C is configured as the data bus.
4.6.2
Data Direction Register (DDRC)
$1007
7
DDC7
6
DDC6
5
DDC5
4
DDC4
3
DDC3
2
DDC2
1
DDC1
0
DDC0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00 (all general purpose I/O configured for input only).
DDRC
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
4.7
PORT D
Port D is a 6-bit bidirectional port which also supports the SCI and SPI systems. When the SCI or
SPI is not needed the associated pins may be used for general purpose I/O.
Port D pins serve several functions depending on the MCU mode and various internal control
registers. If the DWOM bit in the SPCR register is set, the p-channel drivers in the output buffers are
disabled (wired-OR mode).
Port D bit 0 becomes the Receive Data input (RXD) when the SCI receiver is enabled (RE bit in the
SCCR2 register set to one). When the RE bit is clear, Port D bit 0 defaults to being a general purpose
I/O pin controlled by DDRD.
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-5
Port D bit 1 becomes the Transmit Data output (TXD) when the SCI transmitter is enabled (TE bit
in the SCCR2 register set to one). When the TE bit is clear, Port D bit 1 defaults to being a general
purpose I/O pin controlled by DDRD. Note that the transmit logic will retain control of Port D bit 1 after
TE is cleared until all transmit operations have finished, including completion of transmission of data
from the serial shifter, a queued idle, or queued break.
In a test mode, the RCKB test bit in the BAUD register may be set. When RCKB is set, the 16X
receiver baud rate clock and the 1X transmitter clock are exclusive-ORed and driven out of the Port
D bit 1 pin. The RCKB bit can be written only in the test or bootstrap modes and it overrides any other
use of the Port D bit 1 pin.
Bits 2 – 5 of Port D are dedicated to the serial peripheral interface function (SPI) whenever the SPE
bit in the SPCR register is set (SPI enabled). Note that Port D bit 5 still responds to DDRD bit 5 such
that, if the DDR bit is set, the Port D bit 5 pin is given up by the SPI system to become a general
purpose output pin if and only if the SPI is in master mode. When the SPE bit is clear, bits 2 – 5 of
Port D default to being general purpose I/O pins controlled by DDRD.
The four SPI interface lines are described in greater detail in SECTION 8: SERIAL PERIPHERAL
INTERFACE.
4.7.1
Data Register (PORTD)
$1008
7
6
5
4
3
2
1
0
0
0
PD5
PD4
PD3
PD2
PD1
PD0
RESET:
0
0
0
0
0
0
0
0
Alternate Pin Function:
—
—
SS
SCK
MOSI
MISO
TXD
RXD
PORTD
READ:
Any time (inputs return pin level; outputs return pin driver input level). Bits 6 and 7 always
read as zeros.
WRITE:
Data stored in internal latch (drives pins only if configured as outputs). Writes to bit 6 and
7 have no meaning or effect.
RESET:
Bits 0 – 5 are configured as general purpose inputs.
4.7.2
Data Direction Register (DDRD)
$1009
7
0
6
0
5
DDD5
4
DDD4
3
DDD3
2
DDD2
1
DDD1
0
DDD0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time (reads of bits 6 and 7 always return zeros).
WRITE:
Any time (writes to bits 6 and 7 have no meaning or effect).
MOTOROLA
4-6
INPUT/OUTPUT PORTS
DDRD
MC68HC11G5
RESET:
$00 (all general purpose I/O configured for input only).
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
Bit 5 of Port D is dedicated as the active low slave select (SS) input, when the SPI system is enabled.
In SPI slave mode, DDRD bit 5 has no meaning or effect. In SPI master mode, DDRD bit 5
determines whether Port D bit 5 is an error detect input to the SPI (DDRD bit clear) or a general
purpose output line (DDRD bit set).
For bits 2, 3, & 4 (MISO, MOSI, & SCK): if the SPI is enabled and expects the bit to be an input, it
will be an input regardless of the state of the DDRD bit; if the SPI is enabled and expects the bit to
be an output, it will be an output only if the DDRD bit is set.
4.8
PORT E
Port E is an 8-bit port which supports the 8-channel A/D converter. Any channels not used
for A/D may be used as general purpose inputs.
Since there is no output drive logic associated with Port E there is no DDRE register. Port E pins
are capable of withstanding negative 1 volt transients (current limited by an external 10 kΩ or greater
resistor) without affecting MCU operation, other than possible loss of the A/D input sample for a
conversion being performed at the time of the transient. Using Port E pins as A/D inputs does not
affect the ability to read these pins as static inputs. However, reading Port E during an A/D
conversion sequence may inject noise into the analog input signals and may result in reduced
accuracy of the A/D result. Note that performing a digital read of Port E, with levels other than VDD
or VSS on the Port E pins, will result in greater power dissipation during the read cycle.
4.8.1
Data Register (PORTE)
$100A
RESET:
Alternate Pin Function:
7
6
5
4
3
2
1
0
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
U
U
U
U
U
U
U
U
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
READ:
Any time (returns sensed levels at Port E pins).
WRITE:
Has no meaning or effect.
RESET:
Does not affect this address.
MC68HC11G5
INPUT/OUTPUT PORTS
PORTE
MOTOROLA
4-7
4.9
PORT F
Port F is an 8-bit general purpose output port which also supports the external address bus.
In the expanded modes (normal expanded and test), these pins act as the low order address output
pins. During each MCU cycle, bits 0 – 7 of the address are driven out of bits 0 – 7 of Port F. When
the NHALT bit in the OPT2 register is cleared and the HALT input is pulled low, all output buffers
on Port F pins go tri-state.
In the single chip modes (normal and bootstrap), the Port F pins are general purpose output only
pins. Reading Port F in these modes returns the sensed levels at the inputs to the Port F pin drivers.
The Port F data register is cleared at reset and all Port F bits output logic zeros.
4.9.1
Data Register (PORTF)
$1005
7
PF7
6
PF6
5
PF5
4
PF4
3
PF3
2
PF2
1
PF1
0
PF0
RESET:
0
0
0
0
0
0
0
0
PORTF
READ:
Any time (returns sensed levels at inputs of Port F pin drivers).
WRITE:
Data stored in internal latch (drives pins only if configured as general purpose outputs).
RESET:
In single chip modes, all Port F pins are general purpose output only pins (all zeros).
In expanded modes, all Port F pins are low order address signal outputs.
4.10
PORT G
Port G is an 8-bit bidirectional port. Port G pins serve one of two basic functions depending on the
MCU mode selected; bidirectional data lines or general purpose I/O pins. In either mode, if the
GWOM bit in the OPT2 register is set, the p-channel drivers in the output buffers are disabled (wiredOR mode).
Port G may be programmed as an input or an output under software control. The data direction of
each pin is determined by the state of the corresponding bit in the Port G data direction register
(DDRG). A pin is configured as an output if its corresponding DDRG bit is set to a logic one; a pin
is configured as an input if its corresponding DDRG bit is cleared. At reset, all DDRG bits are cleared,
which configure all Port G pins as inputs.
During the programmed output state, a read of Port G actually reads the value of output data latch
and not the pin level. When the GWOM bit in OPT2 is set, the p-channel drivers of output buffers
are disabled (wired-OR mode).
MOTOROLA
4-8
INPUT/OUTPUT PORTS
MC68HC11G5
4.10.1
Data Register (PORTG)
$1002
7
PG7
6
PG6
5
PG5
4
PG4
3
PG3
2
PG2
1
PG1
0
PG0
RESET:
0
0
0
0
0
0
0
0
PORTG
READ:
Any time (inputs return pin levels; outputs return pin driver input levels).
WRITE:
Data stored in an internal latch (drives pins only if configured as outputs).
RESET:
General purpose high impedance inputs ($00)
4.10.2
Data Direction Register (DDRG)
$1003
7
DDG7
6
DDG6
5
DDG5
4
DDG4
3
DDG3
2
DDG2
1
DDG1
0
DDG0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00 (all general purpose I/O configured for input only).
DDRG
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
4.11
PORT H
Port H is an 8-bit general purpose I/O port. Three of the pins are used for the event counter (see
SECTION 11: EVENT COUNTER). Four of the remaining pins are used for the 4-channel PWM
timer (see SECTION 10: PULSE WIDTH MODULATION TIMER). The remaining pin is used for the
memory ready input signal (MRDY). Any pins not used for these functions may be used as general
purpose I/O.
When the PWENx bit in the PWEN register is set, the associated Port H bit is forced to be a PWM
output regardless of the state of the DDRH bit. This does not change the state of the DDRH bit. When
the PWENx bit in the PWEN register is cleared, the pin defaults to being a general purpose I/O. The
data direction of the pin is determined by the state of the corresponding DDRH bit.
Bits 4 and 5 of Port H are used as the EVI2 and EVI1 inputs or as general purpose I/O. The data
direction of Port H bits 4 and 5 is always under the control of DDRH bits 4 and 5, whether EVI2 and
EVI1 are enabled or not. If the pin is configured as an output by its DDRH bit, the output data of the
Port H register is also the input data of the event counter.
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-9
Bit 6 of Port H is used as the event output (EVO) or as general purpose I/O. When the EVOEN bit
in the EVCTL register is set, bit 6 of Port H becomes EVO regardless of the state of DDRH bit 6. This
does not change the state of DDRH bit 6. When the EVOEN bit in the EVCTL register is cleared,
the data direction of the pin is under the control of DDRH bit 6.
In the expanded non-multiplexed and test modes, bit 7 of Port H is used as the memory ready signal
(MRDY) or as general purpose I/O. When the MRDY bit in the OPT2 register is set, bit 7 of Port H
becomes the memory ready input regardless of the state of DDRH bit 7. When the MRDY bit in the
OPT2 register is cleared, the data direction of the pin is under the control of DDRH bit 7. In the single
chip and bootstrap modes, bit 7 of Port H is a general purpose I/O pin and the data direction of the
pin is determined by the state of DDRH bit 7.
Reading Port H reads the levels sensed at the pins regardless of the DDRH, PWENx, and EVOEN
bits. All DDRH bits are cleared at reset.
4.11.1
Data Register (PORTH)
7
$1033
PH7
RESET:
Alternate Pin Function:
6
5
4
3
2
1
0
PH6
PH5
PH4
PH3
PH2
PH1
PH0
0
0
0
0
0
0
0
0
MRDY
EVO
EVI1
EVI2
PW4
PW3
PW2
PW1
PORTH
READ:
Any time (inputs return pin levels, outputs return pin driver input levels).
WRITE:
Data stored in an internal latch (drives pins only if configured for output).
RESET:
General purpose high impedance inputs ($00).
4.11.2
Data Direction Register (DDRH)
$1034
7
DDH7
6
DDH6
5
DDH5
4
DDH4
3
DDH3
2
DDH2
1
DDH1
0
DDH0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time
WRITE:
Any time
RESET:
$00 (all general purpose I/O configured for input only)
DDRH
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
Note:
The pulse width modulation timer forces the I/O state to be an output for each Port H line
associated with an enabled PWM. In such cases, the data direction bits will not be
changed but have no effect on these lines. DDRH will revert to controlling the I/O state
of a pin when the associated function is disabled. The event counter does not force the
state of any of the associated pins.
MOTOROLA
4-10
INPUT/OUTPUT PORTS
MC68HC11G5
4.12
PORT J
Port J is a general purpose 4-bit I/O port which also supports some of the timer functions (see
SECTION 6: PROGRAMMABLE TIMER, REAL TIME INTERRUPT AND PULSE
ACCUMULATOR). Two of the pins are used for input capture/output compare. One of the pins is
used as a clock input for the timer counter registers. The one remaining pin is for general purpose
I/O. Any channels not used for timers may be used as general purpose I/O.
Bit 0 of Port J is used as the TCK input or for general purpose I/O. The data direction is always under
the control of DDRJ bit 0, whether TCK is enabled or not. If the pin is configured as an output by DDRJ
bit 0, the output data in Port J bit 0 becomes the input data to TCK.
Bits 1 and 2 of Port J is used for output compare or input capture or as general purpose I/O. If the
associated output compare is not enabled, the data directions of these pins are dependent on DDRJ
bits 1 and 2. If an output compare is enabled, the associated pin is configured automatically as an
output. If a pin is programmed as an output and input capture is enabled, the output data becomes
the input data to the input capture.
Bit 3 of Port J is a general purpose I/O pin and the data direction of the pin is determined by the state
of DDRJ bit 3. All DDRJ bits are cleared at reset.
4.12.1
Data Register (PORTJ)
$1031
7
6
5
4
3
2
1
0
0
0
0
0
PJ3
PJ2
PJ1
PJ0
RESET:
0
0
0
0
0
0
0
0
Alternate Pin Function:
—
—
—
—
—
O7/I6
O6/I5
TCK
PORTJ
READ:
Any time (inputs return pin levels, outputs return pin driver input levels).
WRITE:
Data stored in an internal latch (drives pins only if configured as outputs).
RESET:
General purpose high impedance inputs ($00).
4.12.2
Data Direction Register (DDRJ)
$1032
7
0
6
0
5
0
4
0
3
DDJ3
2
DDJ2
1
DDJ1
0
DDJ0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00 (all general purpose I/O configured for input only).
DDRJ
0 – Bits set to zero configure the corresponding I/O pins as inputs.
1 – Bits set to one configure the corresponding I/O pins as outputs.
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-11
Note:
4.13
The timer forces the I/O state to be an output if output compare 6 is enabled on Port J
bit 1 (OM6 or OL6 is a 1 and I5/O6 is a 0). The timer also forces the I/O state to be an
output if output compare 7 is enabled on Port J bit 2 (OM7 or OL7 is a 1 and I6/O7 is a
0). In this case, the data direction bit is not changed but has no effect on this line. The
DDRJ bit will revert to controlling the I/O state of the pin when timer output compare 6 is
disabled. TCK does not force the state of the line associated with it.
EXPANDED BUS (PORTS B, C, F)
The MC68HC11G5 has a non-multiplexed expansion bus. This simplifies system design, as
demultiplexing circuitry is not required. It also eliminates the need for an address strobe line.
The user gains three additional ports when the part is used in single chip mode. Port B provides the
high order addresses in expanded mode, but may be used as a general purpose output port in single
chip mode. Similarly, Port F provides the low order addresses, but may be used as a general purpose
output port in single chip mode. Port C is the data bus in expanded mode, but may be used as general
purpose I/O in single chip mode. Port C has a data direction register for use in single chip mode.
In order to allow emulation of all MC68HC11G5 functions, even in the expanded modes, the
functions displaced by specification of the expanded mode become externally addressed functions.
The registers which become external accesses are PORTC, DDRC, PORTB and PORTF.
4.13.1
R/W
The read/write output signal (R/W) is a dedicated function when the MC68HC11G5 is in normal
expanded mode or test mode. The timing of this signal is the same as the timing for a Port B address
output, except for the hold time from the falling edge of E, which is extended so that no special
circuitry is needed in a multi-board expanded system. This output reflects the state of the internal
CPU R/W signal.
In the single chip and bootstrap modes, the R/W pin is a dedicated output which is always high
(read). This permits changing from one of these modes to an expanded mode, without the risk that
the R/W line might have been in the “write” state, causing bus conflicts or inadvertent external
memory changes.
MOTOROLA
4-12
INPUT/OUTPUT PORTS
MC68HC11G5
4.13.2
Memory Ready (MRDY)
A memory ready function is available on the MC68HC11G5. This allows interfacing to slow
peripherals and dual ported RAM, and to dynamic RAM without a hidden refresh.
When the memory ready function is enabled, MRDY is used to stretch the CPU timing and E-clock
to allow a longer access time. Note that internal clocks to timers and baud rate generators continue
to run at the normal rate so that the timer and serial systems are not affected.
Port H bit 7 is used as the memory ready line (MRDY). When this line is low, an external access will
be stretched until the line goes high. During the stretch time the address lines will be held and
E will be kept in the high state. For write operations the data will be held and for read operations the
data bus lines will be inputs. When MRDY goes high, E will fall thus ending the cycle, and
will continue at a normal rate until the next external access during which MRDY is low. Note that the
bus will only stretch for integral numbers of E-clock cycles.
4.13.3
Options Register 2 (OPT2)
$1038
7
GWOM
6
CWOM
5
0
4
IRV
3
0
2
0
1
MRDY
0
NHALT
RESET:
0
0
0
—
0
0
0
1
OPT2
GWOM — PORT G Wired-Or Mode
READ:
Any time.
WRITE:
Any time.
0 – Port G operates normally.
1 – Port G outputs are open drain (used to facilitate testing).
CWOM — PORT C Wired-Or Mode
READ:
Any time.
WRITE:
Any time.
0 – Port C operates normally.
1 – Port C outputs are open drain (used to facilitate testing).
MC68HC11G5
INPUT/OUTPUT PORTS
MOTOROLA
4-13
IRV — Internal Read Visibility
READ:
Any time.
WRITE:
If SMOD=1, any time. If SMOD=0, only one write is allowed.
RESET:
Test and bootstrap modes – 1; single chip and expanded modes – 0.
0 – No visibility of internal reads on external bus.
1 – Data from internal reads is driven out on the external data bus.
MRDY — Memory Ready Enable
READ:
Any time.
WRITE:
Any time.
0 – Memory Ready is disabled, Port H bit 7 is general purpose I/O.
1 – Memory Ready is enabled, Port H bit 7 is forced to be an input used as the MRDY
line. External bus accesses will be stretched as long as this line is held low.
NHALT — Enable Halt Function
READ:
Any time
WRITE:
Any time
0 – Halt enabled (a logic low level detected on the HALT pin will cause the part to go
into the HALT state at the completion of the present instruction).
1 – Halt disabled.
MOTOROLA
4-14
INPUT/OUTPUT PORTS
MC68HC11G5
SECTION 5
RESETS, INTERRUPTS AND LOW POWER MODES
This section describes the internal and external resets and interrupts of the MC68HC11G5 and its
two low power consumption modes.
5.1
RESETS
The MCU can be reset in four ways:
1.
An active-low input to the RESET pin
2.
A power-on-reset function
3.
A clock monitor failure
4.
A computer operating properly (COP) watchdog timer timeout
The RESET input circuitry includes a Schmitt trigger which senses the RESET line logic level.
5.1.1
RESET Pin
The RESET pin is used to reset the MCU and allow an orderly software startup procedure. When
a reset condition is sensed, this pin is driven low by an internal device for four E-clock cycles, then
released, and two E-clock cycles later it is sampled. If the pin is still low, it means that an external
reset has occurred. If the pin is high, it implies that the reset was initiated internally by either the
watchdog timer (COP) or the clock monitor. This method of differentiation between internal and
external reset conditions assumes that the reset pin will rise to a logic one in less than two E-clock
cycles once it is released, and that an externally generated reset should stay active for at least eight
E-clock cycles.
5.1.2
Power-on-reset (POR)
Power-on-reset occurs when a positive transition is detected on VDD. This reset is used strictly for
power turn-on conditions and should not be used to detect any drop in the power supply voltage.
If the external RESET pin is low at the end of the power-on-reset delay time, the processor remains
in the reset state until RESET goes high.
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-1
5.1.3
Computer Operating Properly (COP) Reset
The MCU contains a watchdog timer which automatically times out unless it is reset within a specific
time by a program reset sequence. If the COP watchdog timer is allowed to timeout, a reset is
generated which drives the RESET pin low to reset the MCU and the external system.
The COP reset function can be enabled by programming the NOCOP control bit in the system
configuration register (CONFIG). Once programmed, this control bit remains set (or cleared), even
when no power is applied, and the COP function is enabled or disabled independent of resident
software. Protected control bits CR0 and CR1 in the configuration options register (OPTION) allow
the user to select one of four COP timeout periods. Table 5-1 shows the relationship between CR0
and CR1 and the timeout period for various system clock frequencies.
Table 5-1. COP Timeout Periods
23
15
XTAL = 2
XTAL = 8.0 MHz
E ÷2
CR1 CR0 Divided
Timeout
Timeout
– 0 / +15.6 ms – 0 / +16.4 ms
By
0
0
0
1
1
16.384 ms
XTAL =
XTAL = 4.0 MHz
4.9152 MHz
Timeout
Timeout
– 0 / +32.8 ms
– 0 / +26.7 ms
26.667 ms
32.768 ms
XTAL =
3.6864 MHz
Timeout
– 0 / +35.6 ms
1
15.625 ms
35.556 ms
1
4
62.5 ms
65.536 ms
106.67 ms
131.07 ms
142.22 ms
0
16
250 ms
262.14 ms
426.67 ms
524.29 ms
568.89 ms
1
64
1s
1.049 s
1.707 s
2.1 s
2.276 s
E=
2.1 MHz
2.0 MHz
1.2288 MHz
1.0 MHz
921.6 kHz
The sequence for resetting the watchdog timer is as follows:
1) Write $55 to the COP reset register (COPRST)
2) Write $AA to the COP reset register (COPRST)
Both writes must occur in this sequence prior to the timeout, but any number of instructions can be
executed between the two writes.
5.1.4
Clock Monitor Reset
The MCU contains a clock monitor circuit which measures the E-clock frequency. The clock monitor
function is enabled by the CME control bit in the OPTION register. Upon detection of a slow or absent
clock, the clock monitor circuit (if enabled by CME = 1) will cause a system reset to be generated.
If the E-clock input rate is above approximately 200 kHz, then the clock monitor does not generate
a reset. If the E-clock is lost or its frequency falls below 10 kHz, then a reset is generated, and the
RESET pin is driven low to reset the external system.
MOTOROLA
5-2
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
Special considerations are needed when using STOP and the clock monitor in the same system.
Since the STOP function causes the clocks to be halted, the clock monitor function will generate a
reset sequence if it is enabled prior to the STOP mode being entered. For systems which do not
expect or want a STOP function, this interaction can be useful to detect the unauthorized execution
of a STOP instruction which could not be detected by the COP watchdog system. On the other hand,
in systems which utilise both the STOP and clock monitor functions, this interaction means that the
CME bit must be written to zero just prior to executing a STOP instruction and should be written back
to one as soon as the MCU resumes execution.
5.1.5
Configuration Options Register (OPTION)
The bits in this register control certain configuration options, most of which can be changed only
during the first 64 cycles after reset in normal operating modes.
$1039
7
ADPU
6
CSEL
5
IRQE
4
DLY
3
CME
2
0
1
CR1
0
CR0
RESET:
0
0
0
1
0
0
0
0
OPTION
READ:
Any time.
WRITE:
Bits 3, 6, and 7 may be written at any time.
Bits 0, 1, 4, and 5 may be written once only in the normal operating modes, and only
during the first 64 cycles after reset. After this time the bits are read-only in the normal
operating modes (SMOD = 0). In the special test and bootstrap modes (SMOD = 1),
writes are always permitted.
RESET:
$10.
ADPU — A/D Power Up
0 – A/D system powered down to save supply current.
1 – A/D system powered up (allow about 100 µs for stabilization).
CSEL — Clock Select
This bit should be set to one if the E-clock is less than 1 MHz.
0 – A/D uses the system E-clock (must be 1.0 MHz or greater).
1 – A/D uses an internal R-C clock source (about 1.5 MHz).
IRQE — IRQ Select Edge Sensitive Only
0 – IRQ configured for low level recognition.
1 – IRQ configured to respond only to falling edges.
DLY — Enable Oscillator Start-up delay on exit from STOP
0 – No stabilization delay imposed on exit from STOP mode.
1 – A stabilization delay is imposed before processing resumes after STOP.
This bit is set during reset and controls whether or not a relatively long stabilization delay
is imposed before processing can resume after a STOP period. If an external clock signal
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-3
is supplied, this delay can be inhibited so that processing can be resumed within a few
cycles of a wake-up from STOP mode. When DLY is set, a 4064 E-clock cycle delay is
imposed to allow oscillator stabilization.
CME — Clock Monitor Enable
0 – Clock monitor disabled; a slow clock may be used.
1 – Slow or stopped clocks will cause a clock failure reset sequence.
In order to use both STOP and the clock monitor, the CME bit should be written to zero
prior to executing a STOP instruction and rewritten to one after recovery from STOP.
CR1 and CR0 — COP Timer Rate select bits
The COP system is driven by a constant frequency of E divided by 215. CR1 and CR0
specify an additional divide-by factor to arrive at the COP timeout rate (see Table 5-1).
5.1.6
State After Reset
The MCU mode is a function of the state of the two mode select pins. Enable bits for the ROM and
the COP system are contained in the CONFIG register, which is initialized during reset, and are
dependent on the mode which has been selected. In the single chip, bootstrap and test modes, the
ROM is on; in expanded mode the ROM is off. In the single chip and expanded modes the COP is
on; in bootstrap and test modes the COP is off.
The remainder of the system configuration is controlled via registers. Most of these registers and
control bits are forced to a specific state during reset. If a user requires a different configuration, he
must write different information into these registers.
Most of the configuration state after reset is independent of the MCU mode selected. Those features
which are specifically dependent on the mode are described in the following paragraphs.
CPU — The CPU fetches the restart vector from $FFFE, $FFFF ($BFFE, $BFFF in bootstrap mode
or test mode) during the first two cycles after reset and begins executing instructions. The stack
pointer and other CPU registers are indeterminate immediately after reset, except for the X and I
interrupt mask bits in the CCR, which are set so that interrupt requests will be masked, and the S
bit, also in the CCR, which is set so that the STOP instruction is disabled.
Memory Map — Immediately after reset the internal memory map of the MC68HC11G5 has 16
kilobytes of ROM located at the top of memory from $C000 – $FFFF (except in expanded mode
where the ROM is disabled and these bytes are external accesses), 512 bytes of RAM located at
the bottom of memory ($0000 – $01FF) and 128 bytes of internal register and I/O space located at
($1000 – $107F). If the bootstrap mode is selected, the memory map is the same except for the
addition of a small internal bootstrap ROM which is located at $BF00 – $BFFF. When a vector fetch
occurs in bootstrap mode, the A14 bit is forced low so that the vectors in the bootstrap ROM are
selected. In the test mode, A14 is also forced low during vector fetches but the bootstrap ROM is
not enabled so vectors are fetched from external memory located at $BFC0 – $BFFF.
Parallel I/O — If reset in an expanded mode, the pins used by the parallel I/O functions are dedicated
to the expansion bus and the parallel I/O functions become externally accessed functions to allow
emulation. If reset in single chip mode, the CWOM bit is initialized to zero (Port C not wired-OR
MOTOROLA
5-4
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
mode). Port C is initialized as an input port (DDRC = $00). Ports B and F are general purpose output
ports with all bits initialized to zero. R/W outputs a logic high level all the time. Ports A, D, G, H, and
J are configured as general purpose high-impedance inputs. Port E pins are configured as inputs.
Timer — The timer system is initialized during reset to a count of $0000. The prescaler bits are
cleared (to zero) so that the count rate equals the E-clock rate. All output compare registers are
initialized to $FFFF to guarantee the maximum time before any successful compare. All input
capture registers are indeterminate after reset. The OC1M register is cleared so successful OC1
compares will not affect any I/O pins. The other output compare functions are configured so as not
to affect any I/O pins on successful compares. All input capture edge detector circuits are configured
for “capture disabled” operation. The timer overflow interrupt flag and all timer function interrupt flags
are cleared and all timer interrupts are disabled by their mask bits being cleared.
Real Time Interrupt — The real time interrupt flag is cleared and automatic hardware interrupts are
masked by the RTII bit being clear. The rate control bits RTR1, RTR0 are cleared to zero, thus
selecting the shortest real time interrupt period.
Pulse Accumulator — The pulse accumulator system is disabled at reset. The PAIF and PAOVF
flags are cleared to indicate no pulse accumulator interrupts pending. The PAII and PAOVI interrupt
enable bits are cleared to inhibit pulse accumulator interrupts.
COP — The COP watchdog system is enabled if the NOCOP control bit is a zero and disabled if
NOCOP is one. The COP rate is set for the shortest duration timeout. If a different rate is required
then it must be initialized within 64 E-clock cycles after reset.
SCI Serial I/O — The reset condition of the SCI system is independent of the operating mode. At
reset, the SCI baud rate is indeterminate and must be established by a software write to the BAUD
register (note that in bootstrap mode software in the bootstrap ROM initializes the SCI system and
the baud rate). The frame format is configured for 8-bit data (M = 0). All transmit and receive
interrupts are masked and both the transmitter and receiver are disabled (turned off) so the port pins
associated with the SCI default to being general purpose I/O lines. The send break and receiver
wake-up functions are disabled. Although the wake-up function is disabled (RWU = 0), the WAKE
control bit is initialized to 0, thus selecting the ‘idle line’ mode of wake-up. The TDRE and TC status
bits are both set to one indicating that there is no transmit data in either the transmit data register
or the transmit serial shift register. The receiver related status bits RDRF, IDLE, OR, NF, and FE
are all cleared by reset.
SPI Serial I/O — The SPI system is disabled during reset. The port pins associated with this function
default to being general purpose I/O pins.
A to D — The A/D system is disabled by reset. Both the ADPU and CSEL bits are cleared to zero,
disabling the analog circuitry of the A/D and the internal R-C oscillator. The bits in the ADCTL control
register are indeterminate following reset. In any case, a write must be performed to this register in
order to initiate a conversion sequence.
System — The “Highest Priority I” interrupt defaults to the external interrupt pin IRQ by PSEL4 –
PSEL0 being set equal to 00110. The RBOOT, SMOD, and MDA bits in the HPRIO register reflect
the status of the MODB and MODA inputs at the rising edge of reset. The internal read visibility
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-5
control bit (IRV) in the OPT2 register is initialized to zero in normal modes to protect the system from
potential bus conflict with the external system. IRV is initialized to one if the MC68HC11G5 is reset
in a special mode (SMOD = 1) to enable internal read visibility for test and debug purposes. The IRQ
pin is configured for level sensitive operation (for wired-OR systems). The DLY control bit in the
OPTION register is set to specify that an oscillator start-up delay will be imposed upon recovery from
STOP mode. The clock monitor system is disabled by the CME bit in the OPTION register being set
to zero. When the system is reset in a special mode (SMOD = 1), the DISR control bit in the TEST1
register is initialized to logic one so that COP and clock monitor failures will not generate a reset.
In the normal modes (SMOD = 0), the DISR control bit is cleared to allow normal operation of the
COP and clock monitor systems.
5.2
INTERRUPTS
Excluding reset type interrupts, the MC68HC11G5 has 22 hardware interrupt sources and one
software interrupt source. These interrupts can be divided into two categories, maskable and nonmaskable. Twenty of the interrupt sources can be masked using the I bit in the condition code
register (CCR). All the on-chip hardware interrupts are individually masked by local control bits. The
software interrupt (SWI) is non-maskable. The external input to the XIRQ pin is considered a nonmaskable interrupt because it cannot be masked by software once it is enabled. However, it is
masked during reset and upon receipt of an interrupt signal at the XIRQ pin. Illegal opcode is also
a non-maskable interrupt.
5.2.1
Interrupt Vector Assignments
In all normal operating modes the interrupt vectors are located at the top of the address space
($FFC0 through $FFFF). In the bootstrap mode the interrupt vectors are located at $BFC0 through
$BFFF so that they exist in the internal bootstrap ROM. In the special test mode the interrupt vectors
also reside at $BFC0 – $BFFF but the internal bootstrap ROM is disabled so vectors are fetched
from external memory.
Table 5-2 provides a list of the interrupts with a vector location in memory for each, as well as the
condition code register and control bits that mask each interrupt. Figure 5-1 shows the interrupt
stacking order.
MOTOROLA
5-6
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
Table 5-2. Interrupt Vector Masks and Assignments
Vector
Address
Interrupt Source
Masked
by
Priority
(1= High)
FFC0, FFC1
*
*
FFCA, FFCB
FFCC, FFCD
FFCE, FFCF
Reserved
*
*
Reserved
Event 2
Event 1
—
—
—
I Bit
I Bit
—
22
21
FFD0, FFD1
FFD2, FFD3
FFD4, FFD5
FFD6, FFD7
Timer Overflow 2
Timer OC7/IC6
Timer OC6/IC5
SCI Serial System
I Bit
I Bit
I Bit
I Bit
18
16
15
24
FFD8, FFD9
FFDA, FFDB
FFDC, FFDD
FFDE, FFDF
SPI Serial Transfer Complete
Pulse Accumulator Input Edge
Pulse Accumulator Overflow
Timer Overflow 1
I Bit
I Bit
I Bit
I Bit
23
20
19
17
FFE0, FFE1
FFE2, FFE3
FFE4, FFE5
FFE6, FFE7
Timer OC5/IC4
Timer Output Compare 4
Timer Output Compare 3
Timer Output Compare 2
I Bit
I Bit
I Bit
I Bit
14
13
12
11
FFE8, FFE9
FFEA, FFEB
FFEC, FFED
FFEE, FFEF
Timer Output Compare 1
Timer Input Capture 3
Timer Input Capture 2
Timer Input Capture 1
I Bit
I Bit
I Bit
I Bit
10
9
8
7
FFFO, FFF1
FFF2, FFF3
FFF4, FFF5
FFF6, FFF7
Real Time Interrupt
IRQ (external pin)
XIRQ pin ( pseudo NMI)
SWI
I Bit
I Bit
X Bit
none
6
5
4
*
FFF8, FFF9
FFFA, FFFB
FFFC, FFFD
FFFE, FFFF
Illegal Opcode Trap
COP Failure (Reset)
COP Clock Fail Monitor (Reset)
RESET
none
none
none
none
*
3
2
1
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-7
STACK
SP
PCL
SP – 1
PCH
SP – 2
IYL
SP – 3
IYH
SP – 4
IXL
SP – 5
IXH
SP – 6
ACCA
SP – 7
ACCB
SP – 8
CCR
SP – 9
– SP Before Interrupt
– SP After Interrupt
Figure 5-1. Interrupt Stacking Order
5.2.2
Software Interrupt (SWI)
SWI is an instruction rather than a prioritized asynchronous interrupt source. It is non-maskable. In
one sense it is lower in priority than any source, because once an interrupt sequence has begun,
SWI cannot override it. In another sense, it is higher in priority than any source except reset, because
once the SWI opcode is fetched, no other source can be serviced until after the first instruction in
the SWI service routine has been executed. SWI causes the I mask bit in the CCR to be set.
5.2.3
Illegal Opcode Trap
Since not all possible opcodes or opcode sequences are defined, an illegal opcode detection circuit
has been included in the MC68HC11G5. When an illegal opcode is detected, an interrupt is
requested to the illegal opcode vector. It is non-maskable and the illegal opcode vector should never
be left uninitialized.
5.2.4
Real Time Interrupt
The real time interrupt (or periodic interrupt) feature on the MC68HC11G5 is configured and
controlled by three bits in the PACTL register (RTR2, RTR1 and RTR0 which select one of six
interrupt rates based on the MCU E-clock), an interrupt status flag (RTIF) in the TFLG2 register, and
a mask bit (RTII) in the TMSK2 register (which enables/inhibits hardware interrupts based on the
RTIF flag bit). After reset, one entire real time interrupt period will elapse before the RTIF flag gets
set for the first time. (See SECTION 6: PROGRAMMABLE TIMER, REAL TIME INTERRUPT AND
PULSE ACCUMULATOR for more information on the real time interrupt.)
MOTOROLA
5-8
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
5.2.5
Interrupt Mask Bits in Condition Code Register
On reset, both the X bit and the I bit in the CCR are set to inhibit all maskable interrupts and XIRQ.
After minimum system initialization, software may clear the X bit by a TAP instruction, thus enabling
XIRQ interrupts. Thereafter, software cannot set the X bit. Thus, an XIRQ is effectively a nonmaskable interrupt. Since the operation of the I bit related interrupt structure has no effect on the
X bit, the internal XIRQ pin remains effectively non-masked. In the interrupt priority logic, the XIRQ
interrupt is a higher priority than any source that is maskable by the I bit. All I bit related interrupts
operate normally with their own priority relationships.
When an I bit related interrupt occurs, the I bit is automatically set by hardware after stacking the
CCR byte. The X bit is not affected. When an X bit related interrupt occurs, both the X and the I bit
are automatically set by hardware after stacking the CCR byte. A return from interrupt (RTI)
instruction restores the X and I bits to their pre-interrupt request state.
5.2.6
Priority and Masking Structure
Interrupts obey a fixed hardware priority circuit to resolve simultaneous requests. However, one I bit
related interrupt source may be elevated to the highest I bit priority position in the resolution circuit.
Six interrupt sources are not masked by the I bit in the condition codes register and have the fixed
priority relationship:
1.
Reset
2.
Clock failure monitor
3.
COP failure
4.
Illegal opcode
5.
SWI
6.
XIRQ
SWI is actually an instruction and has highest priority other than reset in the sense that once the SWI
opcode is fetched, no other interrupt can be honoured until after the first instruction in the SWI
service routine has been executed. The scenario is similar for the illegal opcode.
Each of these sources is an input to the priority resolution circuit. The highest I bit masked priority
input to the resolution circuit is assigned under software control (via the HPRIO register) to be
connected to any one of the remaining I bit related interrupt sources. In order to avoid timing races
the HPRIO register may only be written while the I bit related interrupts are inhibited (I bit in CCR
set). An interrupt which is assigned to this high priority position is still subject to masking by any
associated control bits or by the I bit in the CCR. The address from which the interrupt vector is
fetched is not affected by assigning a source to this higher priority position.
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-9
All interrupt sources from on-chip peripherals have software programmable interrupt mask bits
which may be used to selectively inhibit automatic hardware response to each interrupt source. In
addition the X and I bits in the condition code register act as class inhibit masks to inhibit all sources
in the X bit and/or I bit class. Figures 5-2, 5-3 and 5-4 summarize the priority structure and additional
mask conditions that lead to the recognition of interrupt requests in the MC68HC11G5.
HIGHEST
POWER-ON RESET
(POR)
PRIORITY
EXTERNAL RESET
DELAY 4064 E CYCLES
CLOCK MONITOR FAIL
(WITH CME = 1)
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFE, FFFF (VECTOR FETCH)
LOWEST
COP WATCHDOG
TIMEOUT
(WITH NOCOP = 0)
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFC, FFFD (VECTOR FETCH)
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFA, FFFB (VECTOR FETCH)
SET S, X, AND I BITS
IN CCR
RESET MCU
HARDWARE
1A
BEGIN AN INSTRUCTION
SEQUENCE
YES
X BIT
IN CCR
SET ?
NO
XIRQ PIN
LOW ?
NO
YES
STACK CPU
REGISTERS
SET X AND I BITS
FETCH VECTOR
$FFF4, FFF5
1B
Figure 5-2. Processing Flow out of Resets
MOTOROLA
5-10
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
1B
YES
I BIT
IN CCR
SET ?
NO
ANY I BIT
INTERRUPT
PENDING
?
NO
YES
FETCH OPCODE
STACK CPU
REGISTERS
NO
STACK CPU
REGISTERS
LEGAL
OPCODE
?
SET X AND I BITS
FETCH VECTOR
$FFF8, FFF9
YES
YES
WAI ?
STACK CPU
REGISTERS
NO
YES
STACK CPU
REGISTERS
NO
SWI ?
SET X AND I BITS
FETCH VECTOR
$FFF6, FFF7
YES
NO
YES
INTERRUPT
YET ?
SET I BIT
RTI ?
RESTORE CPU
REGISTERS
FROM STACK
NO
EXECUTE THIS
INSTRUCTION
1A
RESOLVE INTERRUPT
PRIORITY AND FETCH
VECTOR FOR HIGHEST
PENDING SOURCE
(SEE FIGURE 5-3)
START NEXT
INSTRUCTION
SEQUENCE
Figure 5-2. Processing Flow out of Resets (contd)
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-11
BEGIN
X BIT
IN CCR
SET ?
YES
NO
XIRQ PIN
LOW ?
YES
NO
HIGHEST
PRIORITY
INTERRUPT
?
NO
IRQ ?
YES
SET X BIT IN CCR
FETCH VECTOR
$FFF4, FFF5
FETCH VECTOR
YES
FETCH VECTOR
$FFF2, FFF3
NO
RTII = 1 ?
YES
NO
REAL-TIME
INTERRUPT
?
YES
FETCH VECTOR
$FFF0, FFF1
YES
FETCH VECTOR
$FFEE, FFEF
YES
FETCH VECTOR
$FFEC, FFED
YES
FETCH VECTOR
$FFEA, FFEB
YES
FETCH VECTOR
$FFE8, FFE9
YES
FETCH VECTOR
$FFE6, FFE7
YES
FETCH VECTOR
$FFE4, FFE5
YES
FETCH VECTOR
$FFE2, FFE3
NO
IC1I = 1 ?
YES
NO
TIMER
IC1F ?
NO
IC2I = 1 ?
YES
NO
TIMER
IC2F ?
NO
IC3I = 1 ?
YES
NO
TIMER
IC3F ?
NO
OC1I = 1 ?
YES
NO
TIMER
OC1F ?
NO
OC2I = 1 ?
YES
NO
TIMER
OC2F ?
NO
OC3I = 1 ?
YES
NO
TIMER
OC3F ?
NO
OC4I = 1 ?
NO
YES
TIMER
OC4F ?
NO
2A
2B
Figure 5-3. Interrupt Priority Resolution
MOTOROLA
5-12
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
2A
2B
4/5I = 1 ?
YES
NO
YES
FETCH VECTOR
$FFE0, FFE1
YES
FETCH VECTOR
$FFD4, FFD5
YES
FETCH VECTOR
$FFD2, FFD3
YES
FETCH VECTOR
$FFDE, FFDF
YES
FETCH VECTOR
$FFD0, FFD1
YES
FETCH VECTOR
$FFDC, FFDD
YES
FETCH VECTOR
$FFDA, FFDB
YES
FETCH VECTOR
$FFCE, FFCF
YES
FETCH VECTOR
$FFCC, FFCD
YES
FETCH VECTOR
$FFD8, FFD9
NO
5/6I = 1 ?
YES
NO
TIMER
5/6F ?
NO
6/7I = 1 ?
YES
NO
TIMER
6/7F ?
NO
TO1I = 1 ?
YES
NO
TIMER
TO1F ?
NO
TO2I = 1 ?
YES
NO
TIMER
TO2F ?
NO
PAOVI = 1 ?
YES
NO
PULSE
ACCUMULATOR
PAOVF ?
NO
PAII = 1 ?
YES
NO
PULSE
ACCUMULATOR
PAIF ?
NO
EV1I = 1 ?
YES
NO
EVENT
COUNTER
EV1F ?
NO
EV2I = 1 ?
YES
NO
EVENT
COUNTER
EV2F ?
NO
SPIE = 1 ?
YES
NO
SPIF OR
MODF ?
NO
SCI SERIAL ?
(SEE FIGURE
5-4)
NO
TIMER
4/5F ?
YES
SPURIOUS INTERRUPT — TAKE IRQ VECTOR
FETCH VECTOR
$FFD6, FFD7
FETCH VECTOR
$FFF2, FFF3
END
Figure 5-3. Interrupt Priority Resolution (contd)
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-13
BEGIN
RDRF = 1 ?
YES
NO
OR = 1 ?
YES
NO
TDRE = 1 ?
YES
NO
TIE = 1 ?
YES
TCIE = 1 ?
RE = 1 ?
YES
NO
YES
NO
NO
IDLE = 1 ?
YES
NO
NO
TC = 1 ?
RIE = 1 ?
TE = 1 ?
YES
NO
YES
NO
YES
ILIE = 1 ?
NO
YES
RE = 1 ?
YES
NO
NO VALID SCI
REQUEST
YES — VALID SCI
REQUEST
Figure 5-4. Interrupt Source Resolution within SCI
MOTOROLA
5-14
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
5.2.7
“Highest Priority I” Interrupt and Miscellaneous Register (HPRIO)
$103C
7
RBOOT
6
SMOD
5
MDA
4
PSEL4
3
PSEL3
2
PSEL2
1
PSEL1
0
PSEL0
RESET:
—
—
—
0
0
1
1
0
HPRIO
RBOOT — Read Bootstrap ROM
READ:
Any time.
WRITE:
Only while SMOD = 1 (test or bootstrap modes).
RESET:
Set in Bootstrap mode, cleared in all other modes.
0 – Bootstrap ROM disabled and not in memory map.
1 – Bootstrap ROM enabled in memory map at $BF00 through $BFFF.
SMOD and MDA — Special Mode Select and Mode Select A
READ:
Any time.
WRITE:
SMOD may only be written to a 0. MDA may be written any time while SMOD =
1, but MDA may only be written once while SMOD = 0.
RESET:
These bits reflect the status of the MODB and MODA input pins at the rising
edge of reset.
An interpretation of the values of SMOD and MDA is shown in Table 5-3.
Note:
SMOD cannot be written to a logic one after being cleared.
Table 5-3. Special Mode Select and Mode Select A Table
Input Pins
Latched at Reset
MODA
MODB
0
1
1
SMOD
MDA
Single Chip
0
0
1
Expanded Non-Multiplexed
0
1
0
0
Bootstrap
1
0
1
0
Test
1
1
MC68HC11G5
Mode Selected
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-15
PSEL4, PSEL3, PSEL2, PSEL1, PSEL0 — Priority Select bits 4 – 0
READ:
Any time.
WRITE:
Only while I bit in CCR is set (interrupts inhibited).
These five bits are used to specify one I bit related interrupt source which will become
the highest priority I bit related source (see Table 5-4).
Table 5-4. Priority Select Bits Table
PSEL4 PSEL3 PSEL2 PSEL1 PSEL0
Interrupt Source Promoted
0
0
0
X
X
Reserved (Default to IRQ)
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
Reserved (Default to IRQ)
Reserved (Default to IRQ)
IRQ (External pin or Parallel I/O)
Real Time Interrupt
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
1
0
1
Timer Input Capture 1
Timer Input Capture 2
Timer Input Capture 3
Timer Output Compare 1
0
0
0
0
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
1
Timer Output Compare 2
Timer Output Compare 3
Timer Output Compare 4
Timer OC5/IC4
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
Timer Overflow 1
Pulse Accumulator Overflow
Pulse Accumulator Input Edge
SPI Serial Transfer Complete
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
SCI Serial System
Timer OC6/IC5
Timer OC7/IC6
Timer Overflow 2
1
1
1
1
1
1
1
1
0
0
0
0
0
0
1
1
0
1
0
1
Event Counter 1
Event Counter 2
Reserved (Default to IRQ)
Reserved (Default to IRQ)
1
1
1
X
X
Reserved (Default to IRQ)
MOTOROLA
5-16
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
5.3
LOW POWER MODES
The MC68HC11G5 has a WAIT mode to suspend processing and reduce power consumption to an
intermediate level. The MC68HC11G5 also offers a STOP mode which turns off all on-chip
clocks and reduces power consumption to an absolute minimum while retaining the contents of all
512 bytes of RAM.
5.3.1
WAIT
WAIT mode is invoked by executing the WAI opcode. The CPU registers are stacked and
CPU processing is suspended until a qualified interrupt is detected. The interrupt can be an external
IRQ, an XIRQ, or any of the internally generated interrupts such as the timer or serial interrupts.
The on-chip crystal oscillator remains active throughout the WAIT standby period.
The reduction of power in WAIT mode depends on how many internal clock signals driving on-chip
peripheral functions can be shut down. The CPU is always shut down in WAIT mode. The freerunning timer system is shut down in WAIT mode if, and only if, the I bit is set to one and the
COP system is disabled by NOCOP being set to one. Several other systems may also be in a
reduced power consumption state depending upon the state of software controlled configuration
control bits. Power consumption by the A/D is not significantly affected by WAIT mode. However,
the A/D current can be eliminated by writing the ADPU bit to zero. The SPI system is enabled or
disabled by the SPE control bit. The SCI transmitter is enabled or disabled by the TE bit, and the
SCI receiver is enabled or disabled by the RE bit.
The power consumption in WAIT mode is very dependent, therefore, on the particular application.
5.3.2
STOP
STOP mode is invoked by executing the STOP instruction while the S bit in the CCR is equal to zero.
If the S bit is not zero then the STOP opcode is treated as a no-op (NOP). STOP mode offers
minimum power consumption because all clocks including the crystal oscillator are stopped while
in this mode. To exit the STOP mode and resume normal processing, a logic low level must be
applied to one of the external interrupts (IRQ or XIRQ) or to the RESET pin. A pending edgetriggered IRQ can also bring the CPU out of STOP mode.
Since all clocks are stopped in this mode, all internal peripheral functions also stop. The data in the
internal RAM is retained as long as VDD power is maintained. The CPU state and I/O pin levels are
static and are unchanged by the STOP mode. Therefore, when an interrupt comes to restart the
system, the MC68HC11G5 resumes processing as if there were no interruption. If reset is used to
restart the system a normal reset sequence results where all I/O pins and functions are also restored
to their initial states.
In order for the IRQ pin to be used as a means of recovering from the STOP mode, the I bit in the
CCR must be clear (IRQ not masked). The XIRQ input may be used to wake up the MCU from STOP
regardless of the state of the X bit in the CCR, although the recovery sequence depends on the state
of the X bit. If X is set to zero (XIRQ not masked), the MCU will start up beginning with the stacking
MC68HC11G5
RESETS, INTERRUPTS AND LOW POWER MODES
MOTOROLA
5-17
sequence leading to normal service of the XIRQ request. If X is set to one (XIRQ masked or
inhibited), then processing will continue with the instruction which immediately follows the STOP
instruction, and no XIRQ interrupt service will be requested or pending.
Since the oscillator is stopped in STOP mode, a restart delay may be imposed to allow oscillator
stabilization upon leaving the STOP mode. If the internal oscillator is being used, this delay is
required; however,if a stable external oscillator is being used, the DLY control bit may be used to
by-pass this start-up delay. The DLY control bit is set by reset and may be optionally cleared during
initialization. If the “DLY equal to zero” option is used to avoid start-up delay on recovery from STOP,
then reset should not be used as the means of recovering from STOP since this will cause DLY to
be set again by reset and the restart delay will be imposed. This same delay also applies to poweron-reset (regardless of the state of the DLY control bit) but does not apply to a reset while the clocks
are running.
MOTOROLA
5-18
RESETS, INTERRUPTS AND LOW POWER MODES
MC68HC11G5
SECTION 6
PROGRAMMABLE TIMER, REAL TIME INTERRUPT AND PULSE
ACCUMULATOR
This section describes the 16-bit programmable timer, the real time interrupt and the pulse
accumulator system.
In order to reduce the overhead required to service interrupts, the three timer overflows and the other
twelve timer functions each have their own interrupt vector, and each of these interrupts is
independently maskable.
6.1
PROGRAMMABLE TIMER
The timer system on the MC68HC11G5 has been derived from the original MC68HC11A8 timer.
There are four fixed output compares (OC), three fixed input captures (IC) and three programmable
input captures/output compares (IC/OC).
Secondly, there are two separate “time-of-day” type 16-bit free-running counters, each with its own
prescaler. The first counter is associated with the four fixed output compares and two of the
programmable input capture/output compares. The second counter is associated with the three
fixed input captures and one programmable input capture/output compare.
6.1.1
Counters
The two 16-bit counters (TCNT1 and TCNT2) are clocked by the outputs of separate 3-stage
prescalers (divide by 1, 2, 4, or 8) which are in turn driven by the MCU E-clock. (Note that these
prescaler values have been changed from the original MC68HC11A8 to include divide-by-2 and to
exclude divide-by-16.) The second counter can also be driven by an external clock instead of the
internal clock. An external clock cannot be used with counter 1 because this counter chain is also
used to time the real time interrupt and the COP circuit.
In addition, counter 2 can be cleared by software. This is accomplished by writing any value to the
counter register. This forces a hardware reset of the counter, regardless of the value written. This
feature is not available on counter 1 because counter 1 is also used to time the real time interrupt
and the COP circuit.
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-1
6.1.2
Prescalers
There are two prescalers, one for each of the timer counters. All of the prescaler select bits are
included in one register (TPRE). This allows the user to set both prescalers simultaneously so that
both counters may be kept synchronized. The external clock edge selects for counter 2 are also
included in this register.
Each prescaler is a 3-stage divider with the E-clock as its input, and each stage divides by two. The
prescaler output is selectable as E, E/2, E/4, or E/8. After reset, the MC68HC11G5 is configured to
use the E-clock as the input to both counters. Initialization software may optionally reconfigure
counter 1 to use one of the three prescale taps so that the E-clock is divided by 2, 4, or 8 before driving
the free running counter. Initialization software may, at the same time, optionally reconfigure counter
2 to use one of the three prescale taps so that the E-clock is divided by 2, 4, or 8 before driving the
free-running counter, and may select the falling, rising or both edges of an external clock. If counter
2 uses the external clock, then the prescaler bits have no effect.
6.1.3
Input Capture Functions
The fixed input capture registers (TIC1 – TIC3) are 16-bit read-only registers which are not affected
by reset and are used to latch the value of the free-running counter when a defined transition is
sensed by the corresponding input capture edge detector. They optionally cause an interrupt in
response to a detected edge event on an input pin. Pairs of bits in the TCTL2 register allow the user
to specify that input capture will occur on rising edges only, falling edges only, rising and falling edges
or to inhibit captures completely. Registers TMSK1 and TFLG1 provide interrupt enable and
interrupt flag bits, respectively Input captures IC1 – IC3 are associated with Port A, bits 2 – 0,
respectively.
6.1.4
Output Compare Functions
The fixed output compare registers (TOC1 – TOC4) are 16-bit read/write registers which are
initialized to $FFFF by reset and can be used for several purposes. Possible applications include
controlling an output waveform and indicating when a period of time has elapsed. The output
compare registers are unique in that all bits are readable and writable and are not altered by the timer
hardware (except during reset). If an output compare function is not utilized, the unused registers
may be used simply as storage locations. Output compares OC1 – OC4 are associated with
Port A bits 7 – 4, respectively.
The output compare functions referred to above cause an output action and/or an interrupt when
there is a match between a 16-bit output compare register and the free-running counter. At any time
the bits controlled by the output compare functions may be read to determine the current state of
the output pin.
Three of the fixed output compare functions (OC2, OC3 and OC4) and all of the programmable ones
allow software to specify that the corresponding output pin should toggle, be set to one, be cleared
to zero, or be disconnected from the output pin logic. This is controlled using the OMx and OML bits
in the timer control registers TCTL1 and TCTL3.
MOTOROLA
6-2
PROGRAMMABLE TIMER
MC68HC11G5
Unlike the other output compare functions, OC1 can automatically affect any or all of the Port A
output pins associated with OC2 – OC5 (with OC5/IC4 configured for output compare), as a result
of a successful compare between the OC1 register and the 16-bit free running counter. Two 5-bit
registers are used in conjunction with this function, the output compare 1 mask register (OC1M) and
the output compare 1 data register (OC1D). The OC1M register specifies bit-for-bit which Port A
lines (bits 3 – 7) are to be affected and the OC1D register specifies what data is to be placed on the
affected lines. By configuring the system so that both OC1 and another output compare function both
control the same output line, output pulses can be generated with durations as short as one free
running counter count.
Since the four other output compare functions (OC2 – OC5) optionally affect four bits of Port A and
the pulse accumulator optionally uses bit 7 of Port A, there is an overlap of these functions with the
OC1 output compare function. Pins are made available to the OC1 function when other timer
functions are not used or are used in a manner that does not require use of the I/O pin.
A write-only register (CFORC) is provided to allow the equivalent of a forced output compare
function. Writing a one to any bit in this register immediately has the same effect as a successful
comparison on the corresponding output compare function.
In some cases the values in the output compare register and the output action control bits must be
changed after each successful comparison to control an output waveform or to establish a new
elapsed timeout.
Due to the prescaler, the counter may not change value on each cycle of the E-clock and the
comparison may be true for several consecutive E-clock cycles. In order to avoid multiple output
actions, the output action is permitted to occur only during the E-clock low time immediately following
the cycle during which the match first became true.
An interrupt can also accompany a successful output compare provided that the corresponding
interrupt enable bit (OCxI) in the TMSK1 register is set. In this event, the corresponding interrupt
flag bit (OCxI) in the TFLG1 register will be set.
After writing to the TOCx register’s most significant byte, the output compare function is inhibited
for one E-clock cycle, to allow writing two consecutive bytes before making the next comparison.
If both bytes of the register are to be changed, a double byte write instruction should be used in order
to take advantage of the compare inhibit feature.
MPU writes can be made to either byte of the output compare register without affecting the other
byte. When a compare occurs, the output action is taken regardless of whether or not the output
compare flag (OCxF) was previously set.
6.1.5
Programmable Input Capture/Output Compares
There are three programmable input capture/output compares. Each channel has a 16-bit register
(TO5I4, TO6I5, TO7I6) associated with it which acts as either an output compare register or an
input capture register depending on which is specified. OC5/IC4 and OC6/IC5 are associated
with counter 1 and OC7/IC6 is associated with counter 2. The selection of output compare or
input capture for these functions is controlled by the I4/O5 bit in the PACTL register and the I5/O6
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-3
and I6/O7 bits in the TCTL4 register. Output compare actions are controlled by bits in TCTL1, TCTL3
and CFORC. Input capture control is via registers TCTL2 and TCTL3. Registers TMSK1 and TMSK2
provide interrupt enable bits for input capture and output compare functions. TFLG1 and TFLG2
provide corresponding interrupt flag bits.
6.2
REAL TIME INTERRUPT
The real time interrupt feature on the MC68HC11G5 is configured and controlled using three bits
(RTR2, RTR1 and RTR0) in the PACTL register to select one of eight interrupt rates. The RTII bit
in the TMSK2 register enables the interrupt capability. Every timeout causes the RTIF bit in TFLG2
to be set, and if RTII is set, an interrupt request is generated. After reset, one entire real time interrupt
period elapses before the RTIF flag is set for the first time.
6.3
PULSE ACCUMULATOR
The pulse accumulator is an 8-bit read/write counter (PACNT) which can operate in either of two
modes (external event counting or gated time accumulation) depending on the state of the PAMOD
control bit in the PACTL register. In the event counting mode, the 8-bit counter is clocked to
increasing values by an external pin input. The maximum clocking rate for the external event
counting mode is E divided by 2. In the gated time accumulation mode a free-running E/64 clock
drives the 8-bit counter, but only while the external PAI input pin is in a selected state.
Although Port A bit 7 would normally be configured as an input when being used for the pulse
accumulator, it still drives the pulse accumulator system even when it is configured for use in its other
functions. DDRA bit 7 controls the data direction of Port A bit 7. When DDRA bit 7 is zero, Port A
bit 7 is an input only pin, unless OC1 is configured to control the pin. When DDRA bit 7 is a one, Port
A bit 7 is an output but is still connected to the pulse accumulator input.
PAEN in the PACTL register enables/disables the pulse accumulator.
PEDGE in the PACTL register selects the active edge of the input signal on the PAI pin.
The PAOVF status bit in the TFLG2 register is set when the counter overflows from $FF to $00.
The PAOVI mask bit in the TMSK2 register controls whether or not a hardware interrupt will be
generated when the PAOVF flag bit is set.
The PAIF flag bit in the TFLG2 register is set when an active edge is detected on the PAI input pin.
The PAII mask bit in the TMSK2 register controls whether or not a hardware interrupt will be
generated when the PAIF status bit is set.
MOTOROLA
6-4
PROGRAMMABLE TIMER
MC68HC11G5
6.4
TIMER, RTI AND PULSE ACCUMULATOR REGISTERS
6.4.1
Count Registers (TCNT1 and TCNT2)
$100E
$100F
7
BIT15
BIT7
6
BIT14
BIT6
5
BIT13
BIT5
4
BIT12
BIT4
3
BIT11
BIT3
2
BIT10
BIT2
1
BIT9
BIT1
0
BIT8
BIT0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RESET:
READ:
Any time.
WRITE:
Has no effect for SMOD = 0; forces to $FFF8 for SMOD = 1.
RESET:
$0000.
$1052
$1053
7
BIT15
BIT7
6
BIT14
BIT6
5
BIT13
BIT5
4
BIT12
BIT4
3
BIT11
BIT3
2
BIT10
BIT2
1
BIT9
BIT1
0
BIT8
BIT0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RESET:
READ:
Any time.
WRITE:
Forces to $0000 for SMOD = 0; forces to $FFF8 for SMOD = 1.
RESET:
$0000.
TCNT1
TCNT2
TCNT1 is associated with OC1 – OC4, OC5/IC4 and OC6/IC5. Note thatdue to the periodic interrupt
and COP timer also using this counter as their clock source, an external clock cannot be used to
drive this timer counter.
TCNT2 is associated with IC1 – IC3 and OC7/IC6. This counter differs from counter 1 in two ways:
it can be driven by an external clock; and it can be reset under software control.
A full counter read should first address the most significant byte. Reading this address causes the
least significant byte to be latched into a buffer for the next CPU cycle so that a double byte read
will return the full 16-bit state of the counter at the time of the most significant byte read cycle. This
buffer is not affected by reset and is accessed when reading the least significant byte of the counter.
For double byte read instructions, these two accesses occur on consecutive bus cycles. The buffer
is transparent except for the cycle following a most significant byte read so that reads of the least
significant byte alone will return the current state of the counter. Software can read the counter at
any time without affecting its value. Note that the counter is clocked and read during opposite half
cycles of the E-clock.
Both counters are cleared to $0000 during reset. In the normal operating modes (SMOD = 0), writing
to TCNT2 causes TCNT2 to be reset to $0000, whereas writing to TCNT1 has no effect. In the test
and bootstrap modes only (SMOD = 1), any write to either counter’s most significant byte causes
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-5
the counter to be preset to $FFF8 regardless of the data written. This preset capability is intended
only for factory testing.
Because its width is 16 bits, the value in the free running counter repeats every 65,536 counts
(prescaler timeouts). When the count changes from $FFFF to $0000 the timer overflow flag bit
(TOxF), in the TFLG2 register, is set. A timer overflow interrupt can be enabled by setting its interrupt
enable bit (TOxI), in the TMSK2 register.
6.4.2
Prescaler Register (TPRE)
$1058
7
TEDGB
6
TEDGA
5
PR2B
4
PR2A
3
0
2
0
1
PR1B
0
PR1A
RESET:
0
0
0
0
0
0
0
0
TPRE
READ:
Any time.
WRITE:
If SMOD = 0, may be written only once during the first 64 cycles. After this time, the bits
become read-only. If SMOD = 1, writing is always permitted.
TEDGB, TEDGA — Timer External Clock Edge Select
These two bits determine which edge(s) of the external clock will cause timer counter 2
to increment. The external clock comes in via Port J, bit 0.
Note:
TEDGB
TEDGA
Configuration
0
0
Counter 2 uses the internal clock and
prescaler
0
1
Count on rising edges only
1
0
Count on falling edges only
1
1
Count on any edge (rising or falling)
the maximum frequency of the input clock must be less than E/2 when counting on
only rising or falling edges and must be less than E/4 when counting on both edges.
MOTOROLA
6-6
PROGRAMMABLE TIMER
MC68HC11G5
PR2B, PR2A — Timer Prescaler Select
These bits specify the number of divide-by-2 stages to be inserted between the E-clock
and timer counter 2. Note: these bits have no effect if the external clock is selected
(TEDGB or TEDGA = 1).
PR2B
PR2A
Prescale Factor
0
0
1
0
1
2
1
0
4
1
1
8
PR1B, PR1A — Timer Prescaler select
These bits specify the number of divide-by-2 stages to be inserted between the E-clock
and timer counter 1.
6.4.3
PR1B
PR1A
Prescale Factor
0
0
1
0
1
2
1
0
4
1
1
8
Input Capture Registers (TIC1 – TIC3)
7
6
5
4
3
2
1
0
$1010
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1011
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
$1012
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1013
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
$1014
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1015
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
MC68HC11G5
PROGRAMMABLE TIMER
TIC1
TIC2
TIC3
MOTOROLA
6-7
READ:
Any time.
WRITE:
Has no meaning or effect.
RESET:
Indeterminate (not initialized).
These registers are used to latch the value of timer counter 2 when a defined transition is sensed
by the corresponding input capture edge detector. The result obtained by an input capture
corresponds to the value of the counter one cycle after the transition which triggered the edge
detection logic. This delay is required for internal synchronization.
After a read of the most significant byte of the register, counter transfer is inhibited during the next
E-clock cycle. During double byte reads, this inhibited transfer will occur between consecutive read
cycles of the most and least significant bytes.
6.4.4
Output Compare Registers (TOC1 – TOC4)
7
6
5
4
3
2
1
0
$1016
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1017
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
$1018
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1019
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
$101A
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$101B
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
$101C
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$101D
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
READ:
Any time.
WRITE:
Any time.
RESET:
$FFFF
TOC1
TOC2
TOC3
TOC4
A write to a high order byte inhibits the compare for the next E-clock cycle. When the TOCx register
matches the TCNT1 register, the OCxF bit in the TFLG1 register is set and the specified output
action takes place.
All output compare registers have a separate dedicated comparator for comparing against the free
running counter. If a match is found, the corresponding output compare flag bit (OCxF) is set and
a specified action is automatically taken.
For output compare functions OC2, OC3 and OC4, the automatic action is controlled by pairs of bits
in the TCTL1 control register. Each pair of control bits is encoded to specify the output action to be
taken as a result of a successful OCx compare. Output compare functions OC2, OC3 and OC4 are
always associated with Port A bits 6 – 4 respectively.
MOTOROLA
6-8
PROGRAMMABLE TIMER
MC68HC11G5
6.4.5
Output Compare 5/Input Capture 4 Register (TO5I4)
This is a shared register which acts as the output compare OC5 register or as the input capture IC4
register depending on the state of the I4/O5 bit in the PACTL register. This register is associated
with timer counter 1 and with Port A, bit 3.
7
6
5
4
3
2
1
0
$101E
$101F
BIT15
BIT7
BIT14
BIT6
BIT13
BIT5
BIT12
BIT4
BIT11
BIT3
BIT10
BIT2
BIT9
BIT1
BIT8
BIT0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time this register is configured for OC operation.
RESET:
$FFFF
6.4.6
TO5I4
Output Compare 6/Input Capture 5 Register (TO6I5)
This is a shared register which acts as the output compare OC6 register or as the input capture IC5
register depending on the state of the I5/O6 bit in the TCTL4 register. This register is associated with
timer counter 1 and with Port J, bit 1.
7
6
5
4
3
2
1
0
$1054
$1055
BIT15
BIT7
BIT14
BIT6
BIT13
BIT5
BIT12
BIT4
BIT11
BIT3
BIT10
BIT2
BIT9
BIT1
BIT8
BIT0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time this register is configured for OC operation.
RESET:
$FFFF
MC68HC11G5
PROGRAMMABLE TIMER
TO6I5
MOTOROLA
6-9
6.4.7
Output Compare 7/Input Capture 6 Register (TO7I6)
This is a shared register which acts as the output compare OC7 register or as the input capture IC6
register depending on the state of the I6/O7 bit in the TCTL4 register. This register is associated with
timer counter 2 and with Port J, bit 2.
7
6
5
4
3
2
1
0
$1056
$1057
BIT15
BIT7
BIT14
BIT6
BIT13
BIT5
BIT12
BIT4
BIT11
BIT3
BIT10
BIT2
BIT9
BIT1
BIT8
BIT0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time this register is configured for OC operation.
RESET:
$FFFF
TO7I6
There are both input control bits and output control bits associated with these functions. Only the bits
associated with the selected function (input or output) will affect the operation of the timer channel.
6.4.8
Output Compare 1 Action Mask Register (OC1M)
$100C
7
OC1M7
RESET:
0
6
5
4
3
OC1M6 OC1M5 OC1M4 OC1M3
0
0
0
0
2
0
1
0
0
0
0
0
0
READ:
Any time (bits 2 through 0 always return 0).
WRITE:
Any time (writes to bits 2 through 0 have no meaning or effect).
RESET:
$00 (OC1 disconnected from Port A logic).
OC1M
OC1M is used to specify which bits of Port A (I/O and timer port) are to be affected as a result of a
successful OC1 compare. The bits of OC1M correspond bit-for-bit with the bits of Port A. For each
bit to be affected by the successful OC1 compare, the corresponding bit in OC1M must be set to one.
Each Port A line associated with an OC1Mx bit which is set to one will be forced to be an output
regardless of the state of the associated DDRA bit. This does not change the state of the DDRA bit.
MOTOROLA
6-10
PROGRAMMABLE TIMER
MC68HC11G5
6.4.9
Output Compare 1 Action Data Register (OC1D)
$100D
7
OC1D7
6
OC1D6
5
OC1D5
4
OC1D4
3
OC1D3
2
0
1
0
0
0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time (bits 2 – 0 always return 0).
WRITE:
Any time (writes to bits 2 – 0 have no meaning or effect).
RESET:
$00
OC1D
OC1D is used to specify the data to be written to the affected bits of Port A as the result of
a successful OC1 compare. The bits of OC1D correspond bit-for-bit with the bits of Port A
(bits 3 – 7). When a successful OC1 compare occurs, for each bit that is set in OC1M, the
corresponding data bit in OC1D is written to the corresponding bit of Port A. If there is a
conflicting situation where an OC1 compare and another output compare function occur
during the same E-clock cycle, and both attempt to alter the same Port A bit, the OC1 action
will take priority.
One reason for providing this special capability on OC1 is to allow control of multiple I/O pins
automatically with a single output compare function. For example, if the OC2 and OC3 functions are
being used for internal timing functions, their associated Port A pins are free to be used for other
purposes. These two pins could be controlled simultaneously as high speed timed outputs using the
OC1 function by setting the two corresponding bits in the OC1M register to one.
The special I/O pin control on the OC1 function also allows more than one output compare function
to control a single I/O pin. For example, the OC1 function could be configured to affect only bit 3 of
Port A (by setting OC1M = $08). The OC5 function could set Port A bit 3 to a logic one and the OC1
function could reset it to a logic low on the very next count of the free-running counter.
6.4.10
Compare Force Register (CFORC)
7
FOC1
6
FOC2
5
FOC3
4
FOC4
3
FOC5
2
FOC6
1
FOC7
0
$100B
RESET:
0
0
0
0
0
0
0
0
READ:
Any time but will always return $00 (1 state is transient).
WRITE:
Any time (writes to bit 0 have no meaning or effect).
RESET:
$00 (no actions forced).
CFORC
FOC1 to FOC7 — Force Output Compare “x” Action
Writing a one to bit “x” in this register causes the action which is programmed for output
compare “x” to occur at the next transition of the prescaled timer clock. The action taken
is the same as if a successful comparison had just taken place with the TOCx register,
with the exception that the interrupt flag is not set.
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-11
6.4.11
Control Register 1 (TCTL1)
$1020
7
OM2
6
OL2
5
OM3
4
OL3
3
OM4
2
OL4
1
OM5
0
OL5
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00
TCTL1
OMx — Output Mode; OLx — Output Level
These four pairs of control bits are encoded to specify the output action to be taken as
a result of a successful OCx compare (OC2 – OC5). When either OMx or OLx is set, the
pin associated with OCx becomes an output tied to OCx regardless of the state of the
associated DDR bit. Output compare OC5 only functions if the TO5I4 register is
programmed for output compare OC5 operation via the I4/O5 bit in the PACTL register.
6.4.12
OMx
OLx
Action taken upon successful compare
0
0
Timer disconnected from output pin logic
0
1
Toggle OCx output line
1
0
Clear OCx output line to zero
1
1
Set OCx output line to one
Timer Control Register 2 (TCTL2)
$1021
7
EDG4B
RESET:
0
READ:
Any time
WRITE:
Any time
RESET:
$00
6
5
4
3
2
1
0
EDG4A EDG1B EDG1A EDG2B EDG2A EDG3B EDG3A
0
0
0
0
0
0
TCTL2
0
EDGxB, EDGxA — Input Capture Edge Control
The level transition which triggers counter transfer is defined by the corresponding
input edge bits (EDGxB, EDGxA). These bit pairs are encoded to configure input
captures IC1 – IC4 to occur on rising edges, falling edges, either edge, or to inhibit
capture. Input capture 4 only functions if the TO5I4 register is programmed for input
capture IC4 operation by the I4/O5 bit in the PACTL register.
MOTOROLA
6-12
PROGRAMMABLE TIMER
MC68HC11G5
Note:
6.4.13
EDGxB
EDGxA
Configuration
0
0
Capture disabled
0
1
Capture on rising edges only
1
0
Capture on falling edges only
1
1
Capture on any edge (rising or falling)
input captures do not force the direction of the associated port. If the port bit associated
with an input capture is programmed to be an output, then input captures will occur on
the appropriate changes of state caused by writing to the port.
Timer Control Register 3 (TCTL3)
$1050
7
EDG5B
RESET:
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00
6
5
4
EDG5A EDG6B EDG6A
0
0
0
3
OM6
2
OL6
1
OM7
0
OL7
0
0
0
0
TCTL3
EDGxB, EDGxA — Input Capture Edge Control
These control bits configure the input capture edge detector circuits for input captures
IC5 and IC6.
EDGxB
EDGxA
Configuration
0
0
Capture disabled
0
1
Capture on rising edges only
1
0
Capture on falling edges only
1
1
Capture on any edge (rising or falling)
Input capture IC5 only functions if the TO6I5 register is programmed for input capture IC5
operation by the I5/O6 bit in the TCTL4 register being set to one. Input capture IC6
functions only if the TO7I6 register is programmed for input capture IC5 operation by the
I6/O7 bit in the TCTL4 register being set to one.
OMx, OLx — Output Mode, Output Level
These control bits are encoded to specify the output action to be taken as a result of
successful compares on OC6 and OC7. When either OMx or OLx is set to one, the pin
associated with OCx becomes an output tied to OCx, regardless of the state of the
associated DDR bit.
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-13
OMx
OLx
Action taken upon successful compare
0
0
Timer disconnected from output pin logic
0
1
Toggle OCx output line
1
0
Clear OCx output line to zero
1
1
Set OCx output line to one
Output compare OC6 only functions if the TO6I5 register is programmed for output
compare OC6 operation by the I5/O6 bit in the TCTL4 register being set to zero. Output
compare OC7 functions only if the TO7I6 register is programmed for output compare
OC7 operation by the I6/O7 bit in the TCTL4 register being set to zero.
6.4.14
Control Register 4 (TCTL4)
$1051
7
CT2SP
6
CT1SP
5
0
4
0
3
0
2
0
1
I5/O6
0
I6/O7
RESET:
0
0
0
0
0
0
0
0
TCTL4
READ:
Any time (bits 2 – 7 always read 0 if not in test mode).
WRITE:
Any time (writes to bits 2 – 7 have no meaning or effect if not in test or
mode).
RESET:
$00
bootstrap
CT2SP — Timer Counter 2 Stop (used to facilitate testing)
0 – Timer counter 2 is free-running.
1 – Timer counter 2 is stopped if in test or bootstrap mode (SMOD = 1).
CT1SP — Timer Counter 1 Stop (used to facilitate testing)
0 – Timer counter 1 is free-running.
1 – Timer counter 1 is stopped if in test or bootstrap mode (SMOD = 1).
I5/O6 — Configure TO6I5 Register for Input Capture or Output Compare
0 – Output compare 6 function enabled (no IC5).
1 – Input capture 5 function enabled (no OC6).
I6/O7 — Configure TO7I6 Register for Input Capture or Output Compare
0 – Output compare 7 function enabled (no IC6).
1 – Input capture 6 function enabled (no OC7).
MOTOROLA
6-14
PROGRAMMABLE TIMER
MC68HC11G5
6.4.15
Main Timer Interrupt Mask Register 1 (TMSK1)
The bits in TMSK1 correspond bit-for-bit with the bits in the TFLG1 status register. A zero disables
the corresponding flag from causing a hardware interrupt. A one enables the corresponding flag to
cause a hardware interrupt.
$1022
7
OC1I
6
OC2I
5
OC3I
4
OC4I
3
4/5I
2
IC1I
1
IC2I
0
IC3I
RESET:
0
0
0
0
0
0
0
0
READ:
Any time
WRITE:
Any time
RESET
$00
TMSK1
OC1I, OC2I, OC3I, OC4I — Output Compare “x” Interrupt Enable
0 – Interrupt inhibited.
1 – OCx interrupt requested when OCxF flag set
4/5I — Input Capture 4/Output Compare 5 Interrupt Enable
0 – Interrupt inhibited.
1 – IC4 or OC5 interrupt requested when 4/5F flag set
IC1I, IC2I, IC3I — Input Capture “x” Interrupt Enable
0 – Interrupt inhibited.
1 – ICx interrupt requested when ICxF flag set
6.4.16
Main Timer Interrupt Flag Register 1 (TFLG1)
The main timer system flag register (TFLG1) contains flag bits which are set by hardware when the
corresponding timer interrupt condition occurs. Any flag bits in the TFLG1 register which are set will
remain set until they are cleared by writing ones to those bits.
$1023
7
OC1F
6
OC2F
5
OC3F
4
OC4F
3
4/5F
2
IC1F
1
IC2F
0
IC3F
RESET:
0
0
0
0
0
0
0
0
TFLG1
READ:
Any time.
WRITE:
Used in clearing mechanism (writing ones to bits set cause these bits to be
cleared).
RESET:
$00
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-15
OC1F, OC2F,OC3F, OC4F — Output Compare “x” Flag
Set when the 16-bit timer counter register matches the OCx compare register. These bits
are cleared by writing to the TFLG1 register with the corresponding bits (4–7) set.
4/5F — Input Capture 4/Output Compare 5 Flag
Set when an input capture occurs on IC4 or an output compare occurs on OC5. This bit
is cleared by writing to the TFLG1 register with bit 3 set.
IC1F, IC2F, IC3F — Input Capture “x” Flag
Set when an input capture occurs on ICx. These bits are cleared by writing to the TFLG1
register with the corresponding bits (0–2) set.
6.4.17
Miscellaneous Timer Interrupt Mask Register 2 (TMSK2)
The bits in TMSK2 correspond bit-for-bit with the bits in the TFLG2 status register. A zero inhibits
the corresponding flag from causing a hardware interrupt. A one enables the corresponding flag to
cause a hardware interrupt.
7
6
5
4
3
2
1
0
$1024
TO1I
RTII
PAOVI
PAII
TO2I
5/6I
6/7I
0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00
TMSK2
TO1I — Timer Overflow 1 Interrupt Enable
0 – Interrupt inhibited.
1 – Hardware interrupt requested when TO1F flag set.
RTII — RTI Interrupt Enable
0 – Interrupt inhibited.
1 – Hardware interrupt requested when RTIF flag set.
PAOVI — Pulse Accumulator Overflow Interrupt Enable
0 – Interrupt inhibited
1 – Hardware interrupt requested when PAOVF flag set
PAII — Pulse Accumulator Input Interrupt Enable
0 – Interrupt inhibited
1 – Hardware interrupt requested when PAIF flag set
MOTOROLA
6-16
PROGRAMMABLE TIMER
MC68HC11G5
TO2I — Timer Overflow 2 Interrupt Enable
0 – Interrupt inhibited
1 – Hardware interrupt requested when TO2F flag set
5/6I — Input Capture 5/Output Compare 6 Interrupt Enable
0 – Interrupt inhibited
1 – Hardware interrupt requested when 5/6F flag set
6/7I — Input Capture 6/Output Compare 7 Interrupt Enable
0 – Interrupt inhibited
1 – Hardware interrupt requested when 6/7F flag set
6.4.18
Miscellaneous Timer Interrupt Flag Register 2 (TFLG2)
The miscellaneous timer system flag register (TFLG2) contains flag bits which are set by hardware
when the corresponding timer interrupt condition occurs. Any flag bits in the TFLG1 register which
are set will remain set until they are cleared by writing ones to those bits.
$1025
7
TO1F
6
RTIF
5
PAOVF
4
PAIF
3
TO2F
2
5/6F
1
6/7F
0
0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Used in clearing mechanism (see above).
RESET:
$00
TFLG2
TO1F — Timer Overflow 1 Flag
Set when 16-bit free running timer 1 overflows from $FFFF to $0000. This bit is cleared
by writing to the TFLG2 register with bit 7 set.
RTIF — Real Time (Periodic) Interrupt Flag
Set when the tap point selected becomes set. This bit is cleared by writing to the
TFLG2 register with bit 6 set.
PAOVF — Pulse Accumulator Overflow Flag
Set when the 8-bit pulse accumulator overflows from $FF to $00. This bit is cleared
by writing to the TFLG2 register with bit 5 set.
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-17
PAIF — Pulse Accumulator Input Edge Flag
Set when the selected edge is detected at the PAI input pin. In event mode the event edge
triggers PAIF and in gated time accumulation mode the trailing edge of the gate signal
at the PAI input pin triggers PAIF. This bit is cleared by writing to the TFLG2 register with
bit 4 set.
TO2F — Timer Overflow 2 Flag
Set when 16-bit free-running timer 2 overflows from $FFFF to $0000. This bit is cleared
by writing to the TFLG2 register with bit 3 set.
5/6F — Input Capture 5/Output Compare 6 Flag
Set by input capture IC5 or output compare OC6, depending on which function is
selected. This bit is cleared by writing to the TFLG2 register with bit 2 set.
6/7F — Input Capture 6/Output Compare 7 Flag
Set by input capture IC6 or output compare OC7, depending on which function is
selected. This bit is cleared by writing to the TFLG2 register with bit 1 set.
6.4.19
Count Register (PACNT)
PACNT is a read/write 8-bit counter register which is not initialized by reset. The PACTL register
contains four control bits which enable and configure the pulse accumulator system. The pulse
accumulator uses Port A bit 7 as its PAI input but this pin can also serve as a general purpose I/O
pin and as the timer output compare OC1 output.
$1027
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
RESET:
U
U
U
U
U
U
U
U
READ:
Any time (returns count from pulse accumulator counter).
WRITE:
Any time.
RESET:
Indeterminate.
MOTOROLA
6-18
PROGRAMMABLE TIMER
PACNT
MC68HC11G5
6.4.20
Pulse Accumulator Control Register (PACTL)
$1026
7
0
6
PAEN
RESET:
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00
5
4
PAMOD PEDGE
0
3
I4/O5
2
RTR2
1
RTR1
0
RTR0
0
0
0
0
0
PACTL
PAEN — Pulse Accumulator System Enable
When PAEN is zero, the pulse accumulator counter is disabled from counting and the
PAIF and PAOVF flags cannot be set. The counter value and the states of the two flags
are not altered by the state of the PAEN bit (writing PAEN to zero does not clear them).
When PAEN is a one, the pulse accumulator counter and the setting mechanisms on the
two pulse accumulator flags PAIF and PAOVF are enabled.
0 – Pulse accumulator system disabled (no flags can become set and the counter is
stopped).
1 – Pulse accumulator system enabled
PAMOD — Pulse Accumulator Mode
The PAMOD control bit specifies “event” or “gated time accumulation” mode.
0 – Event counter mode.
1 – Gated time accumulation mode.
PEDGE — Pulse Accumulator Edge Control
The PEDGE bit is used to specify the active edge for the PAI input pin which is interpreted
as the trailing edge for the PAI gate enable input when the system is configured for gated
time accumulation.
PEDGE in Event Counter Mode (PAMOD = 0):
0 – Falling edges on PAI pin cause the count to be incremented.
1 – Rising edges on PAI pin cause the count to be incremented.
PEDGE in Gated Time Accumulation Mode (PAMOD = 1):
0 – PAI input pin high enables E divided by 64 clock to pulse accumulator and the
trailing falling edge on PAI sets the PAIF flag.
1 – PAI input pin low enables E divided by 64 clock to pulse accumulator and the
trailing rising edge on PAI sets the PAIF flag.
MC68HC11G5
PROGRAMMABLE TIMER
MOTOROLA
6-19
I4/O5 — Configure TO5I4 register for input capture or output compare
0 – Output compare 5 function enabled (no IC4).
1 – Input capture 4 function enabled (no OC5).
RTR2, RTR1, RTR0 — RTI Interrupt Rate
These bits select one of six rates for the real time periodic interrupt circuit (see
Table 6-1). Reset clears these bits and after reset a full RTI period elapses before
the first RTI interrupt occurs.
Table 6-1. Real Time Interrupt Rates
RTR2 RTR1 RTR0
Divide
E By
XTAL =
223
XTAL =
8.0MHz
XTAL =
4.9152MHz
XTAL =
4.0MHz
XTAL =
3.6864MHz
1
1
0
211
0.98 ms
1.02 ms
1.67 ms
2.05 ms
2.22 ms
1
1
1
212
1.95 ms
2.05 ms
3.33 ms
4.10 ms
4.44 ms
0
0
0
213
3.91 ms
4.10 ms
6.67 ms
8.19 ms
8.89 ms
0
0
1
214
7.81 ms
8.19 ms
13.33 ms
16.38 ms
17.78 ms
0
215
15.62 ms
16.38 ms
26.67 ms
32.77 ms
35.56 ms
1
216
31.25 ms
32.77 ms
53.33 ms
65.54 ms
71.11 ms
E=
2.1MHz
2.0MHz
1.2288MHz
1.0MHz
921.6kHz
0
0
1
1
MOTOROLA
6-20
PROGRAMMABLE TIMER
MC68HC11G5
SECTION 7
SERIAL COMMUNICATIONS INTERFACE
This section describes the UART type serial communications interface system (SCI). The SCI can
be used, for example, to connect a CRT terminal or personal computer to the MCU or to form a serial
communication network connecting several widely distributed MCUs. It should be noted that the SCI
is one of two independent serial I/O subsystems in the MC68HC11G5. The other serial I/O system
on the MC68HC11G5, the serial peripheral interface (SPI), provides for high speed synchronous
serial communication to peripherals or other MCUs (usually located on the same PC board as the
MC68HC11G5).
7.1
OVERVIEW AND FEATURES
The SCI on the MC68HC11G5 is a full duplex UART type asynchronous system. The SCI uses
standard non-return-to-zero (NRZ) format (one start bit, eight or nine data bits, and one stop bit).
An on-chip baud rate generator derives standard baud rate frequencies from the MCU oscillator.
Both the transmitter and the receiver are double buffered so back-to-back characters can be
handled easily, even if the CPU is delayed in responding to the completion of an individual character.
The SCI transmitter and receiver are functionally independent but use the same data format and
baud rate.
7.1.1
SCI Two-wire System Features:
•
Standard NRZ (mark/space) format.
•
Advanced error detection method includes noise detection for noise duration of up to 1/16th bit
time.
•
Full-duplex operation.
•
Software programmable for one of 32 different baud rates.
•
Software selectable word length (eight or nine bit words).
•
Separate transmitter and receiver enable bits.
•
Capable of being interrupt driven.
•
Four separate enable bits available for interrupt control.
7.1.2
SCI Receiver Features
•
Receiver wake-up function (idle line or address bit).
•
Idle line detect.
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-1
•
Framing error detect.
•
Noise detect.
•
Overrun detect.
•
Receiver data register full flag.
7.1.3
SCI Transmitter Features
•
Transmit data register empty flag.
•
Transmit complete flag.
•
Send break.
7.2
FUNCTIONAL DESCRIPTION
A block diagram of the SCI is shown in Figure 7-1. The user has option bits in serial control register
1 (SCCR1) to select the “wake-up” method (WAKE bit) and data word length (M bit) of the SCI. Serial
communications control register 2 (SCCR2) provides control bits which individually enable/disable
the transmitter or receiver (TE and RE, respectively), enable system interrupts (TIE, TCIE, ILIE) and
provide the wake-up enable bit (RWU) and the send break code bit (SBK). Control bits in the baud
rate register (BAUD) allow the user to select one of 32 different baud rates for the transmitter and
receiver.
Data transmission is initiated by a write to the serial communications data register (SCDR). Provided
the transmitter is enabled, data stored in the SCDR is transferred to the transmit data shift register.
This transfer of data sets the transmit data register empty flag (TDRE) in the SCI status register
(SCSR) and may generate an interrupt if the transmit interrupt is enabled. The transfer of data to
the transmit data shift register is synchronized with the bit rate clock (Figure 7-2). All data is
transmitted least significant bit first. Upon completion of data transmission, the transmission
complete flag (TC) in the SCSR is set (provided no pending data, preamble or break is to be sent),
and an interrupt may be generated if the transmit complete interrupt is enabled. If the transmitter
is disabled, and the data, preamble or break (in the transmit data shift register) has been sent, the
TC bit will also be set. This will also generate an interrupt if the transmission complete interrupt
enable bit (TCIE) is set. If the transmitter is disabled in the middle of a transmission, that character
will be completed before the transmitter gives up control of the TXD pin.
When SCDR is read, it contains the last data byte received, provided that the receiver is enabled.
The receive data register full flag bit (RDRF) in the SCSR is set to indicate that a data byte has been
transferred from the input serial shift register to the SCDR, which can cause an interrupt if the
receiver interrupt is enabled. The data transfer from the input serial shift register to the SCDR is
synchronized by the receiver bit rate clock. The OR (overrun), NF (noise), or FE (framing) error flags
in the SCSR may be set if data reception errors occurred.
An idle line interrupt is generated if the idle line interrupt is enabled and the IDLE bit (which detects
idle line transmission) in SCSR is set. This allows a receiver that is not in the wake-up mode to detect
the end of a message or the preamble of a new message, or to resychronize with the transmitter.
A valid character must be received before the idle line condition or the IDLE bit will not be set and
and idle line interrupt will not be generated.
MOTOROLA
7-2
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
Internal Bus
$102D
SCCR2
Transmit
Data Register
(See Note)
Receive Data
Register
(See Note)
TIE
TCIE
RIE
ILIE
TE
RE
SBK
RWU
Transmit Data
Shift Register
TXD
(PD1)
SCSR
$102E
FE
NF
OR
IDLE RDRF TC TDRE
$102F
$102F
SCI Interrupt
Receive Data
Shift Register
RXD
(PD0)
2
Wake-Up
Unit
SBK
TE
Transmit
Control
7
Flag
Control
Receive
Control
Internal
Processor
Clock
Rate Generator
$102B TCLR
0
$102C
T8
R8
SCP1 SCP0 RCKB SCR2 SCR1 SCR1 BAUD
0
M
WAKE
0
0
0
SCCR1
Figure 7-1. Serial Communications Interface Block Diagram
Note: The Serial Communications Data Register (SCDAT) is controlled by the internal R/W signal.
It is the transmit data register when written and the receive data register when read.
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-3
Oscillator
Frequency
+4
SCP0-SCP1
Prescaler
Control
+N
SCR0-SCR2
SCI Select
Rate Control
+M
SCI
Receive
Clock (RTI)
+ 16
SCI
Transmit
Clock (Tx)
Figure 7-2. Rate Generator Division
7.3
DATA FORMAT
Receive data or transmit data is the serial data that is transferred to the internal data bus from the
receive data input pin (RXD) or from the internal bus to the transmit data output pin (TXD). The nonreturn-to-zero (NRZ) data format shown in Figure 7-3 is used and must meet the following criteria:
1)
The idle line is brought to a logic one state prior to transmission/reception of a character.
2)
A start bit (logic zero) is used to indicate the start of a frame.
3)
The data is transmitted and received least significant bit first.
4)
A stop bit (logic one) is used to indicate the end of a frame. A frame consists of a start bit, a
character of eight or nine data bits, and a stop bit.
5)
A break is defined as the transmission or reception of a low (logic zero) for at least one complete
frame time.
Control Bit "M"
Selects
8 or 9 Bit Data
0
Idle Line
1
2
3
4
5
6
Start
7
8
0
Stop Start
Figure 7-3. Data Format
7.4
RECEIVER WAKE-UP OPERATION
The MC68HC11G5 receiver logic hardware also supports a receiver wake-up function which is
intended for systems having more than one receiver. With this function a transmitting device directs
messages to an individual receiver or group of receivers by passing addressing information as the
initial byte(s) of each message. The wake-up function allows receivers not addressed to remain in
in a dormant state for the remainder of the unwanted message. This eliminates any further software
overhead to service the remaining characters of the unwanted message and thus improves system
performance.
MOTOROLA
7-4
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
The receiver is placed in wake-up mode by setting the receiver wake-up bit (RWU) in the SCCR2
register. While RWU is set, all of the receiver related status flags (RDRF, IDLE, OR, NF, and FE)
are inhibited (cannot become set). Note that the idle line detect function is inhibited while the RWU
bit is set. Although RWU may be cleared by a software write to SCCR2, it would be unusual to do
so. Normally RWU is set by software and gets cleared automatically with hardware by one of the
two methods described below.
7.4.1
Idle Line Wake-up
In idle line wake-up mode, a dormant receiver wakes up as soon as the RXD line becomes idle. Idle
is defined as a continuous logic high level on the RXD line for ten (or eleven) full bit times. Systems
using this type of wake-up must provide at least one character time of idle between messages to
wake up sleeping receivers, but must not allow any idle time between characters within a message.
7.4.2
Address Mark Wake-up
In address mark wake-up, the most significant bit (MSB) in a character is used to indicate that the
character is an address (1) or a data (0) character. Sleeping receivers will wake up whenever an
address character is received. Systems using this method for wake-up would set the MSB of the first
character of each message and leave it clear for all other characters in the message. Idle periods
may be present within messages and no idle time is required between messages for this wake-up
method.
7.5
RECEIVE DATA (RXD)
Receive data is the serial data that is applied through the input line and the serial communications
interface to the internal bus. The receiver circuitry clocks the input at a rate equal to 16 times the
baud rate and this time is referred to as the RT clock.
Once a valid start bit is detected the start bit, each data bit and the stop bit are sampled three times
at RT intervals 8 RT, 9 RT and 10 RT (1 RT is the position where the bit is expected to start), as shown
in Figure 7-4. The value of the bit is determined by voting logic which takes the value of the majority
of the samples.
Previous Bit
RxD
16
R
T
Present Bit
1
R
T
Samples
v
v
v
8
9 10
R R R
T T T
Next Bit
16
R
T
1
R
T
Figure 7-4. Sampling Technique Used On All Bits
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-5
7.6
START BIT DETECTION
When the RXD input is detected low, it is tested for three more sample times (referred to as the start
edge verification samples in Figure 7-5). If at least two of these three verification samples detect a
logic zero, a valid start bit has been detected, otherwise the line is assumed to be idle. A noise flag
is set if all three verification samples do not detect a logic zero. A valid start bit could be assumed
with a set noise flag present.
If there has been a framing error without detection of a break (10 zeros for 8-bit format or 11 zeros
for 9-bit format), the circuit continues to operate as if there actually was a stop bit and the start edge
will be placed artificially. The last bit received in the data shift register is inverted to a logic one, and
the three logic one start qualifiers (shown in Figure 7-5) are forced into the sample shift register
during the interval when detection of a start bit is anticipated (see Figure 7-6); therefore, the start
bit will be accepted no sooner than it is anticipated.
If the receiver detects that a break produced the framing error, the start bit will not be artificially
induced and the receiver must actually detect a logic one before the start bit can be recognised (see
Figure 7-7).
16X Internal Sampling Clock
RT Clock Edges (For all three Examples)
1
R
T
2
R
T
3
R
T
4
R
T
5
R
T
6
R
T
7
R
T
8
R
T
Idle
Start
RXD
1
1
1
1
1
1
1
1
1
1
Start
Qualifiers
0
0
Idle
0
0
Start Edge
Verification Samples
Noise
Start
RXD
1
1
1
1
Idle
1
1
1
1
1
1
0
0
1
0
0
0
0
Noise
Start
RXD
1
1
1
1
0
1
1
1
1
1
0
Figure 7-5. Examples of Start Bit Sampling Techniques
MOTOROLA
7-6
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
Data
Expected Stop
Artifical Edge
Receive
Data In
Start Bit
Data
Data
Samples
(a) Case 1, Receive Line Low During Artificial Edge
Data
Expected Stop
Start Edge
Receive
Data In
Start Bit
Data
Data
Samples
(b) Case 2, Receive Line High During Expected Start Edge
Figure 7-6. SCI Artificial Start Following a Framing Error
Expected Stop
Break
Detected as Valid
Start Edge
Receive
Data In
Start Bit
Data Samples
Start
Start Edge
Qualifiers Verification
Samples
Figure 7-7. SCI Start Bit Following a Break
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-7
7.7
TRANSMIT DATA (TXD)
Transmit data is the serial data from the internal data bus that is applied through the serial
communications interface to the output line. The transmitter generates a bit time by using a
derivative of the RT clock, thus producing a transmission rate equal to 1/16th that of the receiver
sample clock.
7.8
SCI REGISTERS
Primarily the SCI system is configured and controlled by five registers BAUD, SCCR1, SCCR2,
SCSR, and SCDAT). In addition, the Port D data and data direction registers and the Port D wiredOR mode bit in the SPCR register are secondarily related to the SCI system. Reference should be
made to the block diagram shown in Figure 7-1.
7.8.1
Serial Communications Data Register (SCDAT)
The SCI data register (SCDAT) shown in the following figure is actually two separate registers.
When SCDAT is read, the read-only receive data register is accessed and when SCDAT is written,
the write-only transmit data register is accessed.
$102F
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
RESET:
0
0
0
0
0
0
0
0
READ:
Accesses the read-only SCI receive data register (RDR).
WRITE:
Accesses the write-only SCI transmit data register (TDR).
RESET:
Does not affect this address.
7.8.2
SCDAT
Serial Communications Control Register 1 (SCCR1)
The SCI control register 1 (SCCR1) contains control bits related to the nine data bit character format
and the receiver wake-up feature. Four of the bits in this register are not used and always read as
zeros.
$102C
7
R8
6
T8
5
0
4
M
3
WAKE
2
0
1
0
0
0
RESET:
U
U
0
0
0
0
0
0
MOTOROLA
7-8
SERIAL COMMUNICATIONS INTERFACE
SCCR1
MC68HC11G5
R8 — Receive Data Bit 8
READ:
Any time.
WRITE:
Has no meaning or effect.
This bit is the ninth serial data bit received when the SCI system is configured for nine
data bit operation (M = 1). The most significant bit (bit 8) of the received character is
transferred into this bit at the same time as the remaining eight bits (bits 0 – 7) are
transferred from the serial receive shifter to the SCI receive data register.
T8 — Transmit Data Bit 8
READ:
Any time.
WRITE:
Any time.
This bit is the ninth data bit to be transmitted when the SCI system is configured for nine
data bit operation (M = 1). When the eight low order bits (bits 0 – 7) of a transmit character
are transferred from the SCI data register to the serial transmit shift register, this bit (bit 8)
is transferred to the ninth bit position of the shifter.
M — Mode (select character format)
READ:
Any time.
WRITE:
Any time.
0 – 1 start bit, 8 data bits, 1 stop bit.
1 – 1 start bit, 8 data, 9th data bit, 1 stop bit.
The M bit controls the character length for both the transmitter and receiver at the same
time. The 9th data bit is most commonly used as an extra stop bit or in conjunction with
the “address mark” wake-up method. It can also be used as a parity bit.
WAKE — Wake-up Mode Select
READ:
Any time.
WRITE:
Any time.
0 – Wake-up on idle line.
1 – Wake-up on address mark.
Note:
7.8.3
Bits 2 – 1 are not implemented and always read as zeros.
Serial Communications Control Register 2 (SCCR2)
The SCI control register 2 (SCCR2) provides the control bits that enable/disable individual SCI
functions.
$102D
7
TIE
6
TCIE
5
RIE
4
ILIE
3
TE
2
RE
1
RWU
0
SBK
RESET:
0
0
0
0
0
0
0
0
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
SCCR2
MOTOROLA
7-9
READ:
Any time
WRITE:
Any time
RESET:
$00
TIE — Transmit Interrupt Enable
0 – TDRE interrupts disabled
1 – SCI interrupt if TDRE = 1
TCIE — Transmit Complete Interrupt Enable
0 – TC interrupts disabled
1 – SCI interrupt if TC = 1
RIE — Receiver Interrupt Enable
0 – RDRF and OR interrupts disabled
1 – SCI interrupt if RDRF or OR = 1
ILIE — Idle Line Interrupt Enable
0 – IDLE interrupts disabled.
1 – SCI interrupt if IDLE = 1
TE — Transmitter Enable
When the transmit enable bit is set, the transmit shift register output is applied to the TXD
line. Depending on the state of control bit M (SCCR1), a preamble of 10 (M = 0) or 11 (M
= 1) consecutive ones is transmitted when software sets the TE bit from a cleared state.
After loading the last byte in the serial communications data register and receiving the
TDRE flag, the user can clear TE. Transmission of the last byte will then be completed
before the transmitter gives up control of the TXD pin. While the transmitter is active, the
data direction register control for Port D bit 1 is overridden and the line is forced to be an
output.
RE — Receiver Enable
When the receiver enable bit is set, the receiver is enabled. When RE is clear, the receiver
is disabled and all of the status bits associated with the receiver (RDRF, IDLE, OR, NF
and FE) are inhibited. While the receiver is enabled, the data direction register control
for Port D bit 0 is overridden and the line is forced to be an input.
RWU — Receiver Wake-up
When the receiver wake-up bit is set by the user software, it puts the receiver to sleep
and enables the wake-up function. If the WAKE bit is cleared, RWU is cleared by the SCI
logic after receiving 10 (M = 0) or 11 (M = 1) consecutive ones. If the WAKE bit is set, RWU
is cleared by the SCI logic after receiving a data word whose MSB is set.
SBK — Send Break
If the send break bit is toggled set and cleared, the transmitter sends 10 (M = 0) or 11 (M
= 1) zeros and then reverts to idle sending data. If SBK remains set, the transmitter will
continually send whole blocks of zeros (sets of 10 or 11) until cleared. At the completion
MOTOROLA
7-10
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
of the break code, the transmitter sends at least one high bit to guarantee recognition of
a valid start bit. If the transmitter is currently empty and idle, setting and clearing SBK is
likely to queue two character times of break because the first break transfers almost
immediately to the shift register and the second is then queued into the parallel transmit
buffer.
7.8.4
Serial Communications Status Register (SCSR)
The serial communications status register (SCSR) provides inputs to the interrupt logic circuits for
generation of the SCI system interrupt.
$102E
7
TDRE
6
TC
5
RDRF
4
IDLE
3
OR
2
NF
1
FE
0
0
RESET:
1
1
0
0
0
0
0
0
READ:
Any time (used in auto clearing mechanism).
WRITE:
Has no meaning or effect.
SCSR
TDRE — Transmit Data Register Empty Flag
This bit is set when the byte in the transmit data register is transferred to the serial shift
register. New data will not be transmitted unless the SCSR register is read before writing
to the transmit data register. Reset sets this bit.
TC — Transmit Complete Flag
This bit is set to indicate that the SCI transmitter has no meaningful information to transmit
(no data in shifter, no preamble, no break). When TC is set the serial line will go idle
(continuous MARK). Reset sets this bit.
RDRF — Receive Data Register Full Flag
This bit is set when the contents of the receiver serial shift register is transferred to the
receiver data register.
IDLE — Idle Line Detected Flag
This bit is set when a receiver idle line is detected (the receipt of a minimum of ten/eleven
consecutive “1”s). This bit will not be set by the idle line condition when the RWU bit is
set. Once cleared, IDLE will not be set again until after RDRF has been set, (until after
the line has been active and becomes idle again).
OR — Overrun Error Flag
This bit is set when a new byte is ready to be transferred from the receiver shift register
to the receiver data register and the receive data register is already full (RDRF bit is set).
Data transfer is inhibited until this bit is cleared.
MC68HC11G5
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-11
NF — Noise Error Flag
This bit is set if there is noise on a “valid” start bit, any of the data bits, or on the stop bit.
The NF bit is set during the same cycle as the RDRF bit but does not get set in the case
of an overrun (OR).
FE — Framing Error Flag
This bit is set when the word boundaries in the bit stream are not synchronized with the
receiver bit counter (generated by the reception of a logic zero bit where a stop bit was
expected). The FE bit reflects the status of the byte in the receive data register and the
transfer from the receive shifter to the receive data register is inhibited in the case of
overrun. The FE bit is set during the same cycle as the RDRF bit but does not get set in
the case of an overrun (OR). The framing error flag inhibits further transfer of data into
the receive data register until it is cleared.
7.8.5
Baud Rate Register (BAUD)
The baud rate register (BAUD) is used to set the bit rate for the SCI system. Normally this register
is written once, during initialization, to set the baud rate for SCI communications. Both the receiver
and the transmitter use the same baud rate which is derived from the MCU bus rate clock. A two
stage divider is used to develop custom baud rates from normal MCU crystal frequencies so it is not
necessary to use special baud rate crystal frequencies.
$102B
7
TCLR
6
0
5
SCP1
4
SCP0
3
RCKB
2
SCR2
1
SCR1
0
SCR0
RESET:
0
0
0
0
0
U
U
U
BAUD
TCLR — Clear Baud Rate Counters (for test purposes only)
READ:
Always returns 0.
WRITE:
Only while SMOD = 1 (test or bootstrap mode)
This bit is disabled and remains low in any mode other than test or bootstrap mode. Reset
clears this bit. While in test or bootstrap mode, setting this bit causes the baud rate
counter chains to be reset. The logic one state of this bit is transitory and reads always
return a logic zero. This control bit is intended only for factory testing of the MCU.
SCP1, SCP0 — Serial Prescaler Select bits
READ:
Any time
WRITE:
Any time
The E-clock is divided by the factors shown in Table 7-1. This prescaled output provides
an input to a divider which is controlled by the SCI rate select bits (SCR2 – SCR0).
MOTOROLA
7-12
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
Table 7-1. First Prescaler Stage
SCP1
SCP0
Internal Processor
Clock Divide By
0
0
1
0
1
3
1
0
4
1
1
13
SCR2, SCR1, SCR0 — SCI Rate Select bits
READ:
Any time
WRITE:
Any time
These three bits select the baud rates for both the transmitter and the receiver. The
prescaler output described above is divided by the factors shown in Table 7-2.
Table 7-2. Second Prescaler Stage
MC68HC11G5
SCR2
SCR1
SCR0
Prescaler Output
Divide By
0
0
0
1
0
0
1
2
0
1
0
4
0
1
1
8
1
0
0
16
1
0
1
32
1
1
0
64
1
1
1
128
SERIAL COMMUNICATIONS INTERFACE
MOTOROLA
7-13
RCKB — SCI Receive Baud Rate Clock Test
READ:
Always returns logic 0
WRITE:
Only while SMOD = 1 (test or bootstrap mode)
This bit is disabled and remains low in any mode other than test or bootstrap modes.
Reset clears this bit. While in test or bootstrap mode, this bit may be written but not read
(reads always return a logic zero). Setting this bit enables a baud rate counter test mode
where the exclusive-or of the receiver clock (16 times the baud rate) and the transmit
clock (1 times the baud rate) is driven out the PD1/TXD pin. This control bit is intended
only for factory testing of the MCU.
MOTOROLA
7-14
SERIAL COMMUNICATIONS INTERFACE
MC68HC11G5
SECTION 8
SERIAL PERIPHERAL INTERFACE
This section contains a description of the serial peripheral interface (SPI).
8.1
OVERVIEW AND FEATURES
The SPI is a synchronous interface which allows several SPI microcontrollers or SPI-type
peripherals to be interconnected. In a serial peripheral interface, separate wires (signals) are
required for data and clock. In the SPI format, the clock is not included in the data stream and must
be furnished as a separate signal. The MC68HC11G5 SPI system may be configured either as a
master or as a slave.
Features include:
•
Full-duplex, 3-wire synchronous transfers
•
Master or slave operation
•
1.05 MHz (maximum) master bit frequency
•
2.1 MHz (maximum) slave bit frequency
•
Four programmable master bit rates
•
Programmable clock polarity and phase
•
End-of-transmission interrupt flag
•
Write collision flag protection
•
Master-master mode fault protection
•
Easy interface to simple expansion parts (PLLs, D/As, latches, display drivers, etc.)
8.2
SPI SIGNAL DESCRIPTIONS
The SPI interface consists of four Port D lines (MISO, MOSI, SCK, and SS). These signals are
discussed in the following paragraphs for both master mode and slave mode of operation.
Any SPI output line has to have its corresponding data direction register bit set. If this bit is clear,
the line is disconnected from the SPI logic and becomes a general-purpose input line. Any SPI
input line is forced to act as an input regardless of the state of the corresponding data direction
register bit.
MC68HC11G5
SERIAL PERIPHERAL INTERFACE
MOTOROLA
8-1
8.2.1
Master In Slave Out (MISO)
The MISO line is configured as an input in a master device and as an output in a slave device. It is
one of the two lines that transfer serial data in one direction, with the most significant bit sent first.
The MISO line of a slave device is placed in the high-impedance state if the slave is not selected.
8.2.2
Master Out Slave In (MOSI)
The MOSI line is configured as an output in a master device and as an input in a slave device. It is
one of the two lines that transfer serial data in one direction with the most significant bit sent first.
8.2.3
Serial Clock (SCK)
The serial clock is used to synchronize data movement both in and out of the device through its MOSI
and MISO lines. The master and slave devices are capable of exchanging a byte of information
during a sequence of eight clock cycles. Since SCK is generated by the master device, this line
becomes an input on a slave device.
SS
SS
SCK
(CPOL = 0, CPHA = 0)
SCK
(CPOL = 0, CPHA = 1)
SCK
(CPOL = 1, CPHA = 0)
SCK
(CPOL = 1, CPHA = 1)
MISO/MOSI
MSB
6
5
4
3
2
1
LSB
Internal Strobe for Data Capture (All Modes)
Figure 8-1. Data Clock Timing Diagram
MOTOROLA
8-2
SERIAL PERIPHERAL INTERFACE
MC68HC11G5
As shown in Figure 8-1, four different timing relationships may be selected by control bits CPOL and
CPHA in the serial peripheral control register (SPCR). Both master and slave devices must operate
with the same timing. The master device always places data on the MOSI line a half cycle before
the clock edge (SCK), in order for the slave device to latch the data.
Two bits (SPR0 and SPR1) in the SPCR of the master device select the clock rate. In a slave device,
SPR0 and SPR1 have no effect on the operation of the SPI.
8.2.4
Slave Select (SS)
The slave select (SS) input line is used to select a slave device. It must be in the active low state
prior to data transactions and must stay low for the duration of the transaction.
The SS line on the master must be tied high. If it goes low, a mode fault error flag (MODF) is set in
the serial peripheral status register (SPSR). The SS pin can be selected to be a general-purpose
output by writing a one in bit 5 of the Port D data direction register, thus disabling the mode fault
circuit. The other three SPI lines are dedicated to the SPI whenever the SPI is on.
When CPHA = 0, the shift clock is the logical OR of SS and SCK. In this clock phase mode, SS must
go high between successive characters in an SPI message. When CPHA = 1, SS may be left low
for several SPI characters. If there is only one SPI slave MCU, its SS line may be tied to VSS provided
CPHA = 1 clock modes are used.
Figure 8-2 shows a block diagram of the serial peripheral interface circuitry. When a master device
transmits data to a slave device via the MOSI line, the slave device responds by sending data to the
master device via the master’s MISO line. This implies full duplex transmission with both data out
and data in synchronized to the same clock signal. Thus, the byte transmitted is replaced by the byte
received and eliminates the need for separate transmitter-empty and receiver-full status bits. A
single status bit (SPIF) is used to signify that the I/O operation has been completed.
The SPI is double buffered on read, but not on write. If a write is performed during data transfer, the
transfer is not interrupted, and the write will be unsuccessful. This condition will cause the write
collision status bit (WCOL) in the SPSR to be set. After a data byte is shifted, the SPIF flag in the
SPSR is set.
In master mode, the SCK pin is an output. It idles high or low, depending on the SPOL bit in the
SPCR, until data is written to the shift register, at which point eight clocks are generated to shift the
eight bits of data, after which SCK goes idle again.
In slave mode, the slave start logic receives a logic low on the SS pin and a clock input at the SCK
pin. Thus, the slave is synchronized to the master. Data from the master is received serially via the
slave MOSI line and is loaded into the 8-bit shift register. The data is then transferred, in parallel,
from the 8-bit shift register to the read buffer. During a write cycle, data is written into the shift register,
then the slave waits for a clock train from the master to shift the data out on the slave’s MISO line.
Figure 8-3 illustrates the MOSI, MISO and SS master-slave interconnections.
MC68HC11G5
SERIAL PERIPHERAL INTERFACE
MOTOROLA
8-3
FUNCTIONAL DESCRIPTION
Internal
MCU Clock
MSB
Divider
÷2 ÷4 ÷16 ÷32
LSB
8-bit Shift Register
S
M
MISO
PD2
S
M
MOSI
PD3
Read Data Buffer
Clock
SPI Clock (Master)
Select
S
M
SPR1
SPR0
Clock
Logic
Pin Control Logic
8.3
MSTR
SPE
DWOM
SS
PD5
MSTR
SPE
MODF
SPIE
SPE
DWOM
MSTR
CPHA
CPOL
SPR1
SPR0
SPI Control
SPIF
WCOL
SCK
PD4
SPI Status Register
SPI Interrupt
Request
SPI Control Register
Internal
Data Bus
Figure 8-2. Serial Peripheral Interface Block Diagram
MOTOROLA
8-4
SERIAL PERIPHERAL INTERFACE
MC68HC11G5
Master
Slave
8-bit Shift Register
MISO
MISO
MOSI
MOSI
SCK
SPI Clock Generator
SS
8-bit Shift Register
SCK
+5V SS
Figure 8-3. Serial Peripheral Interface Master-Slave Interconnection
Due to data direction register control of SPI outputs and the Port D wire-OR mode (DWOM) option,
the SPI system can be configured in a variety of ways. Systems with a single bidirectional data path
rather than separate MISO and MOSI paths can be accommodated. Since MC68HC11G5 slaves
can selectively disable their MISO output, a broadcast message protocol is also possible.
8.4
SPI REGISTERS
There are three registers in the serial peripheral interface which provide control, status and data
storage functions. These registers are called the serial peripheral control register (SPCR), the serial
peripheral status register (SPSR) and the serial peripheral data I/O register (SPDAT).
8.4.1
Control Register (SPCR)
7
6
5
4
3
2
1
0
$1028
SPIE
SPE
DWOM
MSTR
CPOL
CPHA
SPR1
SPR0
RESET:
0
0
0
0
0
1
U
U
READ:
Any time
WRITE:
Any time.
SPCR
SPIE — SPI Interrupt Enable
0 – SPI interrupts disabled.
1 – SPI interrupts enabled.
When this bit is set to one, a hardware interrupt sequence is requested each time the
SPIF or MODF status flag is set. SPI interrupts are inhibited if this bit is clear or if the I
bit in the CC Register is set.
SPE — SPI System Enable
0 – SPI system off.
1 – SPI system on.
MC68HC11G5
SERIAL PERIPHERAL INTERFACE
MOTOROLA
8-5
When the SPE bit is set the Port D bit 2, 3, 4, and 5 pins are dedicated to the SPI function.
If the SPI is in master mode and DDRD bit 5 is set, then the Port D bit 5 pin becomes a
general purpose output instead of the SS input.
DWOM — Port D Wired-OR Mode
0 – Port D output buffers operate normally (CMOS outputs).
1 – Port D output buffers operate as open-drain outputs.
DWOM affects all six Port D pins together.
MSTR — Master/Slave Mode Select
0 – Slave mode.
1 – Master mode.
CPOL — Clock Polarity
When the clock polarity bit is cleared and data is not being transferred, a steady state low
value is produced at the SCK pin of the master device. Conversely, if this bit is set,
the SCK pin will idle high. This bit is also used in conjunction with the clock phase
control bit to produce the desired clock-data relationship between master and slave. See
Figure 8-1.
CPHA — Clock Phase
The clock phase bit, in conjunction with the CPOL bit, controls the clock-data relationship
between master and slave. The CPOL bit can be thought of simply as inserting an inverter
in series with the SCK line. The CPHA bit selects one of two fundamentally different
clocking protocols. When CPHA = 0, the shift clock is the logical OR of SCK and SS. As
soon as SS goes low, the transaction begins and the first edge on SCK invokes the first
data sample. When CPHA = 1, the SS pin may be thought of as a simple output enable
control. Refer to Figure 8-1.
SPR1, SPR0 — SPI Clock (SCK) Rate Select Bits
If the device is a master, the two serial peripheral rate bits select one of four division ratios
of the E-clock to be used as SCK (see Table 8-1). These bits have no effect in slave mode.
Table 8-1. SPI Rate Selection
MOTOROLA
8-6
SPR1
SPR0
Internal Processor
Clock Divide By
0
0
2
0
1
4
1
0
16
1
1
32
SERIAL PERIPHERAL INTERFACE
MC68HC11G5
8.4.2
Status Register (SPSR)
$1029
7
SPIF
6
WCOL
5
0
4
MODF
3
0
2
0
1
0
0
0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Has no meaning or effect.
SPSR
SPIF — SPI Interrupt Request Flag
The serial peripheral data transfer flag bit is set after the eighth SCK cycle in a data
transfer and it is cleared by reading the SPSR register (with SPIF set) followed by reading
from or writing to the SPI Data Register (SPDAT).
WCOL — Write Collision
The write collision bit is used to indicate that a serial transfer was in progress when the
MCU tried to write new data into the SPDAT data register. The MCU write is disabled to
avoid writing over the data being transmitted. No interrupt is generated because the error
status flag can be read upon completion of the transfer that was in progress at the time
of the error. This flag is automatically cleared by a read of the SPSR (with WCOL set)
followed by an access (read or write) to the SPDAT register.
MODF — SPI Mode Error Interrupt Status Flag
This bit is set automatically by SPI hardware if the MSTR control bit is set to one and the
SS input pin goes low. This condition is not permitted in normal operation. In the special
case where DDRD bit 5 is set to one, the Port D bit 5 pin is a general purpose output pin
rather than being dedicated as the slave select input for the SPI system. In this special
case the mode error function is inhibited and MODF remains at zero. This flag is
automatically cleared by a read of the SPSR (with MODF set) followed by a write to the
SPCR register.
8.4.3
Data I/O Register (SPDAT)
$102A
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time (normally only after SPIF flag set)
WRITE:
Any time (see WCOL write collision flag).
RESET:
Does not affect this register.
SPDAT
The serial peripheral data I/O register is used to transmit and receive data on the serial bus. Only
a write to this register will initiate transmission/reception of another byte, and this will only occur in
MC68HC11G5
SERIAL PERIPHERAL INTERFACE
MOTOROLA
8-7
the master device. At the completion or transmitting a byte of data, the SPIF status bit is set in both
the master and slave devices.
When the user reads the serial peripheral data I/O register, a buffer is actually being read. The first
SPIF must be cleared by the time a second transfer of data from the shift register to the read buffer
is initiated or an overrun condition will exist. In cases of overrun, the byte which causes the overrun
is lost.
A write to the serial peripheral data I/O register is not buffered and places data directly into the shift
register for transmission.
MOTOROLA
8-8
SERIAL PERIPHERAL INTERFACE
MC68HC11G5
SECTION 9
ANALOG-TO-DIGITAL CONVERTER
The Analog to Digital converter system consists of a single 10-bit successive approximation type
converter and a 16-channel multiplexer. Eight of the channels are connected to pins on the
MC68HC11G5, four are unused and the remaining four channels are dedicated to internal reference
points or test functions. There are eight 10-bit result registers and control logic allows for four or eight
consecutive conversions before stopping or for conversions to continue with the newest conversion
overwriting the oldest result register. Also, the control logic allows conversions to be performed on
a single selected channel, multiple times or consecutively on a selected group of four channels. In
addition, the control logic allows for converting all eight channels and either stopping or converting
continuously.
Two dedicated lines (Vrl and Vrh) are provided for the reference voltage inputs. These pins may be
connected to a separate or isolated power supply to ensure full accuracy of the AD conversion.
The 10-bit A/D converter accepts analog inputs ranging from Vrl to Vrh. Smaller input ranges can
also be obtained by adjusting Vrl and Vrh to the desired upper and lower limits. Conversion is
specified and tested for Vrl = 0 volts and Vrh = 5 volts. The A/D system can be operated with Vrh below
VDD and/or Vrl above VSS as long as Vrh is above Vrl by enough to support the conversions (2.5
to 5.0 volts).
Each set of four conversions takes 144 cycles of the E-clock, provided that E is greater than or equal
to 750 kHz. If E is less than 750 kHz, an internal R-C oscillator, which is nominally 1.5 MHz, must
be used for the A/D conversion clock. When the internal R-C oscillator is being used as the
conversion clock, the conversion complete flag (CCF) must be used to determine when a conversion
sequence has been completed. When using the internal R-C oscillator for A/D conversions the
sample and conversion process runs at the nominal 1.5 MHz rate; however, the conversion results
must be transferred to the MCU result registers synchronously with the MCU E-clock, so conversion
time is limited to a maximum of one channel per E-clock cycle.
Two control bits in the OPTION register control the basic configuration of the A/D system. The A to D
power-up bit (ADPU) allows the system to be disabled, resulting in reduced power consumption
when the A/D system is not being used. Any conversion which is in process when ADPU is written
to zero will be aborted. A delay of typically 100 microseconds is required after turning on the A/D
(by writing ADPU from 0 to 1) for the analog and comparator sections to stabilize. The CSEL bit is
used to select either the internal R-C oscillator or the MCU E-clock as the A/D system clock source.
MC68HC11G5
ANALOG-TO-DIGITAL CONVERTER
MOTOROLA
9-1
9.1
CONVERSION PROCESS
The A/D converter is ratiometric. An input voltage equal to Vrh converts to $FFC0 (full scale) and
an input voltage equal to Vrl converts to $0000. An input voltage greater than Vrh will convert to
$FFC0 with no overflow indication. Note that the six least significant bits always read zero. For
ratiometric conversions, the source of each analog input should use Vrh as the supply voltage and
be referenced to Vrl.
The A/D reference inputs are applied to a precision internal digital-to-analog converter. Control logic
drives this D/A and the analog output is successively compared to the selected analog input which
was sampled at the beginning of the conversion time. The conversion process is monotonic with no
missing codes.
9.2
CHANNEL ASSIGNMENTS
A multiplexer allows the single A/D converter to select one of sixteen analog signals. Eight of these
channels are supported on the Port E input pins. Of the eight other channels, four are reserved for
future use and four are for internal reference points and testing purposes. Table 9-1 shows the
signals selected by the channel select bits (CD, CC, CB, CA) in the ADCTL register. All “reserved”
channels are connected to Vrl.
Table 9-1. Channel Assignments
CONV8 = 0
Result in register if
CD
CC
CB
CA
Channel Signal
MULT = 1
MULT = 0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
AN1 (PE0)
AN2 (PE1)
AN3 (PE2)
AN4 (PE3)
ADR5
ADR6
ADR7
ADR8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
AN5 (PE4)
AN6 (PE5)
AN7 (PE6)
AN8 (PE7)
ADR5
ADR6
ADR7
ADR8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
1
0
X
X
reserved
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
1
Vrh
Vrl
Vrh/2
ADR5
ADR6
ADR7
ADR8
ADR5 – 8
ADR5 – 8
ADR5 – 8
ADR5 – 8
MOTOROLA
9-2
Test (reserved)
ANALOG-TO-DIGITAL CONVERTER
MC68HC11G5
Table 9-1. Channel Assignments (continued)
CONV8 = 1
9.3
Result in register if
CD
CC
CB
CA
Channel Signal
MULT = 1
MULT = 0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
AN1 (PE0)
AN2 (PE1)
AN3 (PE2)
AN4 (PE3)
ADR1
ADR2
ADR3
ADR4
ADR1 – 8
ADR1 – 8
ADR1 – 8
ADR1 – 8
0
0
0
0
1
1
1
1
0
0
1
1
0
1
0
1
AN5 (PE4)
AN6 (PE5)
AN7 (PE6)
AN8 (PE7)
ADR5
ADR6
ADR7
ADR8
ADR1 – 8
ADR1 – 8
ADR1 – 8
ADR1 – 8
1
0
X
X
reserved
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
1
Vrh
Vrl
Vrh /2
Test (reserved)
ADR5
ADR6
ADR7
ADR8
ADR1 – 8
ADR1 – 8
ADR1 – 8
ADR1 – 8
SINGLE CHANNEL OPERATION
Single channel operation is selected by writing a zero to the MULT bit in the A/D control and status
register (ADCTL). This mode has four variations, which can be selected using the CONV8 and
SCAN bits in the ADCTL register. In the first two variations, the CONV8 bit is clear and the single
selected channel is converted four consecutive times. In the second two variations, the CONV8 bit
is set and the single selected channel is converted eight consecutive times. The state of the SCAN
bit determines whether continuous or single scanning is selected. The channel is selected by the
CD – CA bits in the ADCTL register.
9.3.1
4-Conversion, Single Scan
Whichever Port E bit is selected, the first result will be stored in the ADR5 result register and
the fourth result will be stored in the ADR8 register. After the fourth conversion is complete
all conversion activity is halted until a new conversion command is written to the ADCTL
control register.
9.3.2
4-Conversion, Continuous Scan
Conversions continue to be performed on the selected channel with the fifth conversion being stored
in the ADR5 register (overwriting the first conversion result), the sixth conversion overwrites ADR6,
the seventh overwrites ADR7, and so on continuously. Using this variation, the data in any result
register is at most four conversion times old.
MC68HC11G5
ANALOG-TO-DIGITAL CONVERTER
MOTOROLA
9-3
9.3.3
8-Conversion, Single Scan
The result of the first conversion will be placed in result register ADR1, while the result of the
eighth conversion will be placed in result register ADR8. After the eighth conversion is complete all
conversion activity is halted until a new conversion command is written to the ADCTL control register.
9.3.4
8-Conversion, Continuous Scan
Conversions continue to be performed on the selected channel with the ninth conversion being
stored in the ADR1 register (overwriting the first conversion result), the tenth conversion overwrites
ADR2, the eleventh overwrites ADR3, and so on continuously. Using this variation, the data in any
result register is at most eight conversion times old.
9.4
MULTIPLE CHANNEL OPERATION
Multiple channel operation is selected by writing a one to the MULT bit in the A/D control and status
register (ADCTL). This mode has four variations, which can be selected using the CONV8 and
SCAN bits in the ADCTL register In the first two variations, the CONV8 bit is clear; and either Port
E bits 0 – 3 or Port E bits 4 – 7 are selected. (In this multiple channel mode, only the two most
significant bits of the channel address (CD and CC) are decoded.) In the second two variations, the
CONV8 bit is set and all eight channels are converted. The state of the SCAN bit determines whether
continuous or single scanning is selected.
9.4.1
4-Channel Single Scan
Either Port E bits 0 – 3 are selected or Port E bits 4 – 7 are selected. The first result is stored in the
ADR5 result register and the fourth result is stored in the ADR8 register. After the fourth conversion
is complete, all conversion activity is halted until a new conversion command is written to the ADCTL
control register.
9.4.2
4-Channel Continuous Scan
Conversions continue to be performed on the selected group of channels with the fifth conversion
being stored in the ADR5 register (replacing the earlier conversion result for the first channel in the
group), the sixth conversion overwrites ADR6, the seventh overwrites ADR7, and so on, continuously.
Using this second variation the data in any result register is, at most, four conversion times old.
9.4.3
8-Channel Single Scan
When CONV8 is set and MULT is set, all eight channels are converted. Each of the channels is
converted and the result is placed in a separate result register. Port E bit 0 uses result register ADR1,
Port E bit 1 uses result register ADR2 and so on. Each channel is converted once, then all conversion
activity is halted until a new conversion command is written to the ADCTL control register.
MOTOROLA
9-4
ANALOG-TO-DIGITAL CONVERTER
MC68HC11G5
9.4.4
8-Channel Continuous Scan
Conversions continue to be performed on all eight channels with the ninth conversion being stored
in the ADR1 register (replacing the earlier conversion result for the first channel in the group), the
tenth conversion overwrites ADR2, the eleventh overwrites ADR3, and so on, continuously. Using
this second variation the data in any result register is, at most, eight conversion times old.
9.5
POWER-UP AND CLOCK SELECT
A/D power up is controlled by the ADPU bit in the OPTION register. When ADPU is cleared, power
to the A/D system is removed. When ADPU is set, the A/D system is enabled. A delay of 100
microseconds is required after turning on the A/D converter, to allow the analog bias voltages to
stabilize.
Clock select is controlled by the CSEL bit in the OPTION register. When CSEL is cleared, the A/D
system uses the system E-clock. When CSEL is set, the A/D system uses an internal R-C clock
source, nominally 1.5 MHz, in which case the R-C internal clock should be selected. A delay of 10
milliseconds is required, after changing CSEL from zero to one, to allow the R-C oscillator to start
and internal bias voltages to settle.
When the A/D system is operating with the MCU E-clock, all switching and comparator operations
are synchronized with the MCU clock. This allows the comparator results to be sampled at quiet
clock times to minimise the effect of internal switching noise. As the internal R-C oscillator is
asynchronous with respect to the MCU clock, internal switching noise is more likely to affect the
overall accuracy of the A/D results, when using this oscillator, than when using the E-clock.
9.6
OPERATION IN STOP AND WAIT MODES
If a conversion sequence is still in process when the MC68HC11G5 enters the STOP or WAIT mode,
the conversion of the current channel is suspended. When the MCU resumes normal operation, that
channel is re-sampled and the conversion sequence resumes. As the MCU exits the WAIT mode,
the A/D circuits are stable and valid results can be obtained on the first conversion. However, in
STOP mode the comparator, charge pump and R-C oscillator are turned off. If the MC68HC11G5
exits the STOP mode with a delay (as is normal), there will automatically be enough time for these
circuits to stabilize before the first conversion. If the MC68HC11G5 exits the STOP mode with no
delay (DLY bit in OPTION register equal to zero) and a stable external clock supplied, the user must
allow about 100 microseconds for the A/D circuitry to stabilize and to avoid invalid results.
MC68HC11G5
ANALOG-TO-DIGITAL CONVERTER
MOTOROLA
9-5
9.7
REGISTERS
9.7.1
A/D Control and Status Register (ADCTL)
$1030
7
CCF
6
CONV8
RESET:
Undefined
5
SCAN
4
MULT
3
CD
READ:
Any time.
WRITE:
Any time except writes always clear bit 7.
RESET:
Indeterminate.
2
CC
1
CB
0
CA
ADCTL
CCF — Conversions Complete Flag
This flag bit is set automatically after an A/D conversion cycle (four or eight conversions,
depending on which conversion mode is selected). If a continuous scan mode is
selected, the CCF flag will become set after the first time all four (or eight) registers have
been updated, and it will remain set until the ADCTL register is again written. Each time
the ADCTL register is written, this bit is automatically cleared to zero, any current
conversion is aborted and a new conversion sequence is started.
CONV8 — Convert 8/Convert 4 Select Bit
0 – Convert 4 channels or one channel 4 times (uses 4 result registers).
1 – Convert 8 channels or one channel 8 times, (uses all 8 result registers).
SCAN — Continuous Scan Control
0 – Perform selected number of conversions (4 or 8) and stop.
1 – Convert continuously.
MULT — Multiple Channel/Single Channel Control
0 – Convert single channel selected.
1 – Convert the selected number of channels (4 or 8).
CD, CC, CB, CA — Channel Select Bits
When 4-conversion (CONV8 = 0) and multiple channel (MULT=1) modes are selected,
the CB and CA bits have no meaning or effect, and the CD and CC bits specify which of
four groups of four channels are to be converted. When 8-conversion (CONV8 = 1) and
multiple channel (MULT=1) modes are selected, the CC, CB and CA bits have no
meaning or effect. (Refer to Table 9-1 for a list of the A/D channel assignments.)
MOTOROLA
9-6
ANALOG-TO-DIGITAL CONVERTER
MC68HC11G5
9.7.2
Result Registers (ADR1 – ADR8)
7
6
5
4
3
2
1
0
$1040
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
$1041
BIT7
BIT6
0
0
0
0
0
0
$1042
$1043
BIT15
BIT7
BIT14
BIT6
BIT13
0
BIT12
0
BIT11
0
BIT10
0
BIT9
0
BIT8
0
ADR2
$1044
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
ADR3
$1045
BIT7
BIT6
0
0
0
0
0
0
$1046
$1047
BIT15
BIT7
BIT14
BIT6
BIT13
0
BIT12
0
BIT11
0
BIT10
0
BIT9
0
BIT8
0
ADR4
$1048
$1049
BIT15
BIT7
BIT14
BIT6
BIT13
0
BIT12
0
BIT11
0
BIT10
0
BIT9
0
BIT8
0
ADR5
$104A
$104B
BIT15
BIT7
BIT14
BIT6
BIT13
0
BIT12
0
BIT11
0
BIT10
0
BIT9
0
BIT8
0
ADR6
$104C
$104D
BIT15
BIT7
BIT14
BIT6
BIT13
0
BIT12
0
BIT11
0
BIT10
0
BIT9
0
BIT8
0
ADR7
$104E
BIT15
BIT14
BIT13
BIT12
BIT11
BIT10
BIT9
BIT8
ADR8
$104F
BIT7
BIT6
0
0
0
0
0
0
RESET:
Undefined
READ:
Any time.
WRITE:
Has no meaning or effect.
RESET:
Indeterminate.
ADR1
The eight 10-bit result registers are read-only. In each result register, the 8 high order bits are in one
address location and the remaining 2 low order bits are in bit locations 6 and 7 of the following
address. The 6 unused bits will always read as zeros. This allows a double byte read to be performed
without having to adjust the result.
MC68HC11G5
ANALOG-TO-DIGITAL CONVERTER
MOTOROLA
9-7
This page intentionally left blank
MOTOROLA
9-8
ANALOG-TO-DIGITAL CONVERTER
MC68HC11G5
SECTION 10
PULSE WIDTH MODULATION TIMER
10.1
GENERAL OVERVIEW
The PWM module provides up to four 8-bit pulse width modulated waveforms on the Port H pins.
Channel pairs may be concatenated to create 16-bit PWM outputs. Three clock sources (A, B
and S) give the PWM a wide range of frequencies. Figure 10-1 shows the block diagram of the PWM
module.
Each channel also has a separate 8-bit counter register (PWCNTx), period register (PWPERx), and
duty cycle register (PWDTYx). Resetting the counter and starting the waveform output is controlled
by the occurrence of a match between the period register and the value in the counter. Counters
may also be reset by writing to them. The duty register changes the state of the output during the
period to control the duty cycle of the waveform. The period and duty cycle registers are double
buffered so that, if they are changed while the channel is enabled, the change will not take effect
until the counter rolls over or the channel is disabled. A new period or duty cycle can be forced by
writing to the period or duty cycle register and then writing to the counter.
Four control registers are used to configure the PWM outputs – PWCLK, PWPOL, PWSCAL, and
PWEN. The PCKAx and PCKBx bits in the PWCLK register select the prescale values for the PWM
clock sources. PWCLK also contains the CON34 and CON12 bits which enable the 16-bit PWM
functions. The PWPOL register determines each channel’s polarity (PPOLx bits) and selects the
clock source for each channel (PCLKx bits). The PWSCAL register can be programmed with a
prescale value which is used to derive a scaled clock based on the A clock source. The PWENx bits
in the PWEN register enable or disable the PWM channels.
With PWMs configured for 8-bit mode and E = 2 MHz, PWM signals can be produced from 20 kHz
(1% duty cycle resolution) to less than 5 Hz (approximately 0.4% duty cycle resolution). By
configuring the PWMs for 16-bit mode with E = 2 MHz, PWM periods greater than one minute can
be achieved.
In 16-bit mode, duty cycle resolution of almost 15 parts per million can be achieved (at a PWM
frequency of about 30 Hz). In the same system, a PWM frequency of 1 kHz would correspond to a
duty cycle resolution of 0.05%.
MC68HC11G5
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-1
MCU
E Clock
÷1
÷2
÷4
÷8
÷ 16
÷ 32
÷ 64
÷ 128
PCKB1
PCKB2
PCKB3
8-Bit Compare
=
÷2
Clock S
PWSCAL
PCKA1
PCKA2
reset
Select
8-Bit Counter
Clock A
Clock B
Select
PCLK3
PCLK4
PWEN3
PWEN4
CON34
Clock
Select
CNT4
PCLK1
PCLK2
CNT3
PWEN1
PWEN2
CON12
Clock
Select
CNT2
CNT1
M
U
X
Bit 0
PW1
M
U
X
Bit 1
PW2
PPOL1
S
8-Bit Compare
=
PWDTY1
8-Bit Compare
8-Bit Compare
16-Bit
PWM
Control
=
Q
R
Q
S
Q
PWDTY2
=
PWPER1
8-Bit Compare
=
R
Q
PWPER2
Port H
Pin
Control
PPOL2
reset
CON12
reset
PWCNT1
PWCNT2
8-Bit Compare
=
PWDTY3
8-Bit Compare
PWPER3
8-Bit Compare
PPOL3
Carry
16-Bit
PWM
Control
=
S
Q
R
Q
S
Q
R
Q
PWDTY4
=
8-Bit Compare
=
M
U
X
Bit 2
PW3
M
U
X
Bit 3
PW4
PWPER4
PPOL4
reset
CON34
reset
PWCNT3
PWCNT4
Carry
PWMx
PWDTY
PWPER
Figure 10-1. PWM Timer Module Block Diagram
MOTOROLA
10-2
PULSE WIDTH MODULATION TIMER
MC68HC11G5
10.2
CLOCK SELECTION
There are three available clocks (A, B and S). Clock A can be software-selected to be E, E/
2, E/4 or E/8. Clock B can be software selected to be E, E/2, E/4,..., E/128. The block diagram
of Figure 10-1 depicts the three different clocks and how the scaled clock is created.
The scaled clock (S) uses clock A as an input and divides it with a reloadable counter. This counter
is compared with a user programmable scale value (in the PWSCAL register). When they match,
a pulse is output and the 8-bit counter is reset. The output signal from this circuit is then divided by
two to give clock S. The rates available for clock S, therefore, are software selectable to be clock A
divided by 2 down to clock A divided by 512 in increments of 2.
Each PWM timer channel can be driven by one of two clocks, selected in software: Channels 1 and 2
can use clock A or clock S; Channels 3 and 4 can use clock B or clock S.
Writing to PWSCAL causes the 8-bit counter to be reset to $00. Otherwise, when changing from a
low rate to a higher rate, it would be possible for the counter to miss the new value and have to go
all the way to $FF and wrap back around before counting at the proper rate. Forcing the counter to
$00 every time it is written prevents this.
10.3
16-BIT PWM FUNCTION
The PWCLK register contains two control bits, each of which is used to concatenate a pair of PWM
channels into one 16-bit channel. Concatenation of channels 3 and 4 is controlled by the CON34
bit; similarly, channels 1 and 2 are concatenated using the CON12 bit.
When channels 3 and 4 are concatenated, channel 3 registers become the high order bytes of the
double byte channel. Reading the counter high order byte causes the low order byte to be latched
for one cycle, to guarantee that double byte reads will be accurate. Writing to the low byte of the
counter (channel 4) causes the entire counter to be reset. Writing to the upper byte of the counter
has no effect.
Similarly, when channels 1 and 2 are concatenated, channel 1 registers become the high order bytes
of the double byte channel.
The 16-bit duty register and period register are obtained by concatenating the two 8-bit duty registers
and period registers, respectively. Writing to these registers takes twice as many write cycles as for
the 8-bit PWM. The 16-bit PWM circuit has secondary buffers internally, and the user should write
to these 16-bit registers using 16-bit write instructions or high byte to low byte sequential write
instructions. During the two-byte write sequence, the secondary buffer will not be loaded from the
16-bit register. The 16-bit duty and period registers can be written to at any time; the written value
will take effect from the next cycle of the PWM period.
MC68HC11G5
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-3
10.4
BOUNDARY CASES
The following boundary conditions cause these results:
If PWDTYx = $00, PWPERx > $00, PPOLx = 0;
the output is always high.
If PWDTYx = $00, PWPERx > $00, PPOLx = 1;
the output is always low.
If PWDTYx = or > PWPERx, PPOLx = 0;
the output is always low.
If PWDTYx = or > PWPERx, PPOLx = 1;
the output is always high.
If PWPERx = $00 & PPOLx = 0;
output x is always low.
If PWPERx = $00 & PPOLx = 1;
output x is always high.
10.5
PWM REGISTERS
10.5.1
Counter Registers (PWCNTX)
Each channel has its own counter. Each counter may be read at any time without affecting the count
or the operation of the PWM channel. Writing to a counter causes the counter to be reset to $00.
Generally, writing to a counter is done before the counter is enabled. Writing to a counter can also
be done while it is enabled (counting), but this may cause a truncated PWM period.
7
6
5
4
3
2
1
0
$1064
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWCNT1
$1065
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWCNT2
$1066
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWCNT3
$1067
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWCNT4
READ:
Any time.
WRITE:
Forces value to $00.
RESET:
$00.
When a channel becomes enabled (i.e. when PWENx is written from 0 to 1), the associated PWM
counter starts to count from the value in this PWCNTx register, using whichever clock has been
selected for that channel.
MOTOROLA
10-4
PULSE WIDTH MODULATION TIMER
MC68HC11G5
10.5.2
Period Registers (PWPERX)
There is one period register for each channel. The value in this register determines the period of the
associated PWM timer channel.
In terms of the internal PWM circuitry, this register is connected to a buffer which compares with the
counter register directly. The period value in this register is loaded into the buffer when the counter
is cleared by the termination of the previous period or by a write to the counter. This register can be
written at any time, and the written value will take effect from the next PWM timer cycle. Reading
this register returns the most recent value written.
7
6
5
4
3
2
1
0
$1068
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWPER1
$1069
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWPER2
$106A
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWPER3
$106B
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWPER4
READ:
Any time.
WRITE:
Any time.
RESET:
$FF.
10.5.3
Duty Registers (PWDTYx)
There is one duty register for each channel. The value in this register determines the duty cycle of
the associated PWM timer channel.
In terms of the internal PWM circuitry, this register is connected to a buffer which compares with the
counter directly. The duty value in this register is loaded into the second buffer when the counter
is cleared by previous period termination or the counter write operation. This register can be written
at any time, and the written value will take effect from the next PWM timer cycle. Reading this register
returns the most recent value written.
MC68HC11G5
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-5
Note:
If the duty register is greater than or equal to the value in the period register there will be
no duty change in state. In addition, if the duty register is set to $00 the output will always
be in the state which would normally be the state changed to at the duty change of state.
Refer to the “Boundary Cases” section for more information on this.
7
6
5
4
3
2
1
0
$106C
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWDTY1
$106D
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWDTY2
$106E
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWDTY3
$106F
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
PWDTY4
READ:
Any time.
WRITE:
Any time.
RESET:
$FF.
10.5.4
Clock Select Register (PWCLK)
$1060
7
CON34
6
CON12
5
PCKA2
4
PCKA1
3
0
2
PCKB3
1
PCKB2
0
PCKB1
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00.
PWCLK
CON34 — Concatenate channels 3 and 4
1 – Channels 3 and 4 are concatenated to create one 16-bit PWM channel. (Channel
3 becomes the high order byte and channel 4 becomes the low order byte. The
channel 4 output is used as the output for this 16-bit PWM (bit 3 of Port H)).
0 – Channels 3 and 4 are separate 8-bit PWM channels.
MOTOROLA
10-6
PULSE WIDTH MODULATION TIMER
MC68HC11G5
CON12 — Concatenate channels 1 and 2
1 – Channels 1 and 2 are concatenated to create one 16-bit PWM channel. (Channel
1 becomes the high order byte and channel 2 becomes the low order byte. The
channel 2 output is used as the output for this 16-bit PWM (bit 1 of Port H)).
0 – Channels 1 and 2 are separate 8-bit PWM channels.
PCKA2, PCKA1 — Prescaler for clock A
Clock A is one of two clock sources which may be used for channels 1 & 2. These two
bits determine the rate of clock A.
PCKA2
PCKA1
Value of Clock A
0
0
E
0
1
E/2
1
0
E/4
1
1
E/8
PCKB3, PCKB2, PCKB1 — Prescaler for clock B
Clock B is one of two clock sources which may be used for channels 3 & 4. These three
bits determine the rate of clock B.
MC68HC11G5
PCKB3
PCKB2
PCKB1
Value of Clock B
0
0
0
E
0
0
1
E/2
0
1
0
E/4
0
1
1
E/8
1
0
0
E/16
1
0
1
E/32
1
1
0
E/64
1
1
1
E/128
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-7
10.5.5
Polarity Select Register (PWPOL)
Each channel has a polarity bit (PPOLx) to start the cycle with a high signal or with a low signal. This
is shown on the block diagram as a multiplex select of either the Q output or the Q output of the PWM
output flip-flop. When one of the bits in the PWPOL register is set, the associated PWM channel
output is high at the beginning of the clock cycle, then goes low when the duty count is reached.
$1061
7
PCLK4
6
PCLK3
5
PCLK2
4
PCLK1
3
PPOL4
2
PPOL3
1
PPOL2
0
PPOL1
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00
PWPOL
PCLK4 — Pulse Width Channel 4 Clock Select
1 – The clock source for PWM channel 4 is Clock S. (Clock S equals Clock A divided
by two times the value (plus one) in the PWSCAL register.)
0 – Clock B is the clock source for PWM channel 4.
PCLK3 — Pulse Width Channel 3 Clock Select
1 – The clock source for PWM channel 3 is Clock S.
0 – Clock B is the clock source for PWM channel 3.
PCLK2 — Pulse Width Channel 2 Clock Select
1 – The clock source for PWM channel 2 is Clock S.
0 – Clock A is the clock source for PWM channel 2.
PCLK1 — Pulse Width Channel 1 Clock Select
1 – The clock source for PWM channel 1 is Clock S.
0 – Clock A is the clock source for PWM channel 1.
Note:
While register bits PCLK1 – 4 may be written at any time, if a clock select is changed while
a PWM signal is being generated, a truncated pulse may occur during the transition.
PPOL4 — Pulse Width Channel 4 Polarity
1 – PWM channel 4 output is high at the beginning of the clock cycle, then goes low
when the duty count is reached.
0 – PWM channel 4 output is low at the beginning of the clock cycle, then goes high
when the duty count is reached.
MOTOROLA
10-8
PULSE WIDTH MODULATION TIMER
MC68HC11G5
PPOL3 — Pulse Width Channel 3 Polarity
1 – PWM channel 3 output is high at the beginning of the clock cycle, then goes low
when the duty count is reached.
0 – PWM channel 3 output is low at the beginning of the clock cycle, then goes high
when the duty count is reached.
PPOL2 — Pulse Width Channel 2 Polarity
1 – PWM channel 2 output is high at the beginning of the clock cycle, then goes low
when the duty count is reached.
0 – PWM channel 2 output is low at the beginning of the clock cycle, then goes high
when the duty count is reached.
PPOL1 — Pulse Width Channel 1 Polarity
1 – PWM channel 1 output is high at the beginning of the clock cycle, then goes low
when the duty count is reached.
0 – PWM channel 1 output is low at the beginning of the clock cycle, then goes high
when the duty count is reached.
10.5.6
Scale Register (PWSCAL)
$1062
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time (causes clock counter to be reset to $00).
RESET:
$00
PWSCAL
Each of the PWM channels can select clock S (scaled) as its input clock. Clock S may be selected
for channel x by writing a one to the control bit PCLKx. Clock S is generated by taking clock A,
dividing it by the value in this PWSCAL register and dividing that by two. When PWSCAL = $00, clock
A is divided by 256 then divided by two to generate clock S. In test mode, the PWSCAL register can
be used to read the value of clock S (scaled) if the TPWSL bit in the TEST1 register is set.
MC68HC11G5
PULSE WIDTH MODULATION TIMER
MOTOROLA
10-9
10.5.7
Enable Register (PWEN)
Each timer has an enable bit (PWENx) to start its waveform output. Writing any of these PWENx
bits to one causes the associated Port H line to become an output regardless of the state of the
associated DDR bit. This does not change the state of the DDR bit and, when PWENx returns to
zero, the DDR bit again controls the I/O state. On the front end of the PWM timer the clock is enabled
to the PWM circuit by the PWENx enable bit being high. A synchronizing circuit guarantees that the
clock will only be enabled or disabled at an edge.
$1063
7
0
6
0
5
0
4
0
RESET:
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00.
3
2
1
0
PWEN4 PWEN3 PWEN2 PWEN1
0
0
0
PWEN
0
PWEN4 — Pulse Width Channel 4 Enable
1 – PWM channel 4 is enabled. The pulse modulated signal becomes available at
Port H bit 3 when its clock source begins its next cycle.
0 – PWM channel 4 is disabled.
PWEN3 — Pulse Width Channel 3 Enable
1 – PWM channel 3 is enabled. The pulse modulated signal becomes available at
Port H bit 2 when its clock source begins its next cycle.
0 – PWM channel 3 is disabled.
PWEN2 — Pulse Width Channel 2 Enable
1 – PWM channel 2 is enabled. The pulse modulated signal becomes available at
Port H bit 1 when its clock source begins its next cycle.
0 – PWM channel 2 is disabled.
PWEN1 — Pulse Width Channel 1 Enable
1 – PWM channel 1 is enabled. The pulse modulated signal becomes available at
Port H bit 0 when its clock source begins its next cycle.
0 – PWM channel 1 is disabled.
MOTOROLA
10-10
PULSE WIDTH MODULATION TIMER
MC68HC11G5
SECTION 11
EVENT COUNTER
11.1
INTRODUCTION
The event counter consists of two distinct functional blocks. One block functions as an 8-bit pulse
accumulator unit (PA), the other as an 8-bit pulse width modulation unit (PWM). Each unit has its
own 8-bit counter and two 8-bit compare registers.
Four software selectable operating modes provide different configurations of the PA and PWM, their
interconnection and their combined operation. (The operating mode is selected using the event
counter mode select bits, EVMDA and EVMDB in the event counter lock register (EVCLK)). All four
modes provide programmable PWM period, duty cycle and polarity. Note that these PWM circuits
differ from the main PWM section in that these can be driven by an external signal. A simplified block
diagram of each mode is shown in Figure 11-1.
In mode 0, the PA unit can modify the PWM output by adding a programmable offset to the
input signal and by controlling the clearing of the PWM unit, thereby controlling the period of
the output signal.
In mode 1, the event counter operates as separate PWM and PA units. The two units are not
interconnected and operate completely independently of each other, providing standard
programmable PWM and PA functions.
In mode 2, the PA unit counts the PWM output signal periods, which may be of varying duration and
modulation.
In mode 3, the PA unit acts as a programmable 8-bit (1 – 256 clock) prescaler for the PWM unit.
The 8-bit counters in the PWM and PA units can be driven by an external clock or by a derivative
of the E-clock (E or scaled E), generated by the on-chip time-base counter. The clock source is
controlled by two input selectors (INPUT1 and INPUT2). Depending on the mode of operation
selected, the input selectors are used to determine the following:
1)
Clock source,
2)
Active edge of the external signal (which may be used as a clock),
3)
The gated input of the internal clock,
4)
Counter clear
One output selector is used to control the polarity of the PWM output signal.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-1
Mode 0: Pulse Accumulator modifies PWM output
by adding offset and controlling the clearing
of the PWM
Mode 1: PA and PWM are completely independent
Mode 2: PA Counts the PWM periods (which may
be of variable duration and modulation)
*
INPUT2
PA
*
INPUT1
*
INPUT2
PA
*
INPUT1
PWM
*
INPUT2
●
PWM
OUTPUT
OUTPUT
PA
Mode 4: PA acts as programmable 8-bit prescaler
for PWM unit
*
INPUT1
PWM
*
INPUT2
PA
PWM
*
*
OUTPUT
OUTPUT
INPUT1
INPUT1 and INPUT2 can be driven from the E-clock, a second value of the E-clock or from
external signals on the EVI2 and EVI1 input pins. When EVI2 or EVI1 is not being used for
this purpose they may be used as general I/O pins (PH4 and PH5).
Figure 11-1. Event Counter Operating Modes
Each unit can generate an interrupt signal (referred to as EVENT1 or EVENT2 in the following
discussion) on a counter match with one of its two compare registers.
The PWM unit is comprised of counter 1 (EVCNT1), two compare registers (ECMP1A and
ECMP1B), an input selector (INPUT1) and an output selector. The PA unit is comprised of Counter
2 (EVCNT2), two compare registers (ECMP2A and ECMP2B) and an input selector (INPUT2).
MOTOROLA
11-2
EVENT COUNTER
MC68HC11G5
11.2
MODE 0: 8-BIT PWM WITH SELECTABLE PHASE SHIFT
In mode 0, the event counter operates as an 8-bit PWM unit with an 8-bit phase shifter. If mode 0
is selected (EVMDB = 0, EVMDA = 0), then the elements of the event counter are configured as
shown in Figure 11-2.
EVI2 (PH4)
CLEAR
EVCNT2
INPUT2
8
X
ECMP2A
8
Z
EVENT2
ECMP2B
CLEAR
EVI1(PH5)
EVCNT1
E
E/2
E/4
E/8
E/16
E/32
E/64
E/128
8
ECMP1A
Y
EVENT1
8
INPUT1
ECMP1B
R
X'
(PH6) EVO
S
EVI2
EVCNT2
EVO
X
X'
Y-X'
Y
Y-X'
Figure 11-2. 8-bit PWM with Selectable Phase Shift (Mode 0)
11.2.1
Operation of PWM and PA Unit in Mode 0
The period of the modulated output is controlled by an external signal applied to the EVI2 pin. The
active edge of this input signal is selected via the INPUT2 selector. This input signal clears EVCNT2
in the PA unit and starts the 8-bit phase shift sequence.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-3
The two counter registers (EVCNT1 and EVCNT2) are clocked by the same signal via the INPUT1
selector. This clock signal can be the E-clock, a scaled E-clock or an external signal applied to the
EVI1 pin. If the clock signal is the E-clock or a derivative, an external gating signal can be applied
to EVI1. If EVI1 is not used for clock or gate, it can be used as a normal I/O pin (PH5).
The 8-bit phase shift value (X) is stored in ECMP2A (in the PA unit). When the count in EVCNT2
reaches this value, the successful compare causes a clearing signal to be applied to EVCNT1 in the
PWM unit and starts the PWM sequence.
The value of the output pulse width (Y) is stored in ECMP1A, however the start time and the duration
of this pulse can be modified by a skew value (X’) which is stored in ECMP1B. If no skew is included,
i.e. ECMP1B is set to zero, then a compare occurs when EVCNT1 is cleared, and the output signal
changes state immediately after the initial phase shift period X introduced by the PA unit. The effect
of storing a skew value (X’) in ECMP1B is to delay the leading edge of the PWM output pulse by the
phase shift plus the skew value (X+X’).
The trailing edge of the output pulse is generated when there is a match between EVCNT1 and
ECMP1A (X + Y). Note that the skew value does not affect the timing of the trailing edge of the output
pulse, but only the leading edge. Consequently the output pulse width is reduced by the skew value
from Y to Y-X’. A maskable interrupt signal EVENT1 is generated when there is a match between
EVCNT1 and ECMP1A.
A clearing signal on the EVI2 pin clears EVCNT2 in the PA unit and restarts the sequence.
ECMP2B can be used to generate an interrupt signal, EVENT2, when EVCNT2 accumulates a
desired number of clock pulses.
11.2.2
Register Functions in Mode 0
11.2.2.1
Counter 1 (EVCNT1)
This counter drives the PWM section of the event counter. It is cleared by a successful comparison
between ECMP2A and EVCNT2. The source chosen by input selector INPUT1 is used as the clock
input to both counters (EVCNT1 and EVCNT2). The width and time of the output pulse is determined
by the value in this counter matching the values in ECMP1A and ECMP1B.
11.2.2.2
Compare Register 1A (ECMP1A); (Y)
This compare register holds the nominal value of the output pulse width. Note that the actual output
pulse width value will be equal to the value contained in ECMP1A minus the skew value which is
held in event compare register 1B (ECMP1B). An interrupt signal, EVENT1 is generated when there
is a match between ECMP1A and EVCNT1.
11.2.2.3
Compare Register 1B (ECMP1B); (X’)
This compare register holds a value which adjusts the phase skew between the external signal (on
EVI2) and the leading edge of the desired output signal. If the value in this register is zero, then the
actual pulse width depends only on the value Y in ECMP1A. If the value in this register is equal to
MOTOROLA
11-4
EVENT COUNTER
MC68HC11G5
the value Y in ECMP1A, the event output (EVO) will always be low (when EVPOL = 0). Note that
this skew value should be a smaller value than the minimum value of the pulse width Y. (If the value
in this register is larger than the value Y in ECMP1A, it is possible to miss a pulse in one cycle and
the following cycle will be reversed in polarity cycle, which is equivalent to exchanging X’ and Y in
Figure 11-2.).
11.2.2.4
Counter 2 (EVCNT2)
This counter is cleared by the external signal on the EVI2 pin. The source chosen by input selector
INPUT1 is used as the clock input to both counters (EVCNT1 and EVCNT2). This counter is used
to control the amount of phase shift between the external signal’s active edge and the start of the
PWM output signal, using ECMP2A. A successful compare with compare register 2B will cause an
interrupt request 2 (EVENT2) to be generated.
11.2.2.5
Compare Register 2A (ECMP2A); (X)
This compare register holds the value of the phase shift between the external signal active edge (or
level) and the PWM output signal. Note that this phase shift value is added to the skew value held
in ECMP1B to determine the timing of the leading edge of the PWM output pulse. If the value in this
register is zero, then the active edge of the external signal on EVI2 will reset EVCNT1 immediately
and there will be no phase shift, only skew.
11.2.2.6
Compare Register 2B (ECMP2B)
This compare register can be used to generate an interrupt when the PA unit has accumulated a
desired number of clock pulses. When a match occurs between EVCNT2 and ECMP2B, an interrupt
signal EVENT2 is generated which, if enabled, will interrupt the CPU.
11.2.2.7
Input Unit 1 (EVI1)
This unit selects the clock source for EVCNT1 and EVCNT2. If the input signal on the EVI1 pin (PH5)
is used as a clock source, this unit will select the rising edge, falling edge or both edges of the input
signal. If the E-clock or a scaled E-clock is selected as the clock source, this unit controls the active
gated input level which inhibits counting. Even if PH5 is used for general purpose I/O, this unit is able
to select the pass mode (EVI1C = 0, EVI1B = 0, EVI1A = 1).
11.2.2.8
Input Unit 2 (EVI2)
This unit selects the active edge or level of the input signal on the EVI2 pin (PH4) which will reset
EVCNT2 (to zero).
11.2.2.9
Output Unit (EVO)
This unit controls the polarity of the PWM output signal. With the EVOEN (Event Output Enable) bit
in the EVCTL register set to one, the EVPOL (Event Output Polarity) bit determines the polarity of
the PWM output.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-5
11.3
MODE 1: 8-BIT PWM AND PULSE ACCUMULATOR
In mode 1, the event counter operates as two independent 8-bit pulse accumulators or as one 8bit pulse accumulator and one 8-bit PWM. The two counters work independently of each other. If
mode 1 is selected (EVMDB = 0, EVMDA = 1), then the elements of the event counter are configured
as shown in Figure 11-3.
CLEAR
EVI2 (PH4)
EVCNT2
8
E
ECMP2A
E
E/2
E/4
E/8
E/16
E/32
E/64
E/128
INPUT2
8
EVENT2
ECMP2B
EVENT1
CLEAR
EVCNT1
EVI1(PH5)
8
ECMP1A
8
R
INPUT1
(PH6) EVO
ECMP1B
S
Figure 11-3. 8-bit PWM and Pulse Accumulator (Mode 1)
MOTOROLA
11-6
EVENT COUNTER
MC68HC11G5
Both units can be driven by the E-clock, a scaled E-clock or by external signals applied to the EVI1
and EVI2 pins. However, note that only one scaled value of the E-clock can be selected. For
example, if E/4 is selected as the clock source for EVCNT1, the only E-clock derivatives that can
be chosen as the clock source for EVCNT2 are E and E/4. Alternatively, if E/4 is selected to drive
EVCNT2, then E/4 is the only E-clock derivative that can be selected to drive EVCNT1.
11.3.1
Operation of Pulse Width Modulation Unit in Mode 1
The PWM unit can be clocked by the E-clock, a scaled E-clock, or an external signal applied to the
EVI1 (PH5) pin. Alternatively an external signal on EVI1 can be used to gate the E-clock or scaled
E-clock signal to the counter EVCNT1. The clock source is selected via the INPUT1 selector.
The period of the PWM output signal is determined by the value stored in ECMP1A. When a match
occurs between this compare register and the counter register, EVCNT1, the output unit EVO is
reset and EVCNT1 is cleared (to zero). At the same time, an interrupt signal EVENT1 is generated
which, if enabled, interrupts the CPU.
The duty cycle of the PWM output signal is determined by the relationship between the values stored
in ECMP1B and ECMP1A. The value stored in ECMP1B is the number of clock pulses to be
accumulated by EVCNT1 before the output signal changes state. The output signal then remains
in the new state for the remainder of the period, i.e. until EVCNT1 reaches the value stored in
ECMP1A. The duty cycle can be expressed as a percentage of the period by the following equation:
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
The PWM unit will also work as a pulse accumulator by switching off the output signal to the EVO
pin (PH6) and ignoring ECMP1B.
11.3.2
Operation of Pulse Accumulator Unit in Mode 1
The PA unit can be clocked by the E-clock, a scaled E-clock, or an external signal applied to the EVI2
(PH4) pin. Alternatively an external signal on EVI2 can be used to gate the E-clock or scaled E-clock
signal to the counter EVCNT1. The clock source is selected via the INPUT2 selector.
EVCNT2 counts the pulses coming from the INPUT2 selector. It is cleared by a successful
comparison between itself and the compare register ECMP2A. ECMP2A can be programmed with
any 8-bit value to control the time when the counter is cleared.
ECMP2B can be used to generate an interrupt signal EVENT2 after a required number of input
pulses have been accumulated by EVCNT2. If enabled, EVENT2 will interrupt the CPU.
11.3.3
Register Functions in Mode 1
11.3.3.1
Counter 1 (EVCNT1)
EVCNT1 counts the number of pulses coming from the INPUT1 selector. It is cleared by a successful
comparison between itself and ECMP1A.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-7
11.3.3.2
Compare Register 1A (ECMP1A)
This compare register holds the value of the PWM period which determines when interrupt 1
(EVENT1) occurs. On a successful comparison with EVCNT1, it generates EVENT1, clears
EVCNT1 and resets output EVO to zero (when EVPOL = 0).
11.3.3.3
Compare Register 1B (ECMP1B)
This compare register holds the duty value which determines when the output (EVO) is set to one
(when EVPOL = 0). The duty cycle can be expressed as a percentage of the period by the following
equation:
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
11.3.3.4
Counter 2 (EVCNT2)
EVCNT2 counts the number of pulses coming from the INPUT2 selector. It is cleared by a successful
comparison between itself and ECMP2A.
11.3.3.5
Compare Register 2A (ECMP2A)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before
EVCNT2 is cleared to zero.
11.3.3.6
Compare Register 2B (ECMP2B)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before an
interrupt signal EVENT2 is generated. If enabled, EVENT2 will interrupt the CPU.
11.3.3.7
Input Unit 1 (EVI1)
This input unit selects the clock source for EVCNT1. If the input signal EVI1 (PH5) is used as a clock
source, this unit will select the rising edge, falling edge or both edges of the input signal. If the timebase counter is used as a clock source, this unit will select the active gated input level which inhibits
counting while this input signal is at the active level.
11.3.3.8
Input Unit 2 (EVI2)
This input unit selects the clock source for EVCNT2. If the input signal EVI2 (PH4) is used as a clock
source, this unit will select the rising edge or falling edge of the input signal. If the time base counter
is used as a clock source, this unit will select the active gate input level which inhibits counting while
this input signal is at the active level. Even if the time-base counter has selected one of the eight
clock rates (E, E/2, E/4, E/8, E/16, E/32, E/64, or E/128), this input selector can select the E-clock
independently as its clock source.
MOTOROLA
11-8
EVENT COUNTER
MC68HC11G5
11.3.3.9
Output Unit (EVO)
This unit controls the output signal from the PWM unit. If the EVOEN bit in the EVCTL register is set
to one, the EVO unit is enabled. The state of the EVPOL bit in the EVCTL register then determines
the polarity of the event output. If EVO is not required for pulse width modulation, the EVOEN bit
should be reset to zero to disable the EVO unit and to allow pin PH6 to be used for general purpose
I/O.
11.4
MODE 2: 8-BIT PWM WITH PERIOD COUNTER
In mode 2, the event counter operates as an 8-bit PWM unit and an 8-bit counter (the PA unit)
which increments at the end of each period of the PWM unit. If mode 2 is selected (EVMDB = 1,
EVMDA = 0), then the elements of the event counter are configured as shown in Figure 11-4.
CLEAR
EVCNT2
8
E
E/2
E/4
E/8
E/16
E/32
E/64
E/128
ECMP2A
8
EVENT2
ECMP2B
EVENT1
CLEAR
EVCNT1
EVI1(PH5)
8
ECMP1A
8
R
INPUT1
(PH6) EVO
ECMP1B
S
Figure 11-4. 8-bit PWM with Period Counter (Mode 2)
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-9
The only difference between this mode and mode 1 lies in the clock source used to drive the counter
in the PA unit (EVCNT2). In mode 1, the clock signal comes via the INPUT1 selector and is either
derived from the E-clock (gated or ungated) or an external signal. In mode 2, the signal which results
from a successful comparison between EVCNT1 and ECMP1A in the PWM unit is used to drive
EVCNT2 in the PA unit. This is the same signal which clears EVCNT1, thereby ending the PWM
period. EVCNT2, therefore, counts the number of periods completed by the PWM unit.
11.4.1
Operation of Pulse Width Modulation Unit in Mode 2
The PWM unit can be clocked by the E-clock, a scaled E-clock, or an external signal applied to the
EVI1 (PH5) pin. Alternatively an external signal on EVI1 can be used to gate the E-clock or scaled
E-clock signal to the counter EVCNT1. The clock source is selected via the INPUT1 selector.
The period of the PWM output signal is stored in ECMP1A. When a match occurs between this
compare register and the counter register, EVCNT1, the output unit EVO is reset, EVCNT1 is
cleared (to zero) and EVCNT2 in the PA is incremented by one. At the same time, an interrupt signal
EVENT1 is generated which, if enabled, interrupts the CPU.
The duty cycle of the PWM output signal is stored in ECMP1B. When a match occurs between this
compare register and EVCNT1, the PWM output signal changes state (from zero to one or from one
to zero depending on the polarity selected by the output unit.
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
The PWM unit will also work as a pulse accumulator by switching off the output signal to the EVO
pin (PH6) and ignoring ECMP1B.
11.4.2
Operation of Pulse Accumulator Unit in Mode 2
The PA unit is clocked each time there is a successful comparison between EVCNT1 and ECMP1A
in the PWM unit, i.e. at the end of each PWM period.
EVCNT2 counts the pulses coming from the PWM unit. It is cleared by a successful comparison
between itself and the compare register ECMP2A. ECMP2A can be programmed with any 8-bit
value to control the time when the counter is cleared.
ECMP2B can be used to generate an interrupt signal EVENT2 after a required number of input
pulses have been accumulated by EVCNT2. If enabled, EVENT2 will interrupt the CPU.
11.4.3
Register Functions in Mode 2
11.4.3.1
Counter 1 (EVCNT1)
EVCNT1 counts the number of pulses coming from the INPUT1 selector. It is cleared by a successful
comparison between itself and ECMP1A.
MOTOROLA
11-10
EVENT COUNTER
MC68HC11G5
11.4.3.2
Compare Register 1A (ECMP1A)
This compare register holds the value of the PWM period which determines when interrupt 1
(EVENT1) occurs. On a successful comparison with EVCNT1, it generates EVENT1, clears
EVCNT1, resets output EVO to zero (when EVPOL = 0) and clocks EVCNT2 in the PA unit.
11.4.3.3
Compare Register 1B (ECMP1B)
This compare register holds the PWM duty value which determines when the output (EVO) is set
to one (when EVPOL = 0).
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
11.4.3.4
Counter 2 (EVCNT2)
EVCNT2 counts the number of pulses coming from the PWM unit. It is cleared when a successful
comparison occurs between itself and ECMP2A.
11.4.3.5
Compare Register 2A (ECMP2A)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before
EVCNT2 is cleared to zero.
11.4.3.6
Compare Register 2B (ECMP2B)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before an
interrupt signal EVENT2 is generated. If enabled, EVENT2 will interrupt the CPU.
11.4.3.7
Input Unit 1 (EVI1)
This input unit selects the clock source for EVCNT1. If the input signal EVI1 (PH5) is used as a clock
source, this unit will select the rising edge, falling edge or both edges of the input signal. If the time
base counter is used as a clock source, this unit will select the active gated input level which inhibits
counting while this input signal is at the active level.
11.4.3.8
Input Unit 2 (EVI2)
This unit is not used and the EVI2 pin (PH4) can be used as a general purpose I/O pin.
11.4.3.9
Output Unit (EVO)
This unit controls the output signal from the PWM unit. If the EVOEN bit in the EVCTL register is set
to one, the EVO unit is enabled. The state of the EVPOL bit in the EVCTL register then determines
the polarity of the event output. If EVO is not required for PWM, the EVOEN bit should be reset to
zero to disable the EVO unit and to allow pin PH6 to be used for general purpose I/O.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-11
11.5
MODE 3: 8-BIT PWM WITH 256 CLOCK PRESCALER
In mode 3, the event counter operates as an 8-bit PWM unit with a software programmable 8-bit
clock prescaler (the PA unit). If mode 3 (EVMDB = 1, EVMDA = 1) is selected then the elements of
the event counter are configured as shown in Figure 11-5.
The only difference between this mode and mode 1 lies in the clock source used to drive the counter
in the PWM unit (EVCNT1). In mode 1, the clock signal comes via the INPUT2 selector and is either
derived from the E-clock (gated or ungated) or an external signal. In mode 3, the signal which results
from a successful comparison between EVCNT2 and ECMP2A in the PA unit is used to drive
EVCNT1 in the PWM unit. EVCNT1, therefore, increments by one every time the value in EVCNT2
reaches the value programmed into ECMP2A. In other words, the PA unit acts as a prescaler to the
PWM unit, its division ratio being the 8-bit value in ECMP2A.
11.5.1
Operation of Pulse Width Modulation Unit in Mode 3
The PWM unit is clocked each time there is a successful comparison between EVCNT2 and
ECMP2A in the PA unit, i.e. at the end of each PA counting period.
The period of the PWM output signal is stored in ECMP1A. When a match occurs between this
compare register and the counter register, EVCNT1, the output unit EVO is reset and EVCNT1 is
cleared (to zero). At the same time, an interrupt signal EVENT1 is generated which, if enabled,
interrupts the CPU.
The duty cycle of the PWM output signal is stored in ECMP1B. When a match occurs between this
compare register and EVCNT1, the PWM output signal changes state (from zero to one or from one
to zero depending on the polarity selected by the output unit.
MOTOROLA
11-12
EVENT COUNTER
MC68HC11G5
CLEAR
EVI2 (PH4)
EVCNT2
8
ECMP2A
E
E/2
E/4
E/8
E/16
E/32
E/64
E/128
INPUT2
8
EVENT2
ECMP2B
EVENT1
CLEAR
EVCNT1
8
ECMP1A
8
R
(PH6) EVO
ECMP1B
S
Figure 11-5. 8-bit PWM with 256 Clock Prescaler (Mode 3)
The PWM unit will also work as a pulse accumulator by switching off the output signal to the EVO
pin (PH6) and ignoring ECMP1B.
11.5.2
Operation of Pulse Accumulator Unit in Mode 3
The PA unit can be clocked by the E-clock, a scaled E-clock, or an external signal applied to the EVI2
(PH4) pin. Alternatively an external signal on EVI2 can be used to gate the E-clock or scaled E-clock
signal to the counter EVCNT2. The clock source is selected via the INPUT2 selector.
EVCNT2 counts the clock pulses coming from the INPUT2 selector. It is cleared by a successful
comparison between itself and the compare register ECMP2A. ECMP2A can be programmed with
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-13
any 8-bit value to define when the counter is cleared and the PWM clocked. It causes the PA unit
to act as a prescaler for the PWM by dividing the clock signal, coming via INPUT2, by any value
between 1 and 256.
ECMP2B can be used to generate an interrupt signal EVENT2 after a required number of input
pulses have been accumulated by EVCNT2. If enabled, EVENT2 will interrupt the CPU.
11.5.3
Register Functions in Mode 3
11.5.3.1
Counter 1 (EVCNT1)
EVCNT1 counts the number of pulses coming from the PA unit. It is cleared by a successful
comparison between itself and ECMP1A.
11.5.3.2
Compare Register 1A (ECMP1A)
This compare register holds the value of the PWM period which determines when interrupt 1
(EVENT1) occurs. On a successful comparison with EVCNT1, it generates EVENT1, clears
EVCNT1 and resets output EVO to zero (when EVPOL = 0).
11.5.3.3
Compare Register 1B (ECMP1B)
This compare register holds the PWM duty value which determines when the output (EVO) is set
to one (when EVPOL = 0).
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
11.5.3.4
Counter 2 (EVCNT2)
EVCNT2 counts the number of clock pulses coming from the INPUT2 selector. It is cleared when
a successful comparison occurs between itself and ECMP2A.
11.5.3.5
Compare Register 2A (ECMP2A)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before
EVCNT2 is cleared to zero.
11.5.3.6
Compare Register 2B (ECMP2B)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before an
interrupt signal EVENT2 is generated. If enabled, EVENT2 will interrupt the CPU.
11.5.3.7
Input Unit 1 (EVI1)
This unit is not used and the EVI1 pin (PH5) can be used as a general purpose I/O pin.
MOTOROLA
11-14
EVENT COUNTER
MC68HC11G5
11.5.3.8
Input Unit 2 (EVI2)
This input unit selects the clock source for EVCNT2. If the input signal EVI2 (PH4) is used as a clock
source, this unit will select the rising edge or falling edge of the input signal. If the time base counter
is used as a clock source, this unit will select the active gate input level which inhibits counting while
this input signal is at the active level. Even if the time base counter has selected one of the eight clock
rates (E, E/2, E/4, E/8, E/16, E/32, E/64, or E/128), this input selector can select the E-clock
independently as its clock source.
11.5.3.9
Output Unit (EVO)
This unit controls the output signal from the PWM unit. If the EVOEN bit in the EVCTL register is set
to one, the EVO unit is enabled. The state of the EVPOL bit in the EVCTL register then determines
the polarity of the event output. If EVO is not required for PWM, the EVOEN bit should be reset to
zero to disable the EVO unit and to allow pin PH6 to be used for general purpose I/O.
11.6
EVENT COUNTER REGISTERS
11.6.1
Counter Clock Register (EVCLK)
7
6
$1070
RESET:
READ:
Any time.
WRITE:
Any time.
RESET:
$00.
5
4
3
EVMDB EVMDA
0
0
0
0
2
1
0
EVCKC EVCKB EVCKA
0
0
0
EVCLK
0
EVMDB, EVMDA — Event Counter Mode bits
These two bits determine which event counter mode will be used.
EVMDB
EVMDA
MODE
0
0
1
1
0
1
0
1
0
1
2
3
(8-bit PWM with selectable phase shift)
(8-bit PWM and 8-bit pulse accumulator)
(8-bit PWM with period counter)
(8-bit PWM with 256 clock prescaler)
EVCKC, EVCKB, EVCKA — Event Counter Prescaler bits
These three bits control the time-base counter. They select the prescaler value used to
scale the E-clock before driving the event counters.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-15
EVCKC
EVCKB
EVCKA
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
11.6.2
Prescaled Clock
E
E/2
E/4
E/8
E/16
E/32
E/64
E/128
Counter Control Register (EVCTL)
$1071
7
EVOEN
6
EVPOL
5
EVI2C
4
EVI2B
3
EVI2A
2
EVI1C
1
EVI1B
0
EVI1A
RESET:
0
0
0
0
0
0
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00.
EVCTL
EVOEN — Event Output Enable (Port H, bit 6)
1 – PH6 is used as Event output.
0 – PH6 is used as a general purpose I/O.
EVPOL — Event Output Polarity
1 – Event Output (EVO) will be set (to one) when ECMP1A matches, and cleared (to
zero) when ECMP1B matches.
0 – Event Output (EVO) will be set (to one) when ECMP1B matches, and cleared (to
zero) when ECMP1A matches.
EVI2C, EVI2B, EVI2A — Event Input Select 2 (EVI2)
These three bits determine the function of event Input unit 2 as shown in the following
tables.
The following table applies to modes 1 and 3 only:
EVI2C
EVI2B
EVI2A
PH4
Clock Source
Count Mode
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
I/O
I/O
EVI2
EVI2
EVI2
EVI2
EVI2
EVI2
Scaled E
Scaled E
Scaled E
External
External
E-Clock
E-Clock
Count stop
Count always
Inhibit counting on EVI2 = 0
Inhibit counting on EVI2 = 1
Count on falling edge of EVI2
Count on rising edge of EVI2
Inhibit counting on EVI2 = 0
Inhibit counting on EVI2 = 1
MOTOROLA
11-16
EVENT COUNTER
MC68HC11G5
The following table applies to mode 0 only:
EVI2C
EVI2B
EVI2A
Clear input mode for EVCNT2
0
1
1
1
1
X
0
0
1
1
X
0
1
0
1
Not used
Falling edge of EVI2 (PH4)
Rising edge of EVI2 (PH4)
Logic HIGH (1) level on EVI2
Logic LOW (0) level on EVI2
In mode 0, EVI2 is used as a “clear” input to (EVCNT2).
Note:
In mode 2, these three bits should be reset to zero to allow PH4 to be used as an I/O port.
EVI1C, EVI1B, EVI1A — Event Input Select 1 (EVI1)
These three bits determine the operation of event input unit 1 as shown in the following
table.
The following table applies to modes 0, 1 and 2 only:
EVI1C
EVI1B
EVI1A
PH5
Clock Source
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
X
I/O
I/O
EVI1
EVI1
EVI1
EVI1
EVI1
Scaled E
Scaled E
Scaled E
External
External
External
Note:
11.6.3
Count Mode
Count stop
Count always
Inhibit counting on EVI1 = 0
Inhibit counting on EVI1 = 1
Count on falling edge of EVI1
Count on rising edge of EVI1
Count on both falling and
rising edges of EVI1
In mode 3, these three bits should be reset to zero to allow PH5 to be used as an I/O port.
Counters Enable/Interrupt Mask Register (EVMSK)
7
EVCEN
6
$1072
RESET:
0
0
READ:
Any time.
WRITE:
Any time.
RESET:
$00.
5
0
4
0
3
0
2
0
1
EV2I
0
EV1I
0
0
EVMSK
EVCEN — Event Counters Enable
0 – Event counters EVCNT1 and EVCNT2 are cleared. Also the event output (EVO)
is cleared to a logic low level (when EVPOL = 0 and EVOEN = 1). The EVCLK and
EVCTL registers should be written while this bit is “0”.
1 – Event counters are enabled.
MC68HC11G5
EVENT COUNTER
MOTOROLA
11-17
EV2I — Event 2 Interrupt Enable
0 – Interrupt inhibited.
1 – Hardware interrupt requested when EV2F flag set.
EV1I — Event 1 Interrupt Enable
0 – Interrupt inhibited.
1 – Hardware interrupt requested when EV1F flag set.
11.6.4
Interrupt Flag Register (EVFLG)
7
6
5
4
3
2
$1073
RESET:
0
0
0
0
0
0
1
EV2F
0
EV1F
0
0
EVFLG
READ:
Any time.
WRITE:
Used as clearing mechanism (bits set cause corresponding bits to be cleared).
RESET:
$00.
EV2F — Event Interrupt 2 Flag
Set by a successful match of EVCNT2 and ECMP2B. This bit is cleared automatically by
a write to the EVFLG register with bit 1 set.
EV1F — Event interrupt 1 Flag
Set by a successful match of EVCNT1 and ECMP1A. This bit is cleared automatically by
a write to the EVFLG register with bit 0 set.
11.6.5
Counter Registers (EVCNTx)
$1074
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
EVCNT1
$1075
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
EVCNT2
RESET:
U
U
U
U
U
U
U
U
READ:
Any time.
WRITE:
Forces value to $00.
RESET:
Indeterminate.
MOTOROLA
11-18
EVENT COUNTER
MC68HC11G5
11.6.6
Counter Compare Registers (ECMPx)
$1076
7
BIT7
6
BIT6
5
BIT5
4
BIT4
3
BIT3
2
BIT2
1
BIT1
0
BIT0
ECMP1A
$1077
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
ECMP2A
$1078
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
ECMP1B
$1079
BIT7
BIT6
BIT5
BIT4
BIT3
BIT2
BIT1
BIT0
ECMP2B
RESET:
1
1
1
1
1
1
1
1
READ:
Any time.
WRITE:
Any time.
RESET:
$FF.
Compare registers ECMP1A and ECMP1B are associated with counter EVCNT1. Compare
registers ECMP2A and ECMP2B are associated with counter EVCNT2.
11.7
PWM USING THE EVENT COUNTER
The PWM function of the event counter differs from the main PWM (discussed in Section 10) in that
it has no double buffered duty and period registers. This means that it is possible to generate a cycle
in which there is no duty change of state. This occurs when the duty value written is lower than the
previous value, but the counter is already past the new value. In this case the counter register will
increment all the way to the period count, roll over to $00 and count up to the new duty value before
matching. This situation can be avoided by using the event interrupts to help calculate, in software,
the correct values of duty and period to be written to the compare registers.
11.8
EFFECTIVE RANGE OF THE SET UP VALUES
In mode 0:
ECMP1A and ECMP1B:
ECMP2A and ECMP2B:
0 to 255 ($00 to $FF)
0 to 255 ($00 to $FF)
In modes 1, 2 and 3:
ECMP1A and ECMP1B:
1 to 255 ($01 to $FF)
(These values follow the boundary conditions of the PWM function.)
ECMP2A and ECMP2B:
MC68HC11G5
1 to 255 to 256 ($01 to $FF to $00).
EVENT COUNTER
MOTOROLA
11-19
11.9
BOUNDARY CONDITIONS OF THE PWM FUNCTION
The PWM function (In modes 1, 2, and 3) follows the boundary conditions described below. The
period is determined by the value in the ECMP1A register (8-bit). The duty value is determined by
the values in the ECMP1A and ECMP1B registers (8-bit).
If duty = 0, period > 0, EVPOL = 0 and EVOEN = 1;
PH6 is always high.
If duty = 0, period > 0, EVPOL = 1 and EVOEN = 1;
PH6 is always low.
If duty ≥ period, EVPOL = 0 and EVOEN =1;
PH6 is always low.
If duty ≥ period, EVPOL = 1 and EVOEN =1;
PH6 is always high.
If period = 0, EVPOL = 0 and EVOEN =1;
PH6 is always low.
If period = 0, EVPOL = 1 and EVOEN =1;
PH6 is always high.
If EVOEN = 0;
PH6 is I/O port under the control of
DDRH bit 6.
MOTOROLA
11-20
EVENT COUNTER
MC68HC11G5
SECTION 12
CPU, ADDRESSING MODES AND INSTRUCTION SET
This section discusses the M68HC11 central processing unit (CPU) architecture, its addressing
modes and the instruction set (by instruction type). Everything discussed in this section applies to
the MC68HC11G5. For more detailed information on the instruction set, refer to the M68HC11
Reference Manual (M68HC11RM/D).
12.1
PROGRAMMING MODEL AND CPU REGISTERS
In addition to being able to execute all M6800 and M6801 instructions, the MC68HC11G5 uses a
4-page opcode map to allow execution of 91 new opcodes (see 12.3: INSTRUCTION SET).
Seven registers, shown in Figure 12-1 and discussed in the following paragraphs, are available
to programmers.
7
0
Accumulator A
7
Accumulator B
0
A:B
15
Double Accumulator D
0
D
15
Index Register X
0
IX
15
Index Register Y
0
IY
15
Stack Pointer
0
SP
15
Program Counter
7
0
0
PC
Condition Code Register
S X H
I
N
Z V C
CCR
Carry
Overflow
Zero
Negative
I Interrupt Mask
Half-carry (from bit 3)
X Interrupt Mask
Stop Disable
Figure 12-1. Programming Model
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-1
12.1.1
Accumulators A and B
Accumulator A and accumulator B are general purpose 8-bit registers used to hold operands and
results of arithmetic calculations or data manipulations. These two accumulators can be concatenated
into a single 16-bit accumulator called accumulator D.
12.1.2
Index Register X (IX)
The 16-bit IX register is used for indexed mode addressing. It provides a 16-bit indexing value which
is added to an 8-bit offset provided in an instruction to create an effective address. The IX register
can also be used as a counter or as a temporary storage register.
12.1.3
Index Register Y (IY)
The 16-bit IY register is also used for indexed mode addressing, similar to the IX register;
however, all instructions using the IY register have a 2-byte opcode and require an extra cycle of
execution time.
12.1.4
Stack Pointer (SP)
The stack pointer (SP) is a 16-bit register which contains the address of the next free location on
the stack. The stack is configured as a sequence of last-in/first-out read/write registers which allow
important data to be stored during interrupts and subroutine calls. Each time a new byte is added
to the stack (a push), the SP is decremented; each time a byte is removed from the stack (a pull)
the SP is incremented.
12.1.5
Program Counter (PC)
The program counter is a 16-bit register which contains the address of the next instruction to
be executed.
12.1.6
Condition Code Register (CCR)
The condition code register is an 8-bit register in which the bits signify the results of the instruction
just executed. These bits can be individually tested by software and a specific action can be taken
as a result of the test. Each individual condition code register bit is explained below.
Carry/Borrow (C) — The C bit is set if there was a carry or borrow out of the arithmetic logic unit (ALU)
during the last arithmetic operation. The C bit is also affected during shift and rotate instructions.
Overflow (V) — The overflow bit is set if there was an arithmetic overflow as a result of the operation;
otherwise, the V bit is cleared.
Zero (Z) — The zero bit is set if the result of the last arithmetic, logic or data manipulation operation
was zero; otherwise, the Z bit is cleared.
MOTOROLA
12-2
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
Negative (N) — The negative bit is set if the result of the last arithmetic, logic or data manipulation
operation was negative; otherwise, the N bit is cleared. A result is said to be negative if its most
significant bit is set to one.
I Interrupt Mask (I) — The I interrupt mask bit is set, either by hardware or software, to disable (mask)
all maskable interrupt sources (both external and internal).
Half Carry (H) — The half carry bit is set when a carry occurs between bits 3 and 4 of the ALU during
an ADD, ABA or ADC instruction; otherwise, the H bit is cleared.
X Interrupt Mask (X) — The X interrupt mask bit is set only by hardware (RESET or XIRQ
acknowledge) and is cleared only by a software instruction (TAP or RTI).
Stop Disable (S) — The stop disable bit is set to disable the STOP instruction, and cleared to enable
the STOP instruction. The S bit is program controlled. The STOP instruction is treated as no
operation (NOP) if the S bit is set.
12.2
ADDRESSING MODES
In the M68HC11 CPU, six addressing modes can be used to reference memory; immediate, direct,
extended, indexed (with either of two 16-bit index registers and an 8-bit offset), inherent, and
relative. Some instructions require an additional byte before the opcode to accommodate a multipage opcode map; this byte is called a pre-byte.
The following paragraphs provide a description of each addressing mode. In these descriptions the
term “effective address” is used to indicate the memory address from which the argument is fetched
or stored, or from which execution is to proceed.
12.2.1
Immediate Addressing (IMM)
In the immediate addressing mode, the actual argument is contained in the byte(s) immediately
following the instruction, where the number of bytes matches the size of the register. These are two,
three, or four (if pre-byte is required) byte instructions.
12.2.2
Direct Addressing (DIR)
In the direct addressing mode (sometimes called page zero addressing), the least significant byte
of the operand address is contained in a single byte following the opcode. The high order byte of
the effective address is assumed to be $00 and is not included as an instruction byte. Direct
addressing allows the user to access $0000 through $00FF using 2-byte instructions and execution
time is reduced by eliminating the additional memory access. In most applications, this 256-byte
area is reserved for frequently referenced data. In the MC68HC11G5, software can configure
the memory map so that internal RAM, and/or internal registers or external memory can occupy
these addresses.
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-3
12.2.3
Extended Addressing (EXT)
In the extended addressing mode, the effective address of the instruction appears explicitly in the
two bytes following the opcode. Therefore, the length of most instructions using the extended
addressing mode is three bytes: one for the opcode and two for the effective address.
12.2.4
Indexed Addressing (IND, X; IND, Y)
In the indexed addressing mode, either the X or Y index register is used in calculating the effective
address. In this case, the effective address is variable and depends on the current contents of the
X or Y index register and a fixed 8-bit unsigned offset contained in the instruction. This addressing
mode can be used to reference any memory location in the 64 kbyte address space. These are
usually two (or three if a pre-byte is required) byte instructions, the opcode plus the 8-bit offset.
12.2.5
Inherent Addressing (INH)
In the inherent addressing mode, all of the information is contained in the opcode. The operands
(if any) are registers and no memory reference is required. These are usually one or two
byte instructions.
12.2.6
Relative Addressing (REL)
The relative addressing mode is used for branch instructions. If the branch condition is true, the
contents of the 8-bit signed byte following the opcode (the offset) is added to the contents of the
program counter to form the effective branch address; otherwise, control proceeds to the instruction
immediately following the branch instruction. These are usually two byte instructions.
12.3
INSTRUCTION SET
This section explains the basic capabilities and organization of the instruction set. For this
discussion the instruction set is divided into functional groups of instructions. Some instructions will
appear in more than one functional group. For example, transfer accumulator A to condition code
register (TAP) appears in the condition-code-register group and in the load/store/transfer subgroup
of accumulator/memory instructions. For a detailed explanation of each instruction refer to the
M68HC11 Reference Manual (M68HC11RM/D).
In order to expand the number of instructions used in the MC68HC11G5, a pre-byte mechanism has
been added which affects certain instructions. Most of the instructions affected are associated with
the Y index register. Instructions which do not require a pre-byte are said to reside in page 1 of the
opcode map. Instructions requiring a pre-byte are said to reside in pages 2, 3, and 4 of the opcode
map. The opcode map pre-byte codes are $18 for page 2, $1A for page 3, and $CD for page 4. A
pre-byte code applies only to the opcode which immediately follows it. That is, all instructions are
assumed to be single byte opcodes unless the first byte of the instruction happens to correspond
to one of the three pre-byte codes rather than a page 1 opcode.
MOTOROLA
12-4
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
12.3.1
Accumulator and Memory Instructions
Most of these instructions use two operands. One operand is either an accumulator or an index
register while the second operand is usually obtained from memory using one of the addressing
modes discussed earlier. These accumulator memory instructions can be divided into six subgroups:
1.
2.
3.
4.
5.
6.
Loads, stores and transfers,
Arithmetic operations,
Multiply and divide,
Logical operations,
Data testing and bit manipulation,
Shifts and rotates.
These instructions are discussed in the following tables and paragraphs.
12.3.1.1
Loads, Stores and Transfers
Almost all MCU activities involve moving data from memories or peripherals into the CPU or moving
results from the CPU to memory or to I/O devices. The load, store, and transfer instructions
associated with the accumulators are summarized in the following table. There are additional load,
store, push, and pull instructions associated with the index registers and stack pointer register
(see 12.3.2 Stack And Index Register Instructions).
Table 12-1. Loads, Stores and Transfers
Function
Mnemonic
Clear Memory Byte
IMM
DIR
CLR
EXT
INDX
INDY
X
X
X
INH
Clear Accumulator A
CLRA
X
Clear Accumulator B
CLRB
X
Load Accumulator A
LDAA
X
X
X
X
X
Load Accumulator B
LDAB
X
X
X
X
X
LDD
X
X
X
X
X
Load Double Accumulator D
Pull A from Stack
PULA
X
Pull B from Stack
PULB
X
Push A onto Stack
PSHA
X
Push B onto Stack
PSHB
Store Accumulator A
STAA
Store Accumulator B
X
X
X
X
X
X
STAB
X
X
X
X
X
Store Double Accumulator D
STD
X
X
X
X
X
Transfer A to B
TAB
X
Transfer A to CCR
TAP
X
Transfer B to A
TBA
X
Transfer CCR to A
TPA
X
Exchange D with X
XGDX
X
Exchange D with Y
XGDY
X
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-5
12.3.1.2
Arithmetic Operations
This group of instructions supports arithmetic operations on a variety of operands. 8 and 16-bit
operations are supported directly and can easily be extended to support multiple word operands.
Twos complement (signed) and binary (unsigned) operations are supported directly. BCD arithmetic
is supported by following normal arithmetic instruction sequences with the decimal adjust accumulator
A (DAA) instruction to restore results to BCD format. Compare instructions perform a subtraction
within the CPU to update the condition code bits without altering either operand. Test instructions
are provided but are seldom needed since almost all other operations automatically update the
condition code bits anyway.
Table 12-2. Arithmetic Operations
Function
Mnemonic
IMM
DIR
EXT
INDX
INDY
INH
Add Accumulators
ABA
X
Add Accumulator B to X
ABX
X
Add Accumulator B to Y
ABY
X
Add with Carry to A
ADCA
X
X
X
X
X
Add with Carry to B
ADCB
X
X
X
X
X
Add Memory to A
ADDA
X
X
X
X
X
Add Memory to B
ADDB
X
X
X
X
X
Add Memory to D (16-bit
ADDD
X
X
X
X
X
X
X
X
X
X
Compare A to B
CBA
Compare A to Memory
CMPA
Compare B to Memory
X
CMPB
X
X
X
X
X
Compare D to Memory (16-bit
CPD
X
X
X
X
X
Decimal Adjust A (for BCD
DAA
Decrement Memory Byte
DEC
X
X
X
Decrement Accumulator A
DECA
Decrement Accumulator B
DECB
Increment Memory Byte
X
X
X
INC
Increment Accumulator A
INCA
Increment Accumulator B
INCB
Twos Complement Memory Byte
NEG
X
X
X
X
X
X
X
X
Twos Complement Accumulator A
NEGA
Twos Complement Accumulator B
NEGB
Subtract with Carry from A
SBCA
X
X
X
X
X
Subtract with Carry from B
SBCB
X
X
X
X
X
Subtract Memory from A
SUBA
X
X
X
X
X
Subtract Memory From B
SUBB
X
X
X
X
X
Subtract Memory From D (16-bit
SUBD
X
X
X
X
X
X
X
X
Test Memory for Zero or Minus
TST
X
X
Test A for Zero or Minus
TSTA
X
Test B for Zero or Minus
TSTB
X
MOTOROLA
12-6
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
12.3.1.3
Multiply and Divide
One multiply and two divide instructions are provided. The 8-bit by 8-bit multiply instruction (MUL)
produces a 16-bit result. The integer divide (IDIV) performs a 16-bit by 16-bit divide and produces
a 16-bit result and a 16-bit remainder. The fractional divide (FDIV) divides a 16-bit numerator by a
larger 16-bit denominator to produce a 16-bit result (a binary weighted fraction between 0 and
0.99998) and a 16-bit remainder. FDIV can be used to further resolve the remainder from an IDIV
or FDIV operation.
Table 12-3. Multiply and Divide
Function
Multiply (A x B
INH
MUL
X
FDIV
X
IDIV
X
D)
Fractional Divide (D ÷ X
Integer Divide (D ÷ X
12.3.1.4
Mnemonic
X; r
X; r
D)
D)
Logical Operations
This group of instructions is used to perform the boolean logical operations AND, inclusive-OR,
exclusive-OR, and complement.
Table 12-4. Logical Operations
Function
Mnemonic
IMM
DIR
EXT
INDX
INDY
AND A with Memory
ANDA
X
X
X
X
X
AND B with Memory
ANDB
X
X
X
X
X
Bit(s) Test A with Memory
BITA
X
X
X
X
X
Bit(s) Test B with Memory
BITB
X
X
X
X
X
X
X
X
Ones Complement Memory Byte
COM
INH
Ones Complement A
COMA
X
Ones Complement B
COMB
X
OR A with Memory (Exclusive
EORA
X
X
X
X
X
OR B with Memory (Exclusive
EORB
X
X
X
X
X
OR A with Memory (Inclusive)
ORAA
X
X
X
X
X
OR B with Memory (Inclusive)
ORAB
X
X
X
X
X
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-7
12.3.1.5
Data Testing and Bit Manipulation
This group of instructions is used to operate on operands as small as a single bit, but these
instructions can also operate on any combination of bits within any 8-bit location in the 64 kbyte
memory space. The bit test (BITA or BITB) instructions perform an AND operation within the CPU
to update condition code bits without altering either operand. The BSET and BCLR instructions read
the operand, manipulate selected bits within the operand, and write the result back to the operand
address. Some care is required when read-modify-write instructions such as BSET and BCLR are
used on I/O and control register locations because the physical location read is not always the same
as the location written.
Table 12-5. Data Testing and Bit Manipulation
Function
Mnemonic
IMM
DIR
EXT
INDX
INDY
Bit(s) Test A with Memory
BITA
X
X
X
X
X
Bit(s) Test B with Memory
BITB
X
X
X
X
X
Clear Bit(s) in Memory
BCLR
X
X
X
Set Bit(s) in Memory
BSET
X
X
X
Branch if Bit(s) Clea
BRCLR
X
X
X
Branch if Bit(s) Se
BRSET
X
X
X
MOTOROLA
12-8
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
12.3.1.6
Shifts and Rotates
The shift and rotate functions in the M68HC11 CPU all involve the carry bit in the condition code
register in addition to the 8 or 16-bit operand in the instruction. This permits easy extension to
multiple word operands. Also, by setting or clearing the carry bit before a shift or rotate instruction,
the programmer can easily control what will be shifted into the opened end of an operand. The ASR
instruction maintains the original value of the most significant bit of the operand which facilitates
manipulation of twos complement (signed) numbers.
Table 12-6. Shifts and Rotates
Function
Mnemonic
Arithmetic Shift Left Memory
ASL
IMM
DIR
EXT
INDX
INDY
X
X
X
INH
Arithmetic Shift Left A
ASLA
X
Arithmetic Shift Left B
ASLB
X
Arithmetic Shift Left Double
ASLD
X
Arithmetic Shift Right Memory
ASR
X
X
X
Arithmetic Shift Right A
ASRA
X
Arithmetic Shift Right B
ASRB
X
(Logical Shift Left Memory)
(LSL)
X
X
X
(Logical Shift Left A
(LSLA)
X
(Logical Shift Left B
(LSLB)
X
(Logical Shift Left Double
(LSLD)
X
Logical Shift Right Memory
LSR
X
X
X
Logical Shift Right A
LSRA
X
Logical Shift Right B
LSRB
X
Logical Shift Right D
LSRD
X
Rotate Left Memory
ROL
X
X
X
Rotate Left A
ROLA
X
Rotate Left B
ROLB
X
Rotate Right Memory
ROR
X
X
X
Rotate Right A
RORA
X
Rotate Right B
RORB
X
The logical left shift instructions are shown in parenthesis because there is no difference between
an arithmetic and a logical left shift. Both mnemonics are recognized by the assembler as equivalent,
but having both instruction mnemonics makes some programs easier to read.
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-9
12.3.2
Stack and Index Register Instructions
The following table summarizes the instructions available for the 16-bit index registers (X and Y)
and the 16-bit stack pointer.
Table 12-7. Stack And Index Register Instructions
Function
Mnemonic
IMM
DIR
EXT
INDX
INDY
INH
Add Accumulator B to X
ABX
X
Add Accumulator B to Y
ABY
X
Compare X to Memory (16 Bit)
CPX
X
X
X
X
X
Compare Y to Memory (16 Bit)
CPY
X
X
X
X
X
Decrement Stack Pointer
DES
X
Decrement Index Register X
DEX
X
Decrement Index Register Y
DEY
X
Increment Stack Pointer
INS
X
Increment Index Register X
INX
X
Increment Index Register Y
INY
X
Load Index Register X
LDX
X
X
X
X
X
Load Index Register Y
LDY
X
X
X
X
X
Load Stack Pointer
LDS
X
X
X
X
X
Pull X from Stack
PULX
X
Pull Y from Stack
PULY
X
Push X onto Stack
PSHX
X
Push Y onto Stack
PSHY
X
Store Index Register X
STX
X
X
X
X
X
Store Index Register Y
STY
X
X
X
X
X
Store Stack Pointer
STS
X
X
X
X
X
Transfer SP to X
TSX
X
Transfer SP to Y
TSY
X
Transfer X to SP
TXS
X
Transfer Y to SP
TYS
X
Exchange D with X
XGDX
X
Exchange D with Y
XGDY
X
The exchange D with X (XGDX) and exchange D with Y (XGDY) instructions provide a simple way
of getting a pointer value from a 16-bit index register to the D accumulator which has more powerful
16-bit arithmetic capabilities than the 16-bit index registers. Since these are bidirectional exchanges,
MOTOROLA
12-10
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
the original value of the D accumulator is automatically preserved in the index register while
the pointer is being manipulated in the D accumulator. When pointer calculations are finished,
another exchange simultaneously updates the index register and restores the D accumulator to its
former value.
The transfers between an index register and the stack pointer deserve additional comment. The
stack pointer always points at the next free location on the stack as opposed to the last thing that
was pushed onto the stack. The usual reason for transferring the stack pointer value into an index
register is to allow indexed addressing access to information that was formerly pushed onto the
stack. In such cases, the address pointed-to by the stack pointer is of no value since nothing has
been stored at that location yet. This explains why the value in the stack pointer is incremented
during transfers to an index register. There is a corresponding decrement of a 16-bit value as it is
transferred from an index register to the stack pointer.
12.3.3
Condition Code Register Instructions
This group of instructions allows the programmer to manipulate bits in the condition code register.
Table 12-8. Condition Code Register Instructions
Function
Mnemonic
INH
Clear Carry Bi
CLC
X
Clear Interrupt Mask Bit
CLI
X
Clear Overflow Bit
CLV
X
Set Carry Bit
SEC
X
Set Interrupt Mask Bit
SEI
X
Set Overflow Bit
SEV
X
Transfer A to CCR
TAP
X
Transfer CCR to A
TPA
X
At first look, it may appear that there should be a set and a clear instruction for each of the 8 bits
in the condition code register while these instructions are present for only 3 of the 8 bits (C, I
and V). Upon closer consideration there are good reasons for not including the set and clear
instructions for the other five bits.
The stop disable (S) bit is an unusual case because this bit is intended to lock out the STOP
instruction for those who view it as an undesirable function in their application. Providing set and
clear instructions for this bit would make it easier to enable STOP when it was not wanted or disable
STOP when it was wanted. The TAP instruction provides a way to change S but cuts the chances
of an undesirable change to S in half because the value of the A accumulator at the time the TAP
instruction is executed determines whether or not S will actually change.
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-11
The XIRQ interrupt mask (X) bit is another unusual case. The definition of this bit specifically states
that software shall not be allowed to change X from 0 to 1, in fact, this is even prohibited by hardware
logic. This immediately eliminates a need for a set X instruction. For arguments similar to those used
for the S bit, the TAP instruction is preferred over a clear X instruction as a means of clearing X
because TAP makes it a little less likely that X will become cleared before the programmer really
intended to clear it.
The half-carry (H) bit needs no set or clear instructions because this condition code bit is only used
by the DAA instruction to adjust the result of a BCD add or subtract. The H bit is not used as a test
condition for any branches so it would not be useful to be able to set or clear this bit.
This leaves only the negative (N) and zero (Z) condition code bits. In contrast to S, X, and H, it is
often useful to be able to easily set or clear these flag bits. A clear accumulator instruction such as
CLRB will clear both the N and Z condition code bits. The instruction “LDAA #$80” causes both N
and Z to be set. Since there are so many simple instructions that can accomplish setting or clearing
of N and Z, it is not necessary to provide specific set and clear instructions for N and Z in this group.
12.3.4
Program Control Instructions
This group of instructions is used to control the flow of a program rather than to manipulate data.
Since this group is so large it has been further divided into five subgroups:
1.
2.
3.
4.
5.
12.3.4.1
Branches,
Jumps,
Subroutine calls and returns,
Interrupt handling,
Miscellaneous.
Branches
These instructions allow the CPU to make decisions based on the contents of the condition code
bits. All decision blocks in a flow chart would correspond to one of the conditional branch instructions
which are summarized in the following table.
MOTOROLA
12-12
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
Table 12-9. Branches
Function
Mnemonic
REL
DIR
INDX
INDY
Comments
Branch if Carry Clea
BCC
X
C=0?
Branch if Carry Set
BCS
X
C=1?
Branch if Equal Zero
BEQ
X
Z=1?
Branch if Greater Than or Equa
BGE
X
Signed ≥
Branch if Greater Than
BGT
X
Signed >
Branch if Higher
BHI
X
Unsigned >
Branch if Higher or Same (same as BCC)
BHS
X
Unsigned ≥
Branch if Less Than or Equa
BLE
X
Signed ≤
Branch if Lower (same as BCS)
BLO
X
Unsigned <
Branch if Lower or Same
BLS
X
Unsigned ≤
Branch if Less Than
BLT
X
Signed <
Branch if Minus
BMI
X
N=1?
Branch if Not Equal
BNE
X
Z=0?
Branch if Plus
BPL
X
N=0?
Branch if Bit(s) Clear in Memory Byte
BRCLR
Branch Never
BRN
Branch if Bit(s) Set in Memory Byte
X
X
X
X
BRSET
Bit Manipulation
3-cycle NOP
X
X
X
Bit Manipulation
Branch if Overflow Clear
BVC
X
V=0?
Branch if Overflow Set
BVS
X
V=1?
The limited range of branches (-128/+127 locations) is more than adequate for most (but not all)
situations. In cases where this range is too short, a jump instruction must be used. For every branch
there is a branch for the opposite condition so it is a simple matter to replace a branch which has
an out-of-range destination with a sequence consisting of the opposite branch around a jump to the
out-of-range destination. For example, if a program contained the instruction...
BHI
TINBUK2
Unsigned >
where TINBUK2 was out of the -128/+127 location range, the following instruction sequence could
be substituted...
AROUND
MC68HC11G5
BLS
AROUND
Unsigned ≤
JMP
TINBUK2
Still go to TINBUK2 if >
EQU
*
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-13
12.3.4.2
Jumps
The jump instruction allows control to be passed to any address in the 64 kbyte memory map.
Table 12-10. Jumps
Function
Mnemonic
DIR
EXT
INDX
INDY
JMP
X
X
X
X
Jump
12.3.4.3
INH
Subroutine Calls and Returns (BSR, JSR, RTS)
These instructions provide an easy way to break a programming task into manageable blocks called
subroutines. The CPU automates the process of remembering the address in the main program
where processing should resume after the subroutine is finished. This address is automatically
pushed onto the stack when the subroutine is called and is pulled off the stack during the return from
subroutine (RTS) instruction which ends the subroutine.
Table 12-11. Subroutine Calls and Returns (BSR, JSR, RTS)
Mnemonic
REL
Branch to Subroutine
Function
BSR
X
Jump to Subroutine
JSR
Return from Subroutine
RTS
12.3.4.4
DIR
EXT
INDX
INDY
X
X
X
X
INH
X
Interrupt Handling (RTI, SWI, WAI)
This group of instructions is related to interrupt operations.
Table 12-12. Interrupt Handling (RTI, SWI, WAI)
Function
Mnemonic
INH
Return from Interrupt
RTI
X
Software Interrupt
SWI
X
Wait for Interrupt
WAI
X
The software interrupt (SWI) instruction is similar to a jump to subroutine (JSR) instruction except
that the contents of all working CPU registers are saved on the stack, rather than just saving the
return address. SWI is unusual in that it is requested by the software program as opposed to other
interrupts which are requested asynchronously with respect to the executing program.
MOTOROLA
12-14
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
Wait for interrupt (WAI) has two main purposes. WAI is executed to place the MCU in a reduced
power consumption standby state (WAIT mode) until some interrupt occurs. The other use is to
reduce the latency time to some important interrupt. The reduction of latency comes about
because the time consuming task of storing the CPU registers on the stack is done as soon as
the WAI instruction starts to execute. When the interrupt finally comes, the CPU is ready to
fetch the appropriate vector so the delay associated with register stacking is eliminated from latency
calculations.
12.3.4.5
Miscellaneous (NOP, STOP, TEST)
NOP can be used to introduce a small time delay into the flow of a program. This is often useful in
meeting the timing requirements of slow peripherals. By incorporating NOP instructions into loops,
longer delays can be produced.
Table 12-13. Miscellaneous (NOP, STOP, TEST)
Function
Mnemonic
INH
NOP
X
Stop Clocks
STOP
X
Test
TEST
X
No Operation (2-cycle delay
During debugging it is common to replace various instructions with NOP opcodes to effectively
remove an unwanted instruction without having to rearrange the rest of the program.
Occasionally a programmer is faced with the problem of fine tuning the delays through various paths
in his program. In such cases it is sometimes useful to use a BRN instruction as a 3 cycle NOP. It
is also possible to fine tune execution time by choosing alternate addressing mode variations of
instructions to change the execution time of an instruction sequence without changing the program’s
function.
STOP causes the oscillator and all MCU clocks to freeze. This frozen state is called STOP mode
and power consumption is dramatically reduced in this mode. The operation of this instruction is also
dependent upon the S condition code bit because the STOP mode is not appropriate for all
applications. If S is 1 the STOP instruction is treated as a no operation (NOP) instruction and
processing just continues to the next instruction.
The TEST instruction is used only during factory testing and is treated as an illegal opcode in normal
operating modes of the MCU. This instruction causes unusual behaviour on the address bus (counts
backwards) which prevents its use in any normal system.
MC68HC11G5
CPU, ADDRESSING MODES AND INSTRUCTION SET
MOTOROLA
12-15
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MOTOROLA
12-16
CPU, ADDRESSING MODES AND INSTRUCTION SET
MC68HC11G5
SECTION 13
ELECTRICAL SPECIFICATIONS
This section contains the electrical specifications and associated timing information for the
MC68HC11G5.
13.1
MAXIMUM RATINGS †
Rating
Symbol
Supply Voltage
Value
Unit
VDD
– 0.5 to 7.0
V
Input Voltage
Vin
VSS – 0.5 to
VDD + 0.5
V
Operating Temperature Range
TA
TL to TH
– 40 to 85
°C
Tstg
– 65 to 150
°C
Storage Temperature Range
Current Drain per Pin *
Excluding VDD and VSS
ID
25
mA
* One pin at a time, observing maximum power dissipation limits.
† This device contains protective circuitry against damage due to
high static voltages or electrical fields; however, it is advised that
normal precautions be taken to avoid application of any voltages
higher than maximum-rated voltages to this high-impedance
circuit. Reliability of operation is enhanced if unused inputs are
tied to an appropriate logic voltage level (eg. either GND or VDD ).
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-1
13.2
THERMAL CHARACTERISTICS
Characteristic
Thermal Resistance Plastic
13.3
Symbol
Value
Unit
θ JA
50
°C/W
POWER CONSIDERATIONS
The average chip junction temperature, TJ, in degrees Celsius can be obtained from the following
equation:
TJ= TA + (PD • θJA )
(1)
Where:
TA
θJA
PD
PINT
PI/O
=
=
=
=
=
Ambient temperature (oC)
Package thermal resistance, junction-to-ambient (oC/W)
PINT + PI/O
Internal chip power = IDD x VDD (W)
Power dissipation on input and output pins (W) — user determined)
Note: For most applications PI/O < PINT and can be neglected.
An approximate relationship between PD and TJ (if PI/O is neglected) is:
PD= K ÷ (TJ + 273oC)
(2)
Solving equations (1) and (2) for K gives:
K = PD • (TA+ 273oC) + θJA • PD2
(3)
Where K is a constant pertaining to the particular part. K can be determined from equation (3) by
measuring PD (at equilibrium) for known TA. Using this value of K, the values of PD and TJ can be
obtained by solving equations (1) and (2) for any value of TA.
MOTOROLA
13-2
ELECTRICAL SPECIFICATIONS
MC68HC11G5
13.4
DC ELECTRICAL CHARACTERISTICS
(VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH unless otherwise noted)
Symbol
Min
Max
Unit
VOL
VOH
—
VDD - 0.1
0.1
—
V
All outputs except
RESET, XTAL and MODA
VOH
VDD - 0.8
—
V
Output Low Voltage
I Load = 1.6mA
All outputs except XTAL
VOL
—
0.4
V
Input High Voltage
RESET
All inputs except RESET
VIH
VIH
0.8 x VDD
0.7 x VDD
VDD
VDD
V
Input Low Voltage
I Load = 1.6mA
All Inputs
VIL
—
0.8
V
PA0-7, PC0-7, PD0-5, PG0-7,
I OZ
—
±10
µA
I in
—
±1.0
µA
Characteristic
Output Voltage
I Load = ± 10.0µA (See Note 1)
All outputs
All outputs except RESET and MODA
Output High Voltage
I Load = - 0.8mA, VDD = 4.5V (See Note 1)
I/O Ports, Three-state Leakage
PH0-7, PJ0-3, MODA/ LIR, RESET
Vin = VIH or V IL
All Inputs
Input Current
Vin = VDD or VSS
RAM Standby Voltage
Powerdown
VSB
2.0
VDD
V
RAM Standby Current
Powerdown
I SB
—
20
µA
I DD (run)
—
30
mA
I DD (wait)
—
15
mA
—
100
µA
—
12
12
pF
pF
Total Supply Current (See Note 2)
RUN:
Single-Chip Mode
WAIT: (All Peripheral Functions Shut Down)
Single-Chip Mode
STOP: (No Clocks)
Single-Chip Mode
Input Capacitance
I DD
I DD (stop)
IRQ, XIRQ, EXTAL
MODA/ LIR, RESET, all Ports except Port E
Cin
Cin
—
NOTES:
1. VOH specification for RESET and MODA is not applicable because they are opendrain pins.
VOH specification is not applicable to ports C and D in wired-OR mode.
2. All ports configured as inputs,
VIL ≤ 0.2V,
VIL ≥ VDD - 0.2V,
No dc loads,
EXTAL is driven with a square wave, and
t cyc = 476.5ns.
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-3
VDD
Equivalent Test Load 1
R2
Pins
PA0-7, PB0-7, PC0-7, PD0, PD5,
PF0-7, PG0-7, PH0-7, PJ0-3, E, R/W
PD1-PD4
Test
Point
C1
R1
V DD
R1
3.26kΩ
R2
2.38kΩ
C1
90pF
3.26kΩ
2.38kΩ
200pF
V DD – 0.8V
Clocks
0.4V
V SS
0.4V
Nom.
Nom.
— 70% of VDD
Inputs
— 20% of VDD
Nominal Timing
Outputs
V DD
V DD – 0.8V
0.4V
V SS
D.C. Testing
V DD
Clocks
70% of VDD
20% of VDD
V SS
20% of VDD
Spec
70% of VDD
20% of VDD
Inputs
Spec
(See Note 2)
— VDD – 0.8V
— 0.4V
Spec Timing
Outputs
V DD
V SS
A.C. Testing
Notes:
70% of VDD
20% of VDD
1. Full test loads are applied during all DC electrical tests and AC timing measurements.
2. During AC timing measurements, inputs are driven to 0.4 volts and VDD – 0.8
volts while timing measurements are taken at the 20% and 70% of VDD points.
Figure 13-1. Test Methods
MOTOROLA
13-4
ELECTRICAL SPECIFICATIONS
MC68HC11G5
(mA)
I
DD (mA)
IDD
226
6
224
4
222
2
220
0
118
8
116
6
114
4
112
2
110
0
88
66
44
22
00
5.5V
5.5V
4.5V
4.5V
00
0.5
0.5
11
1.5
1.5
2
2
2.5
2.5
33
3.5
3.5
Bus Frequency
Frequency (MHz)
Bus
(MHz)
IDD (mA)
IDD (mA)
Figure 13-2. Run IDD vs Bus Frequency (Single Chip Mode – 4.5V, 5.5V)
226
6
224
4
222
2
220
0
118
8
116
6
114
4
112
2
110
0
8
8
6
6
4
4
2
2
0
0
5.5V
4.5V
0
0
0.5
11
1.5
1.5
2
2.5
2.5
33
3.5
3.5
Bus
(MHz)
Bus Frequency
Frequency (MHz)
Figure 13-3. Run IDD vs Bus Frequency (Expanded Mode – 4.5V, 5.5V)
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-5
6
IDD (mA)
IDD (mA)
5
5
4
4
3
3
5.5V
2
2
4.5V
1
1
0
0
0
0
0.5
0.5
11
1.5
1.5
22
2.5
2.5
3
3
3.5
3.5
Bus Frequency
(MHz)
Bus
Frequency
(MHz)
Figure 13-4. Wait IDD vs Bus Frequency (Single Chip Mode – 4.5V, 5.5V)
6
5
5
IDD (mA)
IDD (mA)
4
4
3
3
5.5V
2
4.5V
1
0
0
0
0.5
11
1.5
2
2.5
2.5
3
3.5
Bus Frequency
(MHz)
Bus
Frequency
(MHz)
Figure 13-5. Wait IDD vs Bus Frequency (Expanded Mode – 4.5V, 5.5V)
MOTOROLA
13-6
ELECTRICAL SPECIFICATIONS
MC68HC11G5
13.5
CONTROL TIMING
(VDD = 5.0 Vdc ± 10%, V SS = 0 Vdc, TA = TL to TH unless otherwise noted)
Symbol
Min
Max
Unit
f XTAL
4f o
—
DC
8.4
8.4
MHz
MHZ
fo
fo
—
DC
2.1
2.1
MHz
MHZ
t cyc
476
—
ns
t OXOV
—
100
ms
t SRS
t SRS
—
—
4
4064
t cyc
t cyc
Wait Recovery Startup Time
t WRS
—
4
t cyc
Reset Input Pulse Width (See Note 1)
t RLRH
8
1
—
—
2
0
—
—
t cyc
496
—
ns
t ILIL
Note 2
—
t cyc
t PCS
t PCS
t PCS
t TSE
t TSD
69
50
170
—
—
—
—
—
159
65
ns
ns
ns
ns
ns
Characteristic
External Oscillator Frequency
Crystal option
External clock option
Internal Operating Frequency
Crystal (f XTAL /4)
External clock
Cycle Time
All outputs except XTAL
Crystal Oscillator Startup Time
Stop Recovery Startup Time
DLY = 0
DLY = 1
t cyc
(To guarantee external reset vector)
(Minimum input time; may be pre-empted by internal reset)
Mode Programming
Interrupt Pulse Width,
IRQ Edge Sensitive Mode
Setup time
Hold time
t MPS
t MPH
t ILIH = tcyc + 20ns
t ILIH
Interrupt Pulse Period
Processor Control
RESET, WAIT, IRQ
MRDY
HALT
Bus Tri State Enable
Bus Tri State Disable
(tPCS = 1/4 tcyc - 50ns)
(tPCS = 1/4 tcyc + 20ns)
(tTSE = 1/4 tcyc + 40ns)
ns
NOTES:
1.
RESET will be recognised during the first clock cycle it is held low. Internal circuitry then drives
the pin low for four clock cycles, releases the pin, and samples the pin level two cycles later to
determine the source of the interrupt.
2.
The minimum period t ILIL should not be less than the number of cycles it takes to execute the
interrupt service routine plus 21 t cyc .
3.
All timing is shown with respect to 20% V DD and 70% VDD unless otherwise noted.
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-7
VDD
tOXOV
EXTAL
4064 tcyc
E
tPCS
t RLRW
RESET
tMPH
tMPS
MODA, MODB
ADDRESS
FFFE FFFE FFFE
NEW
PC
FFFE FFFE FFFE FFFE FFFE FFFF
NEW
PC
Figure 13-6. POR External RESET Timing Diagram
Internal
Clock
IRQ (Edge)
t ILIH
XIRQ,
IRQ (Level)
t SRS
E
Resume program with instruction which follows the STOP instruction
ADDRESS
(XIRQ (X = 1))
STOP
Address
STOP Address + 1
STOP Address + 1
OPCODE
ADDRESS
(IRQ, XIRQ (X=0))
STOP
Address
STOP Address + 1
STOP Address + 1
+2
SP
SP-8
SP-8
FFF2
(FFF4)
FFF3
(FFF5)
New
PC
Figure 13-7. STOP Recovery Timing Diagram
MOTOROLA
13-8
ELECTRICAL SPECIFICATIONS
MC68HC11G5
E
t PCS
IRQ, XIRQ or
Internal Interrupt
tWRS
WAIT
Addr.
ADDRESS
WAIT
Addr+1
SP
SP-1
SP-2 ....SP-8
SP-8
SP-8
SP-8
SP-8
SP-8
SP-8
Vector
Addr+1
New
PC
Vector
Addr
Vector
Addr+1
New
PC
Vect
MSB
Vect
LSB
Vector
Addr.
R/W
Stack Registers
Figure 13-8. WAIT Recovery from Interrupt Timing Diagram
Last cycle of an instruction
E
tPCS
IRQ (Edge)
t ILIH
IRQ (Level), XIRQ
or Internal Interrupt
ADDRESS
DATA
Next
OPCODE
OPCODE
Next
OP+1
SP
SP-1
SP-2
SP-3
SP-4
SP-5
SP-6
SP-7
SP-8
PCL
PCH
IYL
IYH
IXL
IXH
B
A
CCR
SP-8
OPCODE
R/W
Figure 13-9. Interrupt Timing Diagram
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-9
E
Internal
E
External
tPCS
tPCS
MRDY
ADDRESS
DATA
Figure 13-10. Memory Ready Timing Diagram
LAST INSTRUCTION
OPCODE FETCH
HALT STATE
E
tPCS
LIR
HALT
tTSE
ADDRESS
OPCODE ADDR
OPCODE ADDR
tTSE
DATA
OPCODE
OPCODE
Figure 13-11. Entering HALT
MOTOROLA
13-10
ELECTRICAL SPECIFICATIONS
MC68HC11G5
HALT STATE
EXITING HALT
EXECUTE
E
tPCS
LIR
HALT
OPCODE ADDR + 1
ADDRESS
tTSD
DATA
Figure 13-12. Exiting HALT
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-11
13.6
PERIPHERAL PORT CHARACTERISTICS
(VDD = 5.0 Vdc ± 10%, V SS = 0 Vdc, TA = TL to TH unless otherwise noted)
Characteristic
Symbol
Min
Max
Unit
fo
—
2.1
MHz
t cyc
476
—
ns
(t PDSU = -1/4 t cyc + 93ns)
t PDSU
t PDSU
t PDSU
100
100
– 26
—
—
—
ns
ns
ns
(t PDH = 1/4 t cyc + 130ns)
t PDH
t PDH
t PDH
80
80
249
—
—
—
ns
ns
ns
(t PWD = 1/4 t cyc + 90ns)
t PWD
t PWD
—
—
150
209
ns
ns
Frequency of Operation (E Clock)
E Clock Period
Peripheral Data Setup Time
Port A, C, D, J
Port E
Port G, H
Peripheral Data Hold Time
Port A, C, D, J
Port E
Port G, H
Delay Time, Peripheral Data Write
Port J1, J2, A3, A4, A5, A6, A7
Port B, C, D, F, G, H, A0, A1, A2, J0, J3
NOTES:
1.
All timing is shown with respect to 20% V DD and 70% V DD unless otherwise noted.
E Clock
tPWD
Ports
A3-7, J1-2
tPWD
Ports
B, C, D, F, G, H,
A0-2, J0-3
Figure 13-13. Port Write Timing Diagram
MOTOROLA
13-12
ELECTRICAL SPECIFICATIONS
MC68HC11G5
E Clock
Ports
A, C, D, J
tPDSU
Port E
tPDH
1/4 tcyc
Port G, H
tPDSU
tPDH
tPDSU
tPDH
Figure 13-14. Port Read Timing Diagram
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-13
13.7
TIMER CHARACTERISTICS
(VDD = 5.0 Vdc ± 10%, V SS = 0 Vdc, TA = TL to TH unless otherwise noted)
Characteristic
Timer Pulse Width Input Capture
Pulse Accumulator Input
(PWTIM = t cyc + 20ns)
Symbol
Min
Max
Unit
PWTIM
496
—
ns
Timer Output Compare High Valid
t OCH
—
310
ns
Timer Output Compare Low Valid
t OCL
—
295
ns
Timer Input Capture Response Delay
Min = t cyc + 20ns
Max = 2 t cyc + 220ns
t CAP
496
1172
ns
NOTES:
1.
All timing is shown with respect to 20% V DD and 70% V DD unless otherwise noted.
PA0-PA3/PJ1-PJ21
PA0-PA3/PJ1-PJ2
2
PWTIM
PA71,3
PA7 2,3
Notes:
1. Rising edge sensitive input.
2. Failing edge sensitive input.
3. Maximum pulse accumulator clocking rate is E frequency divided by 2.
Figure 13-15. Timer Inputs Timing Diagram
MOTOROLA
13-14
ELECTRICAL SPECIFICATIONS
MC68HC11G5
E Clock
Value = XXXX
Compare
Register
XXXX - 1
XXXX
XXXX + 1
Counter
tOCH
OC1-OC7
Output
tOCL
OC1-OC7
Output
Figure 13-16. Output Compare Timing Diagram
E Clock
IC1-IC6
IC1-IC6
XXXX - 3
XXXX - 2
XXXX - 1
XXXX
Counter
XXXX
Capture
Register
MIN
TCAP
MAX
(Captured)
Figure 13-17. Input Capture Timing Diagram
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-15
13.8
A/D CONVERTER CHARACTERISTICS
(VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = T L to T H, E = 750kHz to 2.1MHz unless otherwise noted)
Min
Absolute
Max
Unit
Resolution
Characteristic
Number of bits resolved by the A/D
Parameter
10
—
—
Bits
Nonlinearity
Maximum deviation from the ideal A/D transfer
characteristics
—
—
TBD
LSB
Zero Error
Difference between the output of an ideal and an
actual A/D for zero input voltage
—
—
TBD
LSB
Full Scale Error
Difference between the output of an ideal and an
actual A/D for full scale input voltage
—
—
TBD
LSB
Total Unadjusted Error
Maximum sum of Nonlinearity, zero error and
full scale error
—
—
TBD
LSB
Quantization Error
Uncertainty due to converter resolution
—
—
±0.5
LSB
Absolute Accuracy
(See Note 1)
Difference between the actual input voltage and the
full scale weighted equivalent of the binary output
code, all error sources included
—
—
TBD
LSB
Conversion Range
(See Notes 3 and 4)
Analog input voltage range
Vrl
—
Vrh
V
Vrh (See Note 2)
Maximum analog reference voltage
Vrl
—
VDD + 0.1
V
Vrl (See Note 2)
Minimum analog reference voltage
VSS - 0.1
—
Vrh
V
Delta Vr (See Note 2)
Minimum difference between V rh and V rl
0
—
—
V
Conversion Time
Total time to perform a single analog to digital
conversion:
1. E Clock
2. Internal RC Oscillator
—
—
36
—
—
t cyc + 24
t cyc
µs
Monotonicity
Conversion result never decreases with an increase
in input voltage and has no missing codes
Zero Input Reading
(See Note 3)
Conversion result when V in = Vrl
$000
—
—
Hex
Full Scale reading
(See Note 4)
Conversion result when V in = Vrh
—
—
$3FF
Hex
Sample Acquisition Time
Analog Input Acquisition sampling time:
1. E Clock
2. Internal RC Oscillator
—
—
13
—
—
8.7
t cyc
—
35 (Typ)
—
pF
—
—
—
—
100
250
nA
µA
Sample Hold Capacitance Input capacitance during sample PE0-PE7
Input Leakage
Input leakage on A/D pins:
PE0-PE7
Vrl, Vrh
Guaranteed
µs
NOTES:
1. Source impedances greater then 10kΩ will adversely affect accuracy, due mainly to input leakage.
2. Performance verified down to 2.5V Delta V r, but accuracy is tested and guaranteed at Delta V r = 5V ± 10%.
3.
Minimum analog input voltage should not go below V SS - 0.3V.
4.
Maximum analog input voltage should not exceed 1.125V rh.
MOTOROLA
13-16
ELECTRICAL SPECIFICATIONS
MC68HC11G5
13.9
EXPANSION BUS TIMING
(VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH unless otherwise noted)
Num
Characteristic
Symbol
Min
Max
Unit
fo
—
2.1
MHz
Frequency of Operation (E-Clock)
1
Cycle Time
t cyc
476
—
ns
2
Pulse Width E Low (1/2 t cyc - 23ns)
t ELEH
215
—
ns
3
Pulse Width E High (1/2 t cyc - 28ns)
t EHEL
210
—
ns
4
E Rise and Fall Time
t R, t F
—
20
ns
9
Address Hold Time (t AH = 1/8 t cyc - 29.5ns)
(See Note 1(A))
t AH
30
—
ns
12
Address Valid Time to E Rise
t AV
120
—
ns
17
Read Data Setup Time
t DSR
30
—
ns
18
Read Data Hold Time
t DHR
10
—
ns
19
Write Data Delay Time
t DDW
—
80
ns
21
Write Data Hold Time
t DHW
50
—
ns
29
MPU Address Access Time
(t ACCA = tAV + tR + t EHEL - t DSR
t ACCA
320
—
ns
(See Note 1(B))
(See Note 1(A))
NOTES:
1. Input clock with duty cycle other than 50% will affect the bus performance. Timing parameters
affected by the input clock duty cycle are identified by (A) and (B). To re-calculate approximate
bus timing values, substitute the following expressions in place of 1/8 t cyc in the above formulae
where applicable:
(A)
(B)
(1-DC) x 1/4 t cyc
DC x 1/4 t cyc
where DC is the decimal value of duty cycle percentage (High time).
2. All timing is shown with respect to 20% V DD and 70% V DD.
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-17
1
2
3
E-Clock
4
4
12
4
9
R/W
Address
29
17
18
Data (Read)
19
21
Data (Write)
Figure 13-18. Non-multiplexed Expanded Bus
MOTOROLA
13-18
ELECTRICAL SPECIFICATIONS
MC68HC11G5
13.10 SERIAL PERIPHERAL INTERFACE (SPI) TIMING
(VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH unless otherwise noted)
Num
Characteristic
Symbol
Min
Max
Unit
Operating Frequency
Master
Slave
f op(m)
f op(s)
dc
dc
0.5
2.1
fo
MHz
1
Cycle Time
Master
Slave
t cyc(m)
t cyc(s)
2.0
480
—
—
t cyc
2
Enable Lead Time
Master
Slave
t lead(m)
t lead(s)
*
240
—
—
ns
ns
3
Enable Lag Time
Master
Slave
t lag(m)
t lag(s)
*
240
—
—
ns
ns
4
Clock (SCK) High Time
Master t w(SCKH)m
Slave t w(SCKH)s
340
190
—
—
ns
ns
5
Clock (SCK) Low Time
Master t w(SCKL)m
Slave t w(SCKL)s
340
190
—
—
ns
ns
6
Data Setup Time
Master
Slave
t su(m)
t su(s)
100
100
—
—
ns
ns
7
Data Hold Time
Master
Slave
t h(m)
t h(s)
100
100
—
—
ns
ns
8
Access Time
(Time to Data Active from High-Impedance State)
Slave
ta
0
120
ns
9
Disable Time
(Hold Time to High-Impedance State)
Slave
ns
t dis
—
240
ns
Data Valid (After Enable Edge)**
t v(s)
—
240
ns
11
Data Hold Time (Outputs) (After Enable Edge)
t ho
- 40
—
ns
12
Rise Time (20% V DD to 70% VDD, C L = 200pF)
SPI Outputs (SCK, MOSI, MISO)
SPI Inputs (SCK, MOSI, MISO, SS)
t r(m)
t r(s)
—
—
100
2.0
ns
µs
Fall Time (70% V DD to 20% VDD, C L = 200pF)
SPI Outputs (SCK, MOSI, MISO)
SPI Inputs (SCK, MOSI, MISO, SS)
t f(m)
t f(s)
—
—
100
2.0
ns
µs
10
13
NOTES:
*
Signal production depends on software.
** Assumes 200 pF load on all SPI pins.
1. All timing is shown with respect to 20% V DD and 70% V DD unless otherwise noted.
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-19
SS
SS is held high on Master
1
SCK
(CPOL=0)
13
12
See
Note
4
5
5
4
SCK
(CPOL=1)
See
Note
6
MISO
(Input)
12
7
13
MSB
LSB
10
MOSI
(Output)
MSB
11
LSB
13
12
Note: This first edge is generated internally but is not seen at the SCK pin.
Figure 13-19. SPI Master Timing (CPHA = 0)
SS
SS is held high on Master
1
13
12
SCK
(CPOL=0)
See
Note
4
5
5
4
SCK
(CPOL=1)
See
Note
6
MISO
(Input)
7
12
13
MSB
LSB
11
MOSI
(Output)
10
MSB
LSB
13
12
Note: This last edge is generated internally but is not seen at the SCK pin.
Figure 13-20. SPI Master Timing (CPHA = 1)
MOTOROLA
13-20
ELECTRICAL SPECIFICATIONS
MC68HC11G5
SS
1
13
12
3
SCK
(CPOL=0)
5
4
2
SCK
(CPOL=1)
8
10
MISO
(Output)
12
4
5
13
11
MSB
6
9
LSB
See Note
7
MOSI
(Input)
MSB
LSB
Note: Not defined but normally MSB of character just received.
Figure 13-21. SPI Slave Timing (CPHA = 0)
SS
1
13
12
SCK
(CPOL=0)
5
4
2
4
5
3
SCK
(CPOL=1)
8
11
MISO
(Output)
13
10
MSB
See Note
MOSI
(Input)
12
6
9
LSB
7
MSB
LSB
Note: Not defined but normally LSB of character previously transmitted.
Figure 13-22. SPI Slave Timing (CPHA = 1)
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-21
13.11 EVENT COUNTER CHARACTERISTICS
Table 13.1. Clock Input (Required Limit)
Clock Input (Required Limit)
Num
1
Characteristic
Symbol
Min
Max
Unit
Cycle Time of External Clock Input
t cycex
3xt cyc
—
ns
2
Clock High Time
t wckh
1.5xt cyc
—
ns
3
Clock Low Time
t wckl
1xt cyc
—
ns
4
Rise Time
t rck
—
0.25xt cyc
ns
5
Fall Time
t fck
—
0.25xt cyc
ns
Table 13.2. Clock Input (Guaranteed Limit)
Clock Input (Guaranteed Limit)
Num
Characteristic
Symbol
Min
Max
Unit
6
Propagation Delay
External Clock Rise to EVO Valid
t ovr
1.5xt cyc
2.5xt cyc + 240
ns
7
Propagation Delay
External Clock Fall to EVO Valid
t ovf
1.5xt cyc
2.5xt cyc + 240
ns
1
EVI1, EVI2
4
2
3
5
EVO
6
7
Figure 13-23. Event Counter Mode 1, 2, 3 – Clock Input Timing Diagram
MOTOROLA
13-22
ELECTRICAL SPECIFICATIONS
MC68HC11G5
Table 13.3. Clock Gate Input (Guaranteed Limit)
Clock Gate Input (Required Limit)
Num
Characteristic
Symbol
Min
Max
Unit
1
Gate Input Setup Time to E Fall
t gsu
0.25xt cyc
—
ns
2
Gate Input Hold Time to E Fall
t gh
0.5xt cyc
—
ns
E Clock
1
2
Gate Input
(EVI1 or EVI2)
Figure 13-24. Event Counter Mode 1, 2, 3 – Clock Gate Input Timing Diagram
MC68HC11G5
ELECTRICAL SPECIFICATIONS
MOTOROLA
13-23
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MOTOROLA
13-24
ELECTRICAL SPECIFICATIONS
MC68HC11G5
SECTION 14
MECHANICAL DATA
This section contains the pin assignments, packaging dimensions and ordering information for the
MC68HC11G5 MCU.
14.1
ORDERING INFORMATION
MC68HC11G5
Package Type
Temperature
Part Number
PLCC (CFN Suffix)
− 40° to 85°C
MC68HC11G5CFN
MECHANICAL DATA
MOTOROLA
14-1
14.2
PIN ASSIGNMENTS
MOTOROLA
14-2
PF0/A0
PF1/A1
PF2/A2
PF3/A3
PD3/MOSI
PD2/MISO
PD1/TXD
PD0/RXD
MECHANICAL DATA
PF4/A4
PF5/A5
PF6/A6
PF7/A7
IRQ
XIRQ
RESET
HALT
VDDR
VSSR
PH7/MRDY
PH6/EVO
PH5/EVI1
PH4/EVI2
PH3/PW4
PH2/PW3
PH1/PW2
PH0/PW1
PC7/D7
PC6/D6
PC5/D5
PC1/D1
PC2/D2
PC3/D3
PC4/D4
R/W
E
PC0/D0
MODA/LIR
EXTAL
XTAL
V SS
MODB/V kam
PE5/AN6
PE2/AN3
PE6/AN7
PE3/AN4
PE7/AN8
Vrl
Vrh
11 10 9 8 7 6 5 4 3 2 1 84 83 82 81 80 79 78 77 76 75
12
74
13
73
14
72
15
71
16
70
17
69
18
68
19
67
20
66
21
65
22
64
23
63
24
62
25
61
26
60
27
59
28
58
29
57
30
56
31
55
32
54
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
PE4/AN5
PE1/AN2
PJ1/OC6/IC5
PJ0/TCK
PB7/A15
PB6/A14
PB5/A13
PB4/A12
PB3/A11
PB2/A10
PB1/A9
PB0/A8
VDDL
VSSL
PG7
PG6
PG5
PG4
PG3
PG2
PG1
PG0
PE0/AN1
PA1/IC2
PA2/IC1
PA3/OC5/IC4
PA4/OC4
PA5/OC3
PA6/OC2
PA7/OC1/PAI
PD5/SS
PD4/SCK
VDD
PJ2/OC7/IC6
PJ3
PA0/IC3
The MC68HC11G5 is offered in an 84-pin PLCC (Quad Surface Mount plastic) package.
MC68HC11G5
14.3
PACKAGE DIMENSIONS
-N-
Y BRK
B
0.18 (0.007) M T N S — P S L S — M S
D
-L-
0.18 (0.007) M T N S — P S L S — M S
U
-MZ1
W
(Note 1) 84
VIEW D-D
D
1
-P-
G1
V
X
A
0.18 (0.007) M T L S — M S N S — P S
R
0.18 (0.007) M T L S — M S N S — P S
0.25 (0.010) M T N S — P S L S — M S
Z
H
C
0.18 (0.007) M T L S —M S N S —P S
0.18 (0.007) M T N S —P S L S —M S
K1
E
0.10 (0.004)
J
G
-T- SEATING PLANE
K
DETAIL S
F
G1
0.18 (0.007) M T L S — M S N S — P S
0.18 (0.007) M T N S — P S L S — M S
DETAIL S
0.25 (0.010) S T L S — M S N S —P S
DIM
A
B
C
E
F
G
G
H
J
K
R
U
V
W
X
Y
Z
G1
K1
Z1
MC68HC11G5
MILLIMETERS
MIN
MAX
30.10 30.35
30.10 30.35
4.20
4.57
2.29
2.79
0.33
0.48
1.27 BSC
0.66
0.81
0.51
—
0.64
—
29.21 29.36
29.21 29.36
1.07
1.21
1.21
1.07
1.07
1.42
—
0.50
2°
10°
28.20 28.70
1.02
—
2°
10°
INCHES
MIN
MAX
1.185 1.195
1.185 1.195
0.165 0.180
0.090 0.110
0.013 0.019
0.050 BSC
0.026 0.032
0.020
—
0.025
—
1.150 1.156
1.150 1.156
0.042 0.048
0.042 0.056
0.042 0.056
—
0.020
2°
10°
1.110 1.130
0.040
—
2°
10°
NOTES:
1. DUE TO SPACE LIMITATION, CASE 780-01 SHALL BE
REPRESENTED BY A GENERAL CASE OUTLINE
DRAWING.
2. DATUMS -L-, -M-, -N-, AND -P- DETERMINED
WHERE TOP OF LEAD SHOULDER EXIT PLASTIC
BODY AT MOLD PARTING LINE.
3. DIM G1, TRUE POSITION TO BE MEASURED AT
DATUM -T-, SEATING PLANE
4. DIM R AND U DO NOT INCLUDE MOLD PROTRUSION.
ALLOWABLE MOLD PROTRUSION IS 0.25 (0.010) PER
SIDE
5. DIMENSIONS AND TOLERANCING PER ANSI
Y14.5M, 1982
6. CONTROLLING DIMENSION: INCH
MECHANICAL DATA
MOTOROLA
14-3
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MOTOROLA
14-4
MECHANICAL DATA
MC68HC11G5
Literature Distribution Centres:
USA: Motorola Literature Distribution; P.O. Box 20912; Phoenix, Arizona 85036.
EUROPE: Motorola Ltd.; European Literature Centre; 88 Tanners Drive, Blakelands, Milton Keynes, MK14 5BP, England.
ASIA PACIFIC: Motorola Semiconductors (H.K.) Ltd.; Silicon Harbour Center, No. 2, Dai King Street, Tai Po Industrial
Estate, Tai Po, N.T., Hong Kong.
JAPAN: Nippon Motorola Ltd.; 4-32-1, Nishi-Gotanda, Shinagawa-ku, Tokyo 141, Japan.