ATMEL AT89C51CC02CA-SISUM Enhanced 8-bit microcontroller with can controller and flash Datasheet

Features
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80C51 Core Architecture
256 Bytes of On-chip RAM
256 Bytes of On-chip XRAM
16K Bytes of On-chip Flash Memory
– Data Retention: 10 Years at 85°C
– Erase/Write Cycle: 100K
Boot Code Section with Independent Lock Bits
2K Bytes of On-chip Flash for Bootloader
In-System Programming by On-Chip Boot Program (CAN, UART) and IAP Capability
2K Bytes of On-chip EEPROM
– Erase/Write Cycle: 100K
14-sources 4-level Interrupts
Three 16-bit Timers/Counters
Full Duplex UART Compatible 80C51
Maximum Crystal Frequency 40 MHz. In X2 Mode, 20 MHz (CPU Core, 40 MHz)
Three or Four Ports: 16 or 20 Digital I/O Lines
Two-channel 16-bit PCA
– PWM (8-bit)
– High-speed Output
– Timer and Edge Capture
Double Data Pointer
21-bit Watchdog Timer (7 Programmable bits)
A 10-bit Resolution Analog-to-Digital Converter (ADC) with 8 Multiplexed Inputs
Full CAN Controller
– Fully Compliant with CAN rev.# 2.0A and 2.0B
– Optimized Structure for Communication Management (Via SFR)
– 4 Independent Message Objects
-Each Message Object Programmable on Transmission or Reception
-Individual Tag and Mask Filters up to 29-bit Identifier/Channel
-8-byte Cyclic Data Register (FIFO)/Message Object
-16-bit Status and Control Register/Message Object
-16-bit Time-Stamping Register/Message Object
-CAN Specification 2.0 Part A or 2.0 Part B Programmable for Each Message
Object
-Access to Message Object Control and Data Registers Via SFR
-Programmable Reception Buffer Length up to 4 Message Objects
-Priority Management of Reception of Hits on Several Message Objects
Simultaneously (Basic CAN Feature)
-Priority Management for Transmission
-Message Object Overrun Interrupt
– Supports
-Time Triggered Communication
-Autobaud and Listening Mode
-Programmable Automatic Reply Mode
1-Mbit/s Maximum Transfer Rate at 8 MHz(1) Crystal Frequency In X2 Mode
Readable Error Counters
Programmable Link to On-chip Timer for Time Stamping and Network Synchronization
Independent Baud Rate Prescaler
Data, Remote, Error and Overload Frame Handling
Power-saving Modes
– Idle Mode
– Power-down Mode
Power Supply: 3 Volts to 5.5 Volts
Temperature Range: Industrial (-40° to +85°C)
Packages: SOIC28, SOIC24, PLCC28, VQFP32
Note:
1. At BRP = 1 sampling point will be fixed.
Enhanced 8-bit
Microcontroller
with CAN
Controller and
Flash
T89C51CC02
AT89C51CC02
Rev. 4126L–CAN–01/08
Description
Part of the CANaryTM family of 8-bit microcontrollers dedicated to CAN network applications, the T89C51CC02 is a low-pin count 8-bit Flash microcontroller.
In X2 Mode a maximum external clock rate of 20 MHz reaches a 300 ns cycle time.
Besides the full CAN controller T89C51CC02 provides 16K Bytes of Flash memory
including In-System Programming (ISP), 2K Bytes Boot Flash Memory, 2K Bytes
EEPROM and 512 Bytes RAM.
Special attention is payed to the reduction of the electro-magnetic emission of
T89C51CC02.
RAM
256x8
UART
XTAL1
XRAM
256 x 8
PCA
Timer 2
TxDC
RxDC
T2
T2EX
PCA
ECI
Flash Boot
EE
16K x loader PROM
8
2K x 8 2K x 8
CAN
CONTROLLER
IB-bus
CPU
Watch
Dog
Note:
P4(2)
P3
P2(2)
P1(1)
INT1
INT0
T1
T0
RESET
Port 1 Port 2 Port 3 Port 4
10-bit
ADC
VAGND
Parallel I/O Ports
INT
Ctrl
VAREF
Timer 0
Timer 1
VAVCC
XTAL2
C51
CORE
Vss
Vcc
TxD
RxD
Block Diagram
1. 8 analog Inputs/8 Digital I/O.
2. 2-bit I/O Port.
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AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Pin Configurations
VAREF
VAGND
VAVCC
P4.1/RxDC
P4.0/TxDC
P2.1
P3.7
P3.6
P3.5/T1
P3.4/T0
P3.3/INT1
P3.2/INT0
1
2
3
4
5
6
7
8
9
10
11
12
P3.1/TxD
SO28
28 P1.0/AN0/T2
27 P1.1/AN1/T2EX
26 P1.2/AN2/ECI
25 P1.3/AN3/CEX0
24 P1.4/AN4/CEX1
23 P1.5/AN5
22 P1.6/AN6
21 P1.7/AN7
20 P2.0
19
18
17
RESET
VSS
VCC
13
16
XTAL1
P3.0/RxD
14
15
XTAL2
VAREF
VAGND
VAVCC
P4.1/RxDC
P4.0/TxDC
1
2
3
4
5
6
7
8
9
10
11
12
24 P1.0/AN0/T2
23 P1.1/AN1/T2EX
22 P1.2/AN2/ECI
21 P1.3/AN3/CEX0
20 P1.4/AN4/CEX1
19 P1.5/AN5
18 P1.6/AN6
17 P1.7/AN7
16 RESET
15 VSS
14 VCC
13 XTAL1
VAVCC
VAGND
VAREF
P1.0/AN 0/T2
P1.1/AN1/T2EX
P1.2/AN2/ECI
SO24
4
3
2
1
28
27
26
P4.1/RxDC
P3.5/T1
P3.4/T0
P3.3/INT1
P3.2/INT0
P3.1/TxD
P3.0/RxD
XTAL2
5
6
7
8
9
10
11
PLCC-28
25
24
23
22
21
20
19
P1.3/AN3/CEX0
P1.4/AN4/CEX1
P1.5/AN5
P1.6/AN6
P1.7/AN7
P2.0
RESET
P3.2/INT0
P3.1/TxD
P3.0/RxD
XTAL2
XTAL1
VCC
VSS
12
13
14
15
16
17
18
P4.0/TxDC
P2.1
P3.7
P3.6
P3.5/T1
P3.4/T0
P3.3/INT1
3
4126L–CAN–01/08
P4.1/RxDC
VAVCC
NC
VAGND
VAREF
P1.0/AN 0/T2
P1.1/AN1/T2EX
P1.2/AN2/ECI
32
31
30
29
28
27
26
25
QFP-32
24
23
22
21
20
19
18
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
17
P1.3/AN3/CEX0
P1.4/AN4/CEX1
P1.5/AN5
P1.6/AN6
P1.7/AN7
P2.0
NC
RESET
P3.2/INT0
P3.1/TxD
P3.0/RxD
NC
XTAL2
XTAL1
VCC
VSS
P4.0/TxDC
P2.1
P3.7
P3.6
P3.5/T1
P3.4/T0
NC
P3.3/INT1
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AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Pin Description
Pin Name
Type
Description
VSS
GND
Circuit ground
VCC
Supply Voltage
VAREF
Reference Voltage for ADC (input)
VAVCC
Supply Voltage for ADC
VAGND
Reference Ground for ADC (internaly connected with the VSS)
P1.0:7
I/O
Port 1:
Is an 8-bit bi-directional I/O port with internal pull-ups. Port 1 pins can be used for digital input/output or as
analog inputs for the Analog Digital Converter (ADC). Port 1 pins that have 1’s written to them are pulled
high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 1 pins that
are being pulled low externally will be the source of current (IIL, See section ’Electrical Characteristic’)
because of the internal pull-ups. Port 1 pins are assigned to be used as analog inputs via the ADCCF
register (in this case the internal pull-ups are disconnected).
As a secondary digital function, port 1 contains the Timer 2 external trigger and clock input; the PCA
external clock input and the PCA module I/O.
P1.0/AN0/T2
Analog input channel 0,
External clock input for Timer/counter2.
P1.1/AN1/T2EX
Analog input channel 1,
Trigger input for Timer/counter2.
P1.2/AN2/ECI
Analog input channel 2,
PCA external clock input.
P1.3/AN3/CEX0
Analog input channel 3,
PCA module 0 Entry of input/PWM output.
P1.4/AN4/CEX1
Analog input channel 4,
PCA module 1 Entry of input/PWM output.
P1.5/AN5
Analog input channel 5,
P1.6/AN6
Analog input channel 6,
P1.7/AN7
Analog input channel 7,
It can drive CMOS inputs without external pull-ups.
P2.0:1
I/O
Port 2:
Is an 2-bit bi-directional I/O port with internal pull-ups. Port 2 pins that have 1’s written to them are pulled
high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 2 pins that are being
pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pull-ups.
In the T89C51CC02 Port 2 can sink or source 5mA. It can drive CMOS inputs without external pull-ups.
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4126L–CAN–01/08
6
Pin Name
Type
Description
P3.0:7
I/O
Port 3:
Is an 8-bit bi-directional I/O port with internal pull-ups. Port 3 pins that have 1’s written to them are pulled
high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 3 pins that
are being pulled low externally will be a source of current (IIL, See section ’Electrical Characteristic’)
because of the internal pull-ups.
The output latch corresponding to a secondary function must be programmed to one for that function to
operate (except for TxD and WR). The secondary functions are assigned to the pins of port 3 as follows:
P3.0/RxD: Receiver data input (asynchronous) or data input/output (synchronous) of the serial interface
P3.1/TxD: Transmitter data output (asynchronous) or clock output (synchronous) of the serial interface
P3.2/INT0: External interrupt 0 input/timer 0 gate control input
P3.3/INT1: External interrupt 1 input/timer 1 gate control input
P3.4/T0: Timer 0 counter input
P3.5/T1: Timer 1 counter input
P3.6: Regular I/O port pin
P3.7: Regular I/O port pin
P4.0:1
I/O
Port 4:
Is an 2-bit bi-directional I/O port with internal pull-ups. Port 4 pins that have 1’s written to them are pulled
high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 4 pins that are being
pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pull-up
transistor.
The output latch corresponding to a secondary function RxDC must be programmed to one for that
function to operate. The secondary functions are assigned to the two pins of port 4 as follows:
P4.0/TxDC:
Transmitter output of CAN controller
P4.1/RxDC:
Receiver input of CAN controller.
It can drive CMOS inputs without external pull-ups.
RESET
I/O
Reset:
A high level on this pin during two machine cycles while the oscillator is running resets the device. An
internal pull-down resistor to VSS permits power-on reset using only an external capacitor to VCC.
XTAL1
I
XTAL1:
Input of the inverting oscillator amplifier and input of the internal clock generator circuits. To drive the
device from an external clock source, XTAL1 should be driven, while XTAL2 is left unconnected. To
operate above a frequency of 16 MHz, a duty cycle of 50% should be maintained.
XTAL2
O
XTAL2:
Output from the inverting oscillator amplifier.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
I/O Configurations
Each Port SFR operates via type-D latches, as illustrated in Figure 1 for Ports 3 and 4. A
CPU ’write to latch’ signal initiates transfer of internal bus data into the type-D latch. A
CPU ’read latch’ signal transfers the latched Q output onto the internal bus. Similarly, a
’read pin’ signal transfers the logical level of the Port pin. Some Port data instructions
activate the ’read latch’ signal while others activate the ’read pin’ signal. Latch instructions are referred to as Read-Modify-Write instructions. Each I/O line may be
independently programmed as input or output.
Port Structure
Figure 1 shows the structure of Ports, which have internal pull-ups. An external source
can pull the pin low. Each Port pin can be configured either for general-purpose I/O or
for its alternate input output function.
To use a pin for general-purpose output, set or clear the corresponding bit in the Px register (x = 1 to 4). To use a pin for general-purpose input, set the bit in the Px register.
This turns off the output FET drive.
To configure a pin for its alternate function, set the bit in the Px register. When the latch
is set, the ’alternate output function’ signal controls the output level (See Figure 1). The
operation of Ports is discussed further in ’Quasi-Bi-directional Port Operation’
paragraph.
Figure 1. Ports Structure
VCC
ALTERNATE
OUTPUT
FUNCTION
READ
LATCH
INTERNAL
BUS
WRITE
TO
LATCH
READ
PIN
Note:
INTERNAL
PULL-UP (1)
(1)
D
P1.x
P2.x
P3.x
P4.x
Q
LATCH
CL
ALTERNATE
INPUT
FUNCTION
1. The internal pull-up can be disabled on P1 when analog function is selected.
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4126L–CAN–01/08
Read-Modify-Write
Instructions
Some instructions read the latch data rather than the pin data. The latch based instructions read the data, modify the data and then rewrite the latch. These are called ’ReadModify-Write’ instructions. Below is a complete list of these special instructions (See
Table 1). When the destination operand is a Port or a Port bit, these instructions read
the latch rather than the pin:
Table 1. Read/Modify/Write Instructions
Instruction
Description
Example
ANL
Logical AND
ANL P1, A
ORL
Logical OR
ORL P2, A
XRL
Logical EX-OR
XRL P3, A
JBC
Jump if bit = 1 and clear bit
JBC P1.1, LABEL
CPL
Complement bit
CPL P3.0
INC
Increment
INC P2
DEC
Decrement
DEC P2
DJNZ
Decrement and jump if not zero
DJNZ P3, LABEL
MOV Px.y, C
Move carry bit to bit y of Port x
MOV P1.5, C
CLR Px.y
Clear bit y of Port x
CLR P2.4
SET Px.y
Set bit y of Port x
SET P3.3
It is not obvious that the last three instructions in this list are Read-Modify-Write instructions. These instructions read the port (all 8 bits), modify the specifically addressed bit
and write the new byte back to the latch. These Read-Modify-Write instructions are
directed to the latch rather than the pin in order to avoid possible misinterpretation of
voltage (and therefore, logic) levels at the pin. For example, a Port bit used to drive the
base of an external bipolar transistor cannot rise above the transistor’s base-emitter
junction voltage (a value lower than VIL). With a logic one written to the bit, attempts by
the CPU to read the Port at the pin are misinterpreted as logic zero. A read of the latch
rather than the pins returns the correct logic one value.
Quasi Bi-directional Port
Operation
Port 1, Port 3 and Port 4 have fixed internal pull-ups and are referred to as ’quasi-bidirectional’ Ports. When configured as an input, the pin impedance appears as logic one
and sources current in response to an external logic zero condition. Resets write logic
one to all Port latches. If logical zero is subsequently written to a Port latch, it can be
returned to input conditions by a logic one written to the latch.
Note:
Port latch values change near the end of Read-Modify-Write insruction cycles. Output
buffers (and therefore the pin state) are updated early in the instruction after Read-Modify-Write instruction cycle.
Logical zero-to-one transitions in Port 1, Port 3 and Port 4 use an additional pull-up (p1)
to aid this logic transition See Figure 2. This increases switch speed. This extra pull-up
sources 100 times normal internal circuit current during 2 oscillator clock periods. The
internal pull-ups are field-effect transistors rather than linear resistors. Pull-ups consist
of three p-channel FET (pFET) devices. A pFET is on when the gate senses logic zero
and off when the gate senses logic one. pFET #1 is turned on for two oscillator periods
immediately after a zero-to-one transition in the Port latch. A logic one at the Port pin
turns on pFET #3 (a weak pull-up) through the inverter. This inverter and pFET pair form
a latch to drive logic one. pFET #2 is a very weak pull-up switched on whenever the
8
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
associated nFET is switched off. This is traditional CMOS switch convention. Current
strengths are 1/10 that of pFET #3.
Note:
During Reset, pFET#1 is not avtivated. During Reset, only the weak pFET#3 pull up the
pin.
Figure 2. Internal Pull-up Configurations
2 Osc. PERIODS
VCC
VCC
VCC
p1(1)
p2
p3
P1.x
P2.x
P3.x
P4.x
OUTPUT DATA
n
INPUT DATA
READ PIN
9
4126L–CAN–01/08
SFR Mapping
Tables 3 through Table 11 show the Special Function Registers (SFRs) of the
T89C51CC02.
Table 2. C51 Core SFRs
Mnemonic
Add
Name
ACC
E0h Accumulator
B
F0h B Register
PSW
D0h Program Status Word
SP
81h
Stack Pointer
DPL
82h
Data Pointer Low
byte
7
6
5
4
3
2
1
0
CY
AC
F0
RS1
RS0
OV
F1
P
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
LSB of DPTR
DPH
83h
Data Pointer High
byte
MSB of DPTR
Table 3. I/O Port SFRs
Mnemonic
Add
Name
P1
90h
Port 1
P2
A0h Port 2 (x2)
P3
B0h Port 3
P4
C0h Port 4 (x2)
Table 4. Timers SFRs
Mnemonic
Add
Name
TH0
8Ch
Timer/Counter 0 High
byte
TL0
8Ah
Timer/Counter 0 Low
byte
TH1
8Dh
Timer/Counter 1 High
byte
TL1
8Bh
Timer/Counter 1 Low
byte
TH2
CDh
Timer/Counter 2 High
byte
TL2
CCh
Timer/Counter 2 Low
byte
TCON
88h
Timer/Counter 0 and
1 control
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
TMOD
89h
Timer/Counter 0 and
1 Modes
GATE1
C/T1#
M11
M01
GATE0
C/T0#
M10
M00
10
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 4. Timers SFRs (Continued)
Mnemonic
Add
Name
T2CON
C8h
Timer/Counter 2
control
T2MOD
C9h
Timer/Counter 2
Mode
RCAP2H
Timer/Counter 2
CBh Reload/Capture High
byte
RCAP2L
Timer/Counter 2
CAh Reload/Capture Low
byte
WDTRST
A6h
WatchDog Timer
Reset
WDTPRG
A7h
WatchDog Timer
Program
7
6
5
4
3
2
1
0
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2#
CP/RL2#
T2OE
DCEN
S2
S1
S0
Table 5. Serial I/O Port SFRs
Mnemonic
Add
Name
SCON
98h
Serial Control
SBUF
99h
Serial Data Buffer
SADEN
B9h Slave Address Mask
SADDR
A9h Slave Address
7
6
5
4
3
2
1
0
FE/SM0
SM1
SM2
REN
TB8
RB8
TI
RI
5
4
3
2
1
0
CCF4
CCF3
CCF2
CCF1
CCF0
CPS1
CPS0
ECF
Table 6. PCA SFRs
Mnemonic
Add
Name
7
6
CCON
D8h
PCA Timer/Counter
Control
CF
CR
CMOD
D9h
PCA Timer/Counter
Mode
CIDL
CL
E9h
PCA Timer/Counter
Low byte
CH
F9h
PCA Timer/Counter
High byte
CCAPM0
PCA Timer/Counter
DAh Mode 0
CCAPM1
CCAP0H
CCAP1H
ECOM0
CAPP0
CAPN0
MAT0
TOG0
PWM0
ECCF0
ECOM1
CAPP1
CAPN1
MAT1
TOG1
PWM1
ECCF1
CCAP0H7
CCAP0H6
CCAP0H5
CCAP0H4
CCAP0H3
CCAP0H2
CCAP0H1
CCAP0H0
CCAP1H7
CCAP1H6
CCAP1H5
CCAP1H4
CCAP1H3
CCAP1H2
CCAP1H1
CCAP1H0
DBh PCA Timer/Counter
Mode 1
PCA Compare
FAh Capture Module 0 H
FBh PCA Compare
Capture Module 1 H
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4126L–CAN–01/08
Table 6. PCA SFRs (Continued)
Mnemonic
Add
CCAP0L
PCA Compare
EAh Capture Module 0 L
CCAP1L
Name
EBh PCA Compare
Capture Module 1 L
7
6
5
4
3
2
1
0
CCAP0L7
CCAP0L6
CCAP0L5
CCAP0L4
CCAP0L3
CCAP0L2
CCAP0L1
CCAP0L0
CCAP1L7
CCAP1L6
CCAP1L5
CCAP1L4
CCAP1L3
CCAP1L2
CCAP1L1
CCAP1L0
Table 7. Interrupt SFRs
Mnemonic
Add
Name
7
6
5
4
3
2
1
0
IEN0
A8h
Interrupt Enable
Control 0
EA
EC
ET2
ES
ET1
EX1
ET0
EX0
IEN1
E8h
Interrupt Enable
Control 1
ETIM
EADC
ECAN
IPL0
B8h
Interrupt Priority
Control Low 0
PPC
PT2
PS
PT1
PX1
PT0
PX0
IPH0
B7h
Interrupt Priority
Control High 0
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
IPL1
F8h
Interrupt Priority
Control Low 1
POVRL
PADCL
PCANL
IPH1
F7h
Interrupt Priority
Control High1
POVRH
PADCH
PCANH
Table 8. ADC SFRs
Mnemonic
Add
Name
7
ADCON
F3h ADC Control
ADCF
F6h ADC Configuration
ADCLK
F2h ADC Clock
ADDH
F5h ADC Data High byte
ADDL
F4h ADC Data Low byte
6
5
4
3
2
1
0
PSIDLE
ADEN
ADEOC
ADSST
SCH2
SCH1
SCH0
CH6
CH5
CH4
CH3
CH2
CH1
CH0
PRS4
PRS3
PRS2
PRS1
PRS0
ADAT6
ADAT5
ADAT4
ADAT3
ADAT2
ADAT1
ADAT0
CH7
ADAT9
ADAT8
ADAT7
Table 9. CAN SFRs
Mnemonic
Add Name
CANGCON
ABh
CAN General
Control
CANGSTA
AAh
CAN General
Status
CANGIT
9Bh
CAN General
Interrupt
CANBT1
B4h
CAN bit Timing 1
CANBT2
B5h
CANBT3
B6h
12
7
6
ABRQ
OVRQ
5
TTC
4
3
2
1
0
SYNCTTC
AUT-BAUD
TEST
ENA
GRES
TBSY
RBSY
ENFG
BOFF
ERRP
OVRTIM
OVRBUF
SERG
CERG
FERG
AERG
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
CAN bit Timing 2
SJW1
SJW0
PRS2
PRS1
PRS0
CAN bit Timing 3
PHS22
PHS21
PHS12
PHS11
PHS10
OVFG
CANIT
PHS20
SMP
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 9. CAN SFRs (Continued)
Mnemonic
Add Name
3
2
1
0
CANEN
CFh
CAN Enable
Channel byte
ENCH3
ENCH2
ENCH1
ENCH0
CANGIE
C1h
CAN General
Interrupt Enable
ENERCH
ENBUF
ENERG
CANIE
C3h
CAN Interrupt
Enable Channel
byte
IECH3
IECH2
IECH1
IECH0
CANSIT
BBh
CAN Status Interrupt
Channel byte
SIT3
SIT2
SIT1
SIT0
CANTCON
A1h
CAN Timer Control
TPRESC 7
TPRESC 6
TPRESC 5
TPRESC 4
TPRESC 3
TPRESC 2
TPRESC 1
TPRESC 0
CANTIMH
ADh
CAN Timer high
CANTIM 15
CANTIM 14
CANTIM 13
CANTIM 12
CANTIM 11
CANTIM 10
CANTIM 9
CANTIM 8
CANTIML
ACh
CAN Timer low
CANTIM 7
CANTIM 6
CANTIM 5
CANTIM 4
CANTIM 3
CANTIM 2
CANTIM 1
CANTIM 0
CANSTMPH
AFh
CAN Timer Stamp
high
TIMSTMP
15
TIMSTMP
14
TIMSTMP
13
TIMSTMP
12
TIMSTMP 11
TIMSTMP
10
TIMSTMP 9
TIMSTMP 8
CANSTMPL
AEh
CAN Timer Stamp
low
TIMSTMP7
TIMSTMP 6
TIMSTMP 5
TIMSTMP 4
TIMSTMP 3
TIMSTMP 2
TIMSTMP 1
TIMSTMP 0
CANTTCH
A5h
CAN Timer TTC
high
TIMTTC 15
TIMTTC 14
TIMTTC 13
TIMTTC 12
TIMTTC 11
TIMTTC 10
TIMTTC
9
TIMTTC
8
CANTTCL
A4h
CAN Timer TTC low
TIMTTC
7
TIMTTC
6
TIMTTC
5
TIMTTC
4
TIMTTC
3
TIMTTC
2
TIMTTC
1
TIMTTC
0
CANTEC
9Ch
CAN Transmit Error
Counter
TEC7
TEC6
TEC5
TEC4
TEC3
TEC2
TEC1
TEC0
CANREC
9Dh
CAN Receive Error
Counter
REC7
REC6
REC5
REC4
REC3
REC2
REC1
REC0
CANPAGE
B1h
CAN Page
-
-
CHNB1
CHNB0
AINC
INDX2
INDX1
INDX0
CANSTCH
B2h
CAN Status Channel
DLCW
TXOK
RXOK
BERR
SERR
CERR
FERR
AERR
CANCONCH
B3h
CAN Control
Channel
CONCH1
CONCH0
RPLV
IDE
DLC3
DLC2
DLC1
DLC0
CANMSG
A3h
CAN Message Data
MSG7
MSG6
MSG5
MSG4
MSG3
MSG2
MSG1
MSG0
CANIDT1
BCh
CAN Identifier Tag
byte 1(Part A)
CAN Identifier Tag
byte 1(PartB)
IDT10
IDT28
IDT9
IDT27
IDT8
IDT26
IDT7
IDT25
IDT6
IDT24
IDT5
IDT23
IDT4
IDT22
IDT3
IDT21
BDh
CAN Identifier Tag
byte 2 (PartA)
CAN Identifier Tag
byte 2 (PartB)
IDT2
IDT20
IDT1
IDT19
IDT0
IDT18
IDT17
IDT16
IDT15
IDT14
IDT13
CAN Identifier
Tag byte 3(PartA)
-
-
-
-
-
-
-
-
CAN Identifier
Tag byte 3(PartB)
IDT12
IDT11
IDT10
IDT9
IDT8
IDT7
IDT6
IDT5
CAN Identifier
Tag byte 4(PartA)
-
-
-
-
-
CAN Identifier
Tag byte 4(PartB)
IDT4
IDT3
IDT2
IDT1
IDT0
IDMSK10
IDMSK9
IDMSK8
IDMSK7
IDMSK6
IDMSK5
IDMSK4
IDMSK3
IDMSK28
IDMSK27
IDMSK26
IDMSK25
IDMSK24
IDMSK23
IDMSK22
IDMSK21
CANIDT2
CANIDT3
CANIDT4
CANIDM1
BEh
BFh
C4h
CAN Identifier Mask
byte 1(PartA)
CAN Identifier Mask
byte 1(PartB)
7
6
5
ENRX
4
ENTX
RB0TAG
RTRTAG
RB1TAG
13
4126L–CAN–01/08
Table 9. CAN SFRs (Continued)
Mnemonic
Add Name
CANIDM2
C5h
CANIDM3
CANIDM4
C6h
C7h
CAN Identifier Mask
byte 2(PartA)
CAN Identifier Mask
byte 2(PartB)
CAN Identifier Mask
byte 3(PartA)
CAN Identifier Mask
byte 3(PartB)
CAN Identifier Mask
byte 4(PartA)
CAN Identifier Mask
byte 4(PartB)
7
6
5
4
3
2
1
0
IDMSK2
IDMSK1
IDMSK0
-
-
-
-
-
IDMSK20
IDMSK19
IDMSK18
IDMSK17
IDMSK16
IDMSK15
IDMSK14
IDMSK13
-
-
-
-
-
-
-
-
IDMSK12
IDMSK11
IDMSK10
IDMSK9
IDMSK8
IDMSK7
IDMSK6
IDMSK5
-
-
-
-
RTRMSK
-
IDEMSK
IDMSK4
IDMSK3
IDMSK2
IDMSK1
IDMSK0
7
6
SMOD1
SMOD0
Table 10. Other SFRs
Mnemonic
Add
Name
4
3
2
1
0
POF
GF1
GF0
PD
IDL
GF3
0
PCON
87h
AUXR1
A2h Auxiliary Register 1
CKCON
8Fh Clock Control
CANX2
WDX2
PCAX2
SIX2
T2X2
T1X2
T0X2
X2
FCON
D1h Flash Control
FPL3
FPL2
FPL1
FPL0
FPS
FMOD1
FMOD0
FBUSY
EECON
D2h EEPROM Contol
EEPL3
EEPL2
EEPL1
EEPL0
EEE
EEBUSY
14
Power Control
5
ENBOOT
DPS
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 11. SFR Mapping
0/8(1)
1/9
2/A
3/B
F8h
IPL1
xxxx x000
CH
0000 0000
CCAP0H
0000 0000
CCAP1H
0000 0000
F0h
B
0000 0000
ADCLK
xxx0 0000
ADCON
x000 0000
E8h
IEN1
xxxx x000
CCAP0L
0000 0000
CCAP1L
0000 0000
E0h
ACC
0000 0000
D8h
CCON
0000 0000
CMOD
0xxx x000
CCAPM0
x000 0000
D0h
PSW
0000 0000
FCON
0000 0000
EECON
xxxx xx00
C8h
T2CON
0000 0000
T2MOD
xxxx xx00
RCAP2L
0000 0000
C0h
P4
xxxx xx11
B8h
CL
0000 0000
4/C
5/D
ADDL
0000 0000
ADDH
0000 0000
IPH1
xxxx x000
F7h
E7h
CCAPM1
x000 0000
DFh
D7h
CANEN
xxxx 0000
CFh
CANIDM3
xxxx xxxx
CANIDM4
xxxx xxxx
C7h
CANIDT2
xxxx xxxx
CANIDT3
xxxx xxxx
CANIDT4
xxxx xxxx
BFh
CANBT1
xxxx xxxx
CANBT2
xxxx xxxx
CANBT3
xxxx xxxx
IPH0
x000 0000
B7h
CANGCON
0000 0000
CANTIML
0000 0000
CANTIMH
0000 0000
CANSTMPL
xxxx xxxx
CANSTMPH
xxxx xxxx
AFh
CANMSG
xxxx xxxx
CANTTCL
0000 0000
CANTTCH
0000 0000
WDTRST
1111 1111
WDTPRG
xxxx x000
A7h
CANGIT
0x00 0000
CANTEC
0000 0000
0000 0000
TH2
0000 0000
1100 0000
CANIE
1111 0000
CANIDM1
xxxx xxxx
CANIDM2
xxxx xxxx
IPL0
x000 0000
SADEN
0000 0000
CANSIT
xxxx 0000
CANIDT1
xxxx xxxx
B0h
P3
1111 1111
CANPAGE
1100 0000
CANSTCH
xxxx xxxx
CANCONCH
xxxx xxxx
A8h
IEN0
0000 0000
SADDR
0000 0000
CANGSTA
1010 0000
P2
xxxx xx11
CANTCON
0000 0000
AUXR1(2)
xxxx 00x0
98h
SCON
0000 0000
SBUF
0000 0000
90h
P1
1111 1111
88h
TCON
0000 0000
0/8(1)
ADCF
0000 0000
EFh
TL2
0000 0000
80h
7/F
FFh
RCAP2H
0000 0000
A0h
6/E
CANGIE
CANREC
9Fh
97h
TMOD
0000 0000
TL0
0000 0000
TL1
0000 0000
SP
0000 0111
DPL
0000 0000
DPH
0000 0000
1/9
2/A
3/B
TH0
0000 0000
4/C
TH1
0000 0000
5/D
6/E
CKCON
0000 0000
8Fh
PCON
00x1 0000
87h
7/F
Reserved
Notes:
1. These registers are bit-addressable.
Sixteen addresses in the SFR space are both byte-addressable and bit-addressable. The bit-addressable SFRs are those
whose address ends in 0 and 8. The bit addresses, in this area, are 0x80 through to 0xFF.
2. AUXR1 bit ENBOOT is initialized with the content of the BLJB bit inverted.
15
4126L–CAN–01/08
Clock
The T89C51CC02 core needs only 6 clock periods per machine cycle. This feature,
called “X2”, provides the following advantages:
•
Divides frequency crystals by 2 (cheaper crystals) while keeping the same CPU
power.
•
Saves power consumption while keeping the same CPU power (oscillator power
saving).
•
Saves power consumption by dividing dynamic operating frequency by 2 in
operating and idle modes.
•
Increases CPU power by 2 while keeping the same crystal frequency.
In order to keep the original C51 compatibility, a divider-by-2 is inserted between the
XTAL1 signal and the main clock input of the core (phase generator). This divider may
be disabled by the software.
An extra feature is available to start after Reset in the X2 Mode. This feature can be
enabled by a bit X2B in the Hardware Security Byte. This bit is described in the section
’In-System Programming’.
Description
The X2 bit in the CKCON register (See Table 12) allows switching from 12 clock cycles
per instruction to 6 clock cycles and vice versa. At reset, the standard speed is activated
(STD mode).
Setting this bit activates the X2 feature (X2 Mode) for the CPU Clock only (See Figure
3).
The Timers 0, 1 and 2, Uart, PCA, watchdog or CAN switch in X2 Mode only if the corresponding bit is cleared in the CKCON register.
The clock for the whole circuit and peripheral is first divided by two before being used by
the CPU core and peripherals. This allows any cyclic ratio to be accepted on the XTAL1
input. In X2 Mode, as this divider is bypassed, the signals on XTAL1 must have a cyclic
ratio between 40 to 60%. Figure 3. shows the clock generation block diagram. The X2
bit is validated on the XTAL1 ÷ 2 rising edge to avoid glitches when switching from the
X2 to the STD mode. Figure 4 shows the mode switching waveforms.
16
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 3. Clock CPU Generation Diagram
X2B
Hardware Byte
PCON.0
On RESET
IDL
X2
CKCON.0
÷2
XTAL1
CPU Core
Clock
0
1
XTAL2
CPU
CLOCK
PD
CPU Core Clock Symbol
and ADC
PCON.1
÷2
1
FT0 Clock
0
÷2
1
FT1 Clock
0
÷2
1
FT2 Clock
0
÷2
1
FUart Clock
0
÷2
1
FPca Clock
0
÷2
1
FWd Clock
0
÷2
1
FCan Clock
0
PERIPH
CLOCK
X2
CKCON.0
Peripheral Clock Symbol
CANX2
WDX2
PCAX2
SIX2
T2X2
T1X2
T0X2
CKCON.7
CKCON.6
CKCON.5
CKCON.4
CKCON.3
CKCON.2
CKCON.1
17
4126L–CAN–01/08
Figure 4. Mode Switching Waveforms(1)
XTAL1
XTAL2
X2 bit
CPU
clock
STD
Mode
Note:
18
X2
Mode
STD
Mode
1. In order to prevent any incorrect operation while operating in the X2 Mode, users must be aware that all peripherals using
the clock frequency as a time reference (UART, timers...) will have their time reference divided by 2. For example, a free running timer generating an interrupt every 20 ms will then generate an interrupt every 10 ms. A UART with a 4800 baud rate
will have a 9600 baud rate.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Register
Table 12. CKCON Register
CKCON (S:8Fh)
Clock Control Register
7
6
5
4
3
2
1
0
CANX2
WDX2
PCAX2
SIX2
T2X2
T1X2
T0X2
X2
Bit
Number
CANX2
CAN Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
6
WDX2
Watchdog Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
5
PCAX2
Programmable Counter Array Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
4
SIX2
Enhanced UART clock (MODE 0 and 2) (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
3
T2X2
Timer 2 Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
2
T1X2
Timer 1 Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
1
T0X2
Timer 0 Clock (1)
Clear to select 6 clock periods per peripheral clock cycle.
Set to select 12 clock periods per peripheral clock cycle.
7
0
Note:
Bit
Mnemonic Description
X2
CPU Clock
Clear to select 12 clock periods per machine cycle (STD mode) for CPU and all
the peripherals.
Set to select 6 clock periods per machine cycle (X2 Mode) and to enable the
individual peripherals ’X2’ bits.
1. This control bit is validated when the CPU clock bit X2 is set; when X2 is low, this bit
has no effect.
Reset Value = 0000 0000b
19
4126L–CAN–01/08
Power Management
Two power reduction modes are implemented in the A/T89C51CC02: the Idle mode and
the Power-down mode. These modes are detailed in the following sections. In addition
to these power reduction modes, the clocks of the core and peripherals can be dynamically divided by 2 using the X2 Mode detailed in Section “Clock”.
Reset Pin
In order to start-up (cold reset) or to restart (warm reset) properly the microcontroller, a
high level has to be applied on the RST pin. A bad level leads to a wrong initialisation of
the internal registers like SFRs, PC, etc. and to unpredictable behavior of the microcontroller. A warm reset can be applied either directly on the RST pin or indirectly by an
internal reset source such as a watchdog, PCA, timer, etc.
At Power-up (cold reset)
Two conditions are required before enabling a CPU start-up:
•
VDD must reach the specified VDD range,
•
The level on xtal1 input must be outside the specification (VIH, VIL).
If one of these two conditions are not met, the microcontroller does not start correctly
and can execute an instruction fetch from anywhere in the program space. An active
level applied on the RST pin must be maintained until both of the above conditions are
met. A reset is active when the level VIH1 is reached and when the pulse width covers
the period of time where VDD and the oscillator are not stabilized. Two parameters have
to be taken into account to determine the reset pulse width:
•
VDD rise time (vddrst),
•
Oscillator startup time (oscrst).
To determine the capacitor the highest value of these two parameters has to be chosen.
The reset circuitry is shown in Figure 5.
Figure 5. Reset Circuitry
VDD
Crst
RST pin
Internal reset
Rrst
Reset input circuitry
0
Table 13 and Table 14 give some typical examples for three values of VDD rise times,
two values of oscillator start-up time and two pull-down resistor values.
Table 13. Minimum Reset Capacitor for a 50K Pull-down Resistor
20
oscrst/vddrst
1ms
10ms
100ms
5ms
820nF
1.2µF
12µF
20ms
2.7µF
3.9µF
12µF
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 14. Minimum Reset Capacitor for a 15k Pull-down Resistor
oscrst/vddrst
1ms
10ms
100ms
5ms
2.7µF
4.7µF
47µF
20ms
10µF
15µF
47µF
Note:
These values assume VDD starts from 0v to the nominal value. If the time between two
on/off sequences is too fast, the power-supply decoupling capacitors may not be fully
discharged, leading to a bad reset sequence.
During a Normal
Operation (Warm Reset)
Reset pin must be maintained for at least 2 machine cycles (24 oscillator clock periods)
to apply a reset sequence during normal operation. The number of clock periods is
mode independent (X2 or X1).
Watchdog Reset
A 1K resistor must be added in series with the capacitor to allow the use of watchdog
reset pulse output on the RST pin or when an external power-supply supervisor is used.
Figure 6 shows the reset circuitry when a capacitor is used.
Figure 6. Reset Circuitry for a Watchdog Configuration
VDD
Crst
watchdog
1k
RST pin
Internal reset
Rrst
Reset input circuitry
To other on-board circuitry
Figure 7 shows the reset circuitry when an external reset circuit is used.
Figure 7. Reset Circuitry Example Using an External Reset Circuit
VDD
watchdog
External reset
circuit
1k
RST pin
RST
Internal reset
Rrst
Reset input circuitry
To other on-board circuitry
21
4126L–CAN–01/08
Reset Recommendation
to Prevent Flash
Corruption
When a Flash program memory is embedded on-chip, it is strongly recommended to
use an external reset chip (brown out device) to apply a reset (Figure 7). It prevents system malfunction during periods of insufficient power-supply voltage (power-supply
failure, power supply switched off, etc.).
Idle Mode
Idle mode is a power reduction mode that reduces the power consumption. In this mode,
program execution halts. Idle mode freezes the clock to the CPU at known states while
the peripherals continue to be clocked. The CPU status before entering Idle mode is
preserved, i.e., the program counter and program status word register retain their data
for the duration of Idle mode. The contents of the SFRs and RAM are also retained. The
status of the Port pins during Idle mode is detailed in Table 15.
Entering Idle Mode
To enter Idle mode, set the IDL bit in PCON register (See Table 16). The
A/T89C51CC02 enters Idle mode upon execution of the instruction that sets IDL bit. The
instruction that sets IDL bit is the last instruction executed.
Note:
Exiting Idle Mode
If IDL bit and PD bit are set simultaneously, the A/T89C51CC02 enters Power-down
mode. Then it does not go in Idle mode when exiting Power-down mode.
There are two ways to exit Idle mode:
1. Generate an enabled interrupt.
Hardware clears IDL bit in PCON register which restores the clock to the CPU. Execution resumes with the interrupt service routine. Upon completion of the interrupt
service routine, program execution resumes with the instruction immediately following the instruction that activated Idle mode. The general purpose flags (GF1 and
GF0 in PCON register) may be used to indicate whether an interrupt occurred during normal operation or during Idle mode. When Idle mode is exited by an interrupt,
the interrupt service routine may examine GF1 and GF0.
2. Generate a reset.
A logic high on the RST pin clears IDL bit in PCON register directly and asynchronously. This restores the clock to the CPU. Program execution momentarily
resumes with the instruction immediately following the instruction that activated the
Idle mode and may continue for a number of clock cycles before the internal reset
algorithm takes control. Reset initializes the A/T89C51CC02 and vectors the CPU to
address C:0000h.
Notes:
1. During the time that execution resumes, the internal RAM cannot be accessed; however, it is possible for the Port pins to be accessed. To avoid unexpected outputs at
the Port pins, the instruction immediately following the instruction that activated Idle
mode should not write to a Port pin or to the external RAM.
2. If Idle mode is invoked by ADC Idle, the ADC conversion completion will exit Idle.
Power-down Mode
The Power-down mode places the A/T89C51CC02 in a very low power state. Powerdown mode stops the oscillator, freezes all clock at known states. The CPU status prior
to entering Power-down mode is preserved, i.e., the program counter, program status
word register retain their data for the duration of Power-down mode. In addition, the
SFRs and RAM contents are preserved. The status of the Port pins during Power-down
mode is detailed in Table 15.
Entering Power-down Mode
To enter Power-down mode, set PD bit in PCON register. The A/T89C51CC02 enters
the Power-down mode upon execution of the instruction that sets PD bit. The instruction
that sets PD bit is the last instruction executed.
22
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Exiting Power-down Mode
Note:
If VDD was reduced during the Power-down mode, do not exit Power-down mode until
VDD is restored to the normal operating level.
There are two ways to exit the Power-down mode:
1. Generate an enabled external interrupt.
–
Notes:
The A/T89C51CC02 provides capability to exit from Power-down using
INT0#, INT1#.
Hardware clears PD bit in PCON register which starts the oscillator and
restores the clocks to the CPU and peripherals. Using INTx# input,
execution resumes when the input is released (See Figure 8). Execution
resumes with the interrupt service routine. Upon completion of the interrupt
service routine, program execution resumes with the instruction immediately
following the instruction that activated Power-down mode.
1. The external interrupt used to exit Power-down mode must be configured as level
sensitive (INT0# and INT1#) and must be assigned the highest priority. In addition,
the duration of the interrupt must be long enough to allow the oscillator to stabilize.
The execution will only resume when the interrupt is deasserted.
2. Exit from power-down by external interrupt does not affect the SFRs nor the internal
RAM content.
Figure 8. Power-down Exit Waveform Using INT1:0#
INT1:0#
OSC
Active phase
Power-down phase
Oscillator restart phase
Active phase
2. Generate a reset.
–
Notes:
A logic high on the RST pin clears PD bit in PCON register directly and
asynchronously. This starts the oscillator and restores the clock to the CPU
and peripherals. Program execution momentarily resumes with the
instruction immediately following the instruction that activated Power-down
mode and may continue for a number of clock cycles before the internal
reset algorithm takes control. Reset initializes the A/T89C51CC02 and
vectors the CPU to address 0000h.
1. During the time that execution resumes, the internal RAM cannot be accessed; however, it is possible for the Port pins to be accessed. To avoid unexpected outputs at
the Port pins, the instruction immediately following the instruction that activated the
Power-down mode should not write to a Port pin or to the external RAM.
2. Exit from power-down by reset redefines all the SFRs, but does not affect the internal
RAM content.
23
4126L–CAN–01/08
Table 15. Pin Conditions in Special Operating Modes
24
Mode
Port 1
Port 2
Port 3
Port 4
Reset
High
High
High
High
Idle
(internal
code)
Data
Data
Data
Data
Idle
(external
code)
Data
Data
Data
Data
PowerDown(inter
nal code)
Data
Data
Data
Data
PowerDown
(external
code)
Data
Data
Data
Data
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Registers
Table 16. PCON Register
PCON (S:87h)
Power Control Register
7
6
5
4
3
2
1
0
SMOD1
SMOD0
-
POF
GF1
GF0
PD
IDL
Bit
Number
Bit
Mnemonic Description
7
SMOD1
Serial port Mode bit 1
Set to select double baud rate in mode 1, 2 or 3.
6
SMOD0
Serial port Mode bit 0
Clear to select SM0 bit in SCON register.
Set to select FE bit in SCON register.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
POF
Power-off Flag
Clear to recognize next reset type.
Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set by
software.
3
GF1
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
2
GF0
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
1
PD
Power-down Mode bit
Cleared by hardware when reset occurs.
Set to enter power-down mode.
0
IDL
Idle Mode bit
Clear by hardware when interrupt or reset occurs.
Set to enter idle mode.
Reset Value = 00X1 0000b
Not bit addressable
25
4126L–CAN–01/08
Data Memory
The T89C51CC02 provides data memory access in two different spaces:
The internal space mapped in three separate segments:
•
The lower 128 Bytes RAM segment.
•
The upper 128 Bytes RAM segment.
•
The expanded 256 Bytes RAM segment (XRAM).
A fourth internal segment is available but dedicated to Special Function Registers,
SFRs, (addresses 80h to FFh) accessible by direct addressing mode.
Figure 9 shows the internal data memory spaces organization.
Figure 9. Internal memory - RAM
FFh
FFh
256 Bytes
Internal XRAM
00h
FFh
Upper
128 Bytes
Internal RAM
Indirect Addressing
80h
7Fh
00h
Special
Function
Registers
Direct Addressing
80h
Lower
128 Bytes
Internal RAM
Direct or Indirect
Addressing
Internal Space
Lower 128 Bytes RAM
The lower 128 Bytes of RAM (See Figure 10) are accessible from address 00h to 7Fh
using direct or indirect addressing modes. The lowest 32 Bytes are grouped into 4
banks of 8 registers (R0 to R7). Two bits RS0 and RS1 in PSW register (See Table 18)
select which bank is in use according to Table 17. This allows more efficient use of code
space, since register instructions are shorter than instructions that use direct addressing, and can be used for context switching in interrupt service routines.
Table 17. Register Bank Selection
RS1
RS0
Description
0
0
Register bank 0 from 00h to 07h
0
1
Register bank 0 from 08h to 0Fh
1
0
Register bank 0 from 10h to 17h
1
1
Register bank 0 from 18h to 1Fh
The next 16 Bytes above the register banks form a block of bit-addressable memory
space. The C51 instruction set includes a wide selection of singlebit instructions, and
the 128 bits in this area can be directly addressed by these instructions. The bit
addresses in this area are 00h to 7Fh.
26
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 10. Lower 128 Bytes Internal RAM Organization
7Fh
30h
2Fh
20h
18h
10h
08h
00h
bit-Addressable Space
(bit Addresses 0-7Fh)
1Fh
17h
0Fh
4 Banks of
8 Registers
R0-R7
07h
Upper 128 Bytes RAM
The upper 128 Bytes of RAM are accessible from address 80h to FFh using only indirect
addressing mode.
Expanded RAM
The on-chip 256 Bytes of expanded RAM (XRAM) are accessible from address 0000h to
00FFh using indirect addressing mode through MOVX instructions. In this address
range.
Note:
Lower 128 Bytes RAM, Upper 128 Bytes RAM, and expanded RAM are made of volatile
memory cells. This means that the RAM content is indeterminate after power-up and
must then be initialized properly.
27
4126L–CAN–01/08
Dual Data Pointer
Description
The T89C51CC02 implements a second data pointer for speeding up code execution
and reducing code size in case of intensive usage of external memory accesses.
DPTR0 and DPTR1 are Seen by the CPU as DPTR and are accessed using the SFR
addresses 83h and 84h that are the DPH and DPL addresses. The DPS bit in AUXR1
register (See Figure 19) is used to select whether DPTR is the data pointer 0 or the data
pointer 1 (See Figure 11).
Figure 11. Dual Data Pointer Implementation
DPL0
0
DPL1
1
DPL
DPTR0
DPS
DPTR1
DPH0
0
DPH1
1
AUXR1.0
DPTR
DPH
Application
Software can take advantage of the additional data pointers to both increase speed and
reduce code size, for example, block operations (copy, compare…) are well served by
using one data pointer as a “source” pointer and the other one as a “destination” pointer.
Hereafter is an example of block move implementation using the two pointers and coded
in assembler. The latest C compiler takes also advantage of this feature by providing
enhanced algorithm libraries.
The INC instruction is a short (2 Bytes) and fast (6 machine cycle) way to manipulate the
DPS bit in the AUXR1 register. However, note that the INC instruction does not directly
force the DPS bit to a particular state, but simply toggles it. In simple routines, such as
the block move example, only the fact that DPS is toggled in the proper sequence matters, not its actual value. In other words, the block move routine works the same whether
DPS is 0 or 1 on entry.
; ASCII block move using dual data pointers
; Modifies DPTR0, DPTR1, A and PSW
; Ends when encountering NULL character
; Note: DPS exits opposite to the entry state unless an extra INC AUXR1 is
added
AUXR1EQU0A2h
move:movDPTR,#SOURCE ; address of SOURCE
incAUXR1 ; switch data pointers
movDPTR,#DEST ; address of DEST
mv_loop:incAUXR1; switch data pointers
movxA,@DPTR; get a byte from SOURCE
incDPTR; increment SOURCE address
incAUXR1; switch data pointers
movx@DPTR,A; write the byte to DEST
incDPTR; increment DEST address
jnzmv_loop; check for NULL terminator
end_move:
28
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AT/T89C51CC02
Registers
Table 18. PSW Register
PSW (S:D0h)
Program Status Word Register
7
6
5
4
3
2
1
0
CY
AC
F0
RS1
RS0
OV
F1
P
Bit
Number
Bit
Mnemonic Description
7
CY
Carry Flag
Carry out from bit 1 of ALU operands.
6
AC
Auxiliary Carry Flag
Carry out from bit 1 of addition operands.
5
F0
User Definable Flag 0
4-3
RS1:0
Register Bank Select bits
Refer to Table 17 for bits description.
2
OV
Overflow Flag
Overflow set by arithmetic operations.
1
F1
User Definable Flag 1
0
P
Parity bit
Set when ACC contains an odd number of 1’s.
Cleared when ACC contains an even number of 1’s.
Reset Value = 0000 0000b
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4126L–CAN–01/08
Table 19. AUXR1 Register
AUXR1 (S:A2h)
Auxiliary Control Register 1
7
6
5
4
3
2
1
0
-
-
ENBOOT
-
GF3
0
-
DPS
Bit
Number
Bit
Mnemonic
Description
7-6
-
5
Reserved
The value read from these bits is indeterminate. Do not set these bits.
Enable Boot Flash
ENBOOT(1) Set this bit to map the boot Flash between F800h -FFFFh
Clear this bit to disable boot Flash.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
3
GF3
2
0
Always Zero
This bit is stuck to logic 0 to allow INC AUXR1 instruction without affecting GF3
flag.
1
-
Reserved for Data Pointer Extension
0
DPS
General Purpose Flag 3
Data Pointer Select bit
Set to select second dual data pointer: DPTR1.
Clear to select first dual data pointer: DPTR0.
Reset Value = XXXX 00X0b
Note:
30
1. ENBOOT is initialized with the invert BLJB at reset. See In-System Programming
section.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
EEPROM Data
Memory
The 2K bytes on-chip EEPROM memory block is located at addresses 0000h to 07FFh
of the XRAM/XRAM memory space and is selected by setting control bits in the EECON
register. A read in the EEPROM memory is done with a MOVX instruction.
A physical write in the EEPROM memory is done in two steps: write data in the column
latches and transfer of all data latches into an EEPROM memory row (programming).
The number of data written on the page may vary from 1 up to 128 Bytes (the page
size). When programming, only the data written in the column latch is programmed and
a ninth bit is used to obtain this feature. This provides the capability to program the
whole memory by Bytes, by page or by a number of Bytes in a page. Indeed, each ninth
bit is set when the writing the corresponding byte in a row and all these ninth bits are
reset after the writing of the complete EEPROM row.
Write Data in the Column
Latches
Data is written by byte to the column latches as for an external RAM memory. Out of the
11 address bits of the data pointer, the 4 MSBs are used for page selection (row) and 7
are used for byte selection. Between two EEPROM programming sessions, all the
addresses in the column latches must stay on the same page, meaning that the 4 MSB
must no be changed.
The following procedure is used to write to the column latches:
•
Save and disable interrupt
•
Set bit EEE of EECON register
•
Load DPTR with the address to write
•
Store A register with the data to be written
•
Execute a MOVX @DPTR, A
•
If needed loop the three last instructions until the end of a 128 Bytes page
•
Restore interrupt
Note:
Programming
The EEPROM programming consists of the following actions:
•
Write one or more Bytes of one page in the column latches. Normally, all Bytes must
belong to the same page; if not, the last page address will be latched and the others
discarded.
•
Launch programming by writing the control sequence (50h followed by A0h) to the
EECON register.
•
EEBUSY flag in EECON is then set by hardware to indicate that programming is in
progress and that the EEPROM segment is not available for reading.
•
The end of programming is indicated by a hardware clear of the EEBUSY flag.
Note:
Read Data
The last page address used when loading the column latch is the one used to select the
page programming address.
The sequence 5xh and Axh must be executed without instructions between then otherwise the programming is aborted.
The following procedure is used to read the data stored in the EEPROM memory:
•
Save and disable interrupt
•
Set bit EEE of EECON register
•
Load DPTR with the address to read
•
Execute a MOVX A, @DPTR
•
Restore interrupt
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4126L–CAN–01/08
Examples
;*F*************************************************************************
;* NAME: api_rd_eeprom_byte
;* DPTR contain address to read.
;* Acc contain the reading value
;* NOTE: before execute this function, be sure the EEPROM is not BUSY
;***************************************************************************
api_rd_eeprom_byte:
; Save and clear EA
MOV
EECON, #02h; map EEPROM in XRAM space
MOVX A, @DPTR
MOV
EECON, #00h; unmap EEPROM
; Restore EA
ret
;*F*************************************************************************
;* NAME: api_ld_eeprom_cl
;* DPTR contain address to load
;* Acc contain value to load
;* NOTE: in this example we load only 1 byte, but it is possible upto
;* 128 Bytes.
;* before execute this function, be sure the EEPROM is not BUSY
;***************************************************************************
api_ld_eeprom_cl:
; Save and clear EA
MOV
EECON, #02h ; map EEPROM in XRAM space
MOVX @DPTR, A
MOVEECON, #00h; unmap EEPROM
; Restore EA
ret
;*F*************************************************************************
;* NAME: api_wr_eeprom
;* NOTE: before execute this function, be sure the EEPROM is not BUSY
;***************************************************************************
api_wr_eeprom:
; Save and clear EA
MOV
EECON, #050h
MOV
EECON, #0A0h
; Restore EA
ret
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AT/T89C51CC02
Registers
Table 20. EECON Register
EECON (S:0D2h)
EEPROM Control Register
7
6
5
4
3
2
1
0
EEPL3
EEPL2
EEPL1
EEPL0
-
-
EEE
EEBUSY
Bit Number
Bit
Mnemonic
7-4
EEPL3-0
Programming Launch Command bits
Write 5Xh followed by AXh to EEPL to launch the programming.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1
0
EEE
EEBUSY
Description
Enable EEPROM Space bit
Set to map the EEPROM space during MOVX instructions (Write in the column
latches)
Clear to map the XRAM space during MOVX.
Programming Busy Flag
Set by hardware when programming is in progress.
Cleared by hardware when programming is done.
Can not be set or cleared by software.
Reset Value = XXXX XX00b
Not bit addressable
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4126L–CAN–01/08
Program/Code
Memory
The T89C51CC02 implement 16K Bytes of on-chip program/code memory.
The Flash memory increases EPROM and ROM functionality by in-circuit electrical erasure and programming. Thanks to the internal charge pump, the high voltage needed for
programming or erasing Flash cells is generated on-chip using the standard VDD voltage. Thus, the Flash memory can be programmed using only one voltage and allows InSystem Programming (ISP). Hardware programming mode is also available using specific programming tool.
Figure 12. Program/Code Memory Organization
3FFFh
16K Bytes
Internal
Flash
0000h
Flash Memory
Architecture
T89C51CC02 features two on-chip Flash memories:
•
Flash memory FM0:
containing 16K Bytes of program memory (user space) organized into 128 bytes
pages,
•
Flash memory FM1:
2K Bytes for boot loader and Application Programming Interfaces (API).
The FM0 can be program by both parallel programming and Serial ISP whereas FM1
supports only parallel programming by programmers. The ISP mode is detailed in the
’In-System Programming’ section.
All Read/Write access operations on Flash memory by user application are managed by
a set of API described in the ’In-System Programming’ section.
Figure 13. Flash Memory Architecture
2K Bytes
Flash Memory
Boot Space
Hardware Security (1 byte)
Extra Row (128 Bytes)
Column Latches (128 Bytes)
FM1
3FFFh
16K Bytes
FFFFh
F800h
FM1 mapped between F800h and
FFFFh when bit ENBOOT is set in
AUXR1 register
Flash Memory
User Space
FM0
0000h
34
AT/T89C51CC02
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AT/T89C51CC02
FM0 Memory Architecture
The Flash memory is made up of 4 blocks (See Figure 13):
1. The memory array (user space) 16K Bytes
2. The Extra Row
3. The Hardware security bits
4. The column latch registers
User Space
This space is composed of a 16K Bytes Flash memory organized in 128 pages of 128
Bytes. It contains the user’s application code.
Extra Row (XRow)
This row is a part of FM0 and has a size of 128 Bytes. The extra row may contain information for boot loader usage.
Hardware Security Byte
The Hardware security Byte space is a part of FM0 and has a size of 1 byte.
The 4 MSB can be read/written by software, the 4 LSB can only be read by software and
written by hardware in parallel mode.
Column Latches
The column latches, also part of FM0, have a size of full page (128 Bytes).
The column latches are the entrance buffers of the three previous memory locations
(user array, XROW and Hardware security byte).
Cross Flash Memory Access
Description
The FM0 memory can be programmed as describe on Table 21. Programming FM0
from FM0 is impossible.
The FM1 memory can be program only by parallel programming.
Table 21 show all software Flash access allowed.
Code executing from
Table 21. Cross Flash Memory Access
FM0
(user Flash)
FM1
(boot Flash)
Action
FM0
(user Flash)
FM1
(boot Flash)
Read
ok
-
Load column latch
ok
-
Write
-
-
Read
ok
ok
Load column latch
ok
-
Write
ok
-
35
4126L–CAN–01/08
Overview of FM0
Operations
The CPU interfaces the Flash memory through the FCON register and AUXR1 register.
These registers are used to:
•
Map the memory spaces in the adressable space
•
Launch the programming of the memory spaces
•
Get the status of the Flash memory (busy/not busy)
Mapping of the Memory Space By default, the user space is accessed by MOVC instruction for read only. The column
latches space is made accessible by setting the FPS bit in FCON register. Writing is
possible from 0000h to 3FFFh, address bits 6 to 0 are used to select an address within a
page while bits 14 to 7 are used to select the programming address of the page.
Setting FPS bit takes precedence on the EEE bit in EECON register.
The other memory spaces (user, extra row, hardware security) are made accessible in
the code segment by programming bits FMOD0 and FMOD1 in FCON register in accordance with Table 22. A MOVC instruction is then used for reading these spaces.
Table 22. FM0 blocks Select bits
Launching Programming
FMOD1
FMOD0
FM0 Adressable Space
0
0
User (0000h-3FFFh)
0
1
Extra Row(FF80h-FFFFh)
1
0
Hardware Security Byte (0000h)
1
1
Reserved
FPL3:0 bits in FCON register are used to secure the launch of programming. A specific
sequence must be written in these bits to unlock the write protection and to launch the
programming. This sequence is 5xh followed by Axh. Table 23 summarizes the memory
spaces to program according to FMOD1:0 bits.
Table 23. Programming Spaces
Write to FCON
FPL3:0
FPS
FMOD1
FMOD0
Operation
5
x
0
0
No action
A
x
0
0
Write the column latches in user
space
5
x
0
1
No action
A
x
0
1
Write the column latches in extra row
space
5
x
1
0
No action
A
x
1
0
Write the fuse bits space
5
x
1
1
No action
A
x
1
1
No action
User
Extra Row
Hardware
Security
Byte
Reserved
Note:
36
The sequence 5xh and Axh must be executing without instructions between them otherwise the programming is aborted.
Interrupts that may occur during programming time must be disabled to avoid any spurious exit of the programming mode.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Status of the Flash Memory
The bit FBUSY in FCON register is used to indicate the status of programming.
FBUSY is set when programming is in progress.
Selecting FM1
The bit ENBOOT in AUXR1 register is used to map FM1 from F800h to FFFFh.
Loading the Column Latches
Any number of data from 1 byte to 128 Bytes can be loaded in the column latches. This
provides the capability to program the whole memory by byte, by page or by any number
of Bytes in a page.
When programming is launched, an automatic erase of the locations loaded in the column latches is first performed, then programming is effectively done. Thus no page or
block erase is needed and only the loaded data are programmed in the corresponding
page.
The following procedure is used to load the column latches and is summarized in
Figure 14:
•
Save then disable interrupt and map the column latch space by setting FPS bit.
•
Load the DPTR with the address to load.
•
Load Accumulator register with the data to load.
•
Execute the MOVX @DPTR, A instruction.
•
If needed loop the three last instructions until the page is completely loaded.
•
unmap the column latch and Restore Interrupt
37
4126L–CAN–01/08
Figure 14. Column Latches Loading Procedure(1)
Column Latches
Loading
Save & Disable IT
EA = 0
Column Latches Mapping
FCON = 08h (FPS = 1)
Data Load
DPTR = Address
ACC = Data
Exec: MOVX @DPTR, A
Last Byte
to load?
Data Memory Mapping
FCON = 00h (FPS = 0)
Restore IT
Note:
1. The last page address used when loading the column latch is the one used to select
the page programming address.
Programming the Flash Spaces
User
The following procedure is used to program the User space and is summarized in
Figure 15:
Extra Row
38
•
Load up to one page of data in the column latches from address 0000h to 3FFFh.
•
Save then disable the interrupts.
•
Launch the programming by writing the data sequence 50h followed by A0h in
FCON register.This step must be executed from FM1.
The end of the programming indicated by the FBUSY flag cleared.
•
Restore the interrupts.
The following procedure is used to program the Extra Row space and is summarized in
Figure 15:
•
Load data in the column latches from address FF80h to FFFFh.
•
Save then disable the interrupts.
•
Launch the programming by writing the data sequence 52h followed by A2h in
FCON register. This step of the procedure must be executed from FM1.
The end of the programming indicated by the FBUSY flag cleared.
•
Restore the interrupts.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 15. Flash and Extra row Programming Procedure
Flash Spaces
Programming
Column Latches Loading
See Figure 14
Save & Disable IT
EA = 0
Launch Programming
FCON = 5xh
FCON = Axh
FBusy
Cleared?
Clear Mode
FCON = 00h
End Programming
Restore IT
Hardware Security Byte
The following procedure is used to program the Hardware Security Byte space
and is summarized in Figure 16:
•
Set FPS and map Hardware byte (FCON = 0x0C)
•
Save then disable the interrupts.
•
Load DPTR at address 0000h.
•
Load Accumulator register with the data to load.
•
Execute the MOVX @DPTR, A instruction.
•
Launch the programming by writing the data sequence 54h followed by A4h in
FCON register. This step of the procedure must be executed from FM1.
The end of the programming indicated by the FBusy flag cleared.
•
Restore the interrupts
39
4126L–CAN–01/08
Figure 16. Hardware Programming Procedure
Flash Spaces
Programming
Save & Disable IT
EA = 0
Save & Disable IT
EA = 0
FCON = 0Ch
Launch Programming
FCON = 54h
FCON = A4h
Data Load
DPTR = 00h
ACC = Data
Exec: MOVX @DPTR, A
FBusy
Cleared?
End Loading
Restore IT
Clear Mode
FCON = 00h
End Programming
RestoreIT
Reading the Flash Spaces
User
The following procedure is used to read the User space:
•
Read one byte in Accumulator by executing MOVC A,@A+DPTR with A+DPTR is
the address of the code byte to read.
Note:
Extra Row
Hardware Security Byte
40
FCON must be cleared (00h) when not used.
The following procedure is used to read the Extra Row space and is summarized in
Figure 17:
•
Map the Extra Row space by writing 02h in FCON register.
•
Read one byte in Accumulator by executing MOVC A,@A+DPTR with A= 0 &
DPTR= FF80h to FFFFh.
•
Clear FCON to unmap the Extra Row.
The following procedure is used to read the Hardware Security Byte and is summarized in Figure 17:
•
Map the Hardware Security space by writing 04h in FCON register.
•
Read the byte in Accumulator by executing MOVC A,@A+DPTR with A= 0 &
DPTR= 0000h.
•
Clear FCON to unmap the Hardware Security Byte.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 17. Reading Procedure
Flash Spaces Reading
Flash Spaces Mapping
FCON = 00000aa0b
Data Read
DPTR = Address
ACC= 0
Exec: MOVC A, @A+DPTR
Clear Mode
FCON = 00h
Note:
Flash Protection from Parallel
Programming
aa = 10 for the Hardware Security Byte.
The three lock bits in Hardware Security Byte (See ’In-System Programming’ section)
are programmed according to Table 24 provide different level of protection for the onchip code and data located in FM0 and FM1.
The only way to write this bits are the parallel mode. They are set by default to level 3.
Table 24. Program Lock bit
Program Lock bits
Security
Level
LB0
LB1
LB2
1
U
U
U
No program lock features enabled.
2
P
U
U
Parallel programming of the Flash is disabled.
3
U
P
U
Same as 2, also verify through parallel programming interface is
disabled. This is the factory defaul programming.
4
U
U
P
Same as 3
Note:
Protection Description
1. Program Lock bits
U: unprogrammed
P: programmed
WARNING: Security level 2, 3 and 4 should only be programmed after Flash and Core
verification.
Preventing Flash Corruption
See Section “Power Management”.
41
4126L–CAN–01/08
Registers
Table 25. FCON Register
FCON Register FCON (S:D1h)
Flash Control Register
7
6
5
4
3
2
1
0
FPL3
FPL2
FPL1
FPL0
FPS
FMOD1
FMOD0
FBUSY
Bit
Number
Bit
Mnemonic Description
7-4
FPL3:0
3
FPS
2-1
FMOD1:0
0
FBUSY
Programming Launch Command bits
Write 5Xh followed by AXh to launch the programming according to FMOD1:0.
(See Table 23.)
Flash Map Program Space
Set to map the column latch space in the data memory space.
Clear to re-map the data memory space.
Flash Mode
See Table 22 or Table 23.
Flash Busy
Set by hardware when programming is in progress.
Clear by hardware when programming is done.
Can not be changed by software.
Reset Value = 0000 0000b
42
AT/T89C51CC02
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AT/T89C51CC02
43
4126L–CAN–01/08
Operation Cross
Memory Access
Space addressable in read and write are:
•
RAM
•
ERAM (Expanded RAM access by movx)
•
EEPROM DATA
•
FM0 ( user flash )
•
Hardware byte
•
XROW
•
Boot Flash
•
Flash Column latch
The table below provides the different kind of memory which can be accessed from different code location.
Table 26. Cross Memory Access
Hardware
Action
RAM
ERAM
Boot FLASH
FM0
E² Data
Byte
XROW
Read
OK
OK
OK
OK
-
Write
-
OK(1)
OK(1)
OK(1)
OK(1)
Read
OK
OK
OK
-OK
-
Write
-
OK (idle)
OK(1)
-
-OK
boot FLASH
FM0
Note:
44
1. RWW: Read While Write
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Sharing Instructions
Table 27. Instructions shared
Action
RAM
ERAM
EEPROM
DATA
Boot
FLASH
FM0
Hardware
Byte
XROW
Read
MOV
MOVX
MOVX
MOVC
MOVC
MOVC
MOVC
Write
MOV
MOVX
MOVX
-
by cl
by cl
by cl
Note:
by cl : using Column Latch
Table 28. Read MOVX A, @DPTR
Flash
EEE bit in
FPS in
EECON
Register
FCON Register
ENBOOT
ERAM
0
0
X
OK
0
1
X
OK
1
0
X
1
1
X
EEPROM
DATA
Column
Latch
OK
OK
Table 29. Write MOVX @DPTR,A
Flash
EEE bit in
FPS bit in
EECON
Register
FCON Register
ENBOOT
ERAM
0
0
X
OK
0
1
X
1
0
X
1
1
X
EEPROM
Data
Column
Latch
OK
OK
OK
45
4126L–CAN–01/08
Table 30. Read MOVC A, @DPTR
FCON Register
Code Execution FMOD1
0
FMOD0
0
Hardware
FPS
ENBOOT
DPTR
0
0000h to 3FFFh
OK
0000h to 3FFFh
OK
X
FM1
FM0
XROW
Byte
1
F800h to FFFFh
Do not use this configuration
0000 to 007Fh
0
1
X
X
1
0
X
X
X
0
000h to 3FFFh
OK
0000h to 3FFFh
OK
From FM0
1
1
X
OK
See (1)
OK
1
F800h to FFFFh
Do not use this configuration
0000h to 3FFF
OK
1
F800h to FFFFh
0
0
0
0
X
1
X
0
X
1
0000h to 007h
OK
NA
OK
1
From FM1
(ENBOOT =1
0
1
X
0
See
NA
OK
(2)
NA
1
1
0
X
OK
X
0
NA
1
1
1
X
OK
000h to 3FFFh
0
NA
1. For DPTR higher than 007Fh only lowest 7 bits are decoded, thus the behavior is the same as for addresses from
0000h to 007Fh
2. For DPTR higher than 007Fh only lowest 7 bits are decoded, thus the behavior is the same as for addresses from
0000h to 007Fh
46
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
In-System
Programming (ISP)
With the implementation of the User Space (FM0) and the Boot Space (FM1) in Flash
technology the T89C51CC02 allows the system engineer the development of applications with a very high level of flexibility. This flexibility is based on the possibility to alter
the customer program at any stages of a product’s life:
•
Before mounting the chip on the PCB, FM0 flash can be programmed with the
application code. FM1 is always preprogrammed by Atmel with a bootloader (chip
can be ordered with CAN bootloader or UART bootloader).(1)
•
Once the chip is mounted on the PCB, it can be programmed by serial mode via the
CAN bus or UART.
Note:
1. The user can also program his own bootloader in FM1.
This ISP allows code modification over the total lifetime of the product.
Besides the default Bootloaders Atmel provide customers all the needed ApplicationProgramming-Interfaces (API) which are needed for the ISP. The API are located in the
Boot memory.
This allow the customer to have a full use of the 16-Kbyte user memory.
Flash Programming and
Erasure
There are three methods for programming the Flash memory:
•
The Atmel bootloader located in FM1 is activated by the application. Low level API
routines (located in FM1)will be used to program FM0. The interface used for serial
downloading to FM0 is the UART or the CAN. API can be called also by user’s
bootloader located in FM0 at [SBV]00h.
•
A further method exist in activating the Atmel boot loader by hardware activation.
See the Section “Hardware Security Byte”.
•
The FM0 can be programmed also by the parallel mode using a programmer.
Figure 18. Flash Memory Mapping
FFFFh
F800h
2K Bytes IAP
Bootloader
FM1
3FFFh
Custom
Bootloader
FM1 Mapped between F800h and FFFFh
when API Called
[SBV]00h
16K Bytes
Flash Memory
FM0
0000h
47
4126L–CAN–01/08
Boot Process
Software Boot Process
Example
Many algorithms can be used for the software boot process. Below are descriptions of
the different flags and Bytes.
Boot Loader Jump bit (BLJB):
- This bit indicates if on RESET the user wants to jump to this application at address
@0000h on FM0 or execute the boot loader at address @F800h on FM1.
- BLJB = 0 (i.e. bootloader FM1 executed after a reset) is the default Atmel factory programming.
-To read or modify this bit, the APIs are used.
Boot Vector Address (SBV):
- This byte contains the MSB of the user boot loader address in FM0.
- The default value of SBV is FCh (no user boot loader in FM0).
- To read or modify this byte, the APIs are used.
Extra Byte (EB) & Boot Status Byte (BSB):
- These Bytes are reserved for customer use.
- To read or modify these Bytes, the APIs are used.
Figure 19. Hardware Boot Process Algorithm
bit ENBOOT in AUXR1 Register
Is Initialized with BLJB Inverted.
RESET
Hardware
Example, if BLJB=0, ENBOOT
is set (=1) during reset, thus the
bootloader is executed after the
reset.
ENBOOT = 0
PC = 0000h
BLJB == 0
?
Software
ENBOOT = 1
PC = F800h
Application
in FM0
ApplicationProgramming-Interface
Bootloader
in FM1
Several Application Program Interface (API) calls are available for use by an application
program to permit selective erasing and programming of Flash pages. All calls are made
by functions.
All these APIs are described in detail in the following documents on the Atmel web site.
48
–
Datasheet Bootloader CAN T89C51CC02.
–
Datasheet Bootloader UART T89C51CC02.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
XROW Bytes
The EXTRA ROW (XROW) includes 128 bytes. Some of these bytes are used for specific purpose in conjonction with the bootloader.
Table 31. XROW Mapping
Description
Hardware Conditions
Default Value
Address
Copy of the Manufacturer Code
58h
30h
Copy of the Device ID#1: Family code
D7h
31h
Copy of the Device ID#2: Memories size and type
BBh
60h
Copy of the Device ID#3: Name and Revision
FFh
61h
It is possible to force the controller to execute the bootloader after a Reset with hardware conditions.
During the first programming, the user can define a configuration on Port1 that will be
recognized by the chip as the hardware conditions during a Reset. If this condition is
met, the chip will start executing the bootloader at the end of the Reset.
See a detailed description in the applicable Document.
–
Datasheet Bootloader CAN T89C51CC02.
–
Datasheet Bootloader UART T89C51CC02.
49
4126L–CAN–01/08
Hardware Security Byte
Table 32. Hardware Security byte
7
6
5
4
3
2
1
0
X2B
BLJB
-
-
-
LB2
LB1
LB0
Bit
Number
Bit
Mnemonic Description
7
X2B
X2 bit
Set this bit to start in standard mode
Clear this bit to start in X2 Mode.
6
BLJB
Boot Loader Jump bit
- 1: To start the user’s application on next RESET (@0000h) located in FM0,
- 0: To start the boot loader(@F800h) located in FM1.
5-3
-
2-0
LB2:0
Reserved
The value read from these bits are indeterminate.
Lock bits (see Table 22)
After erasing the chip in parallel mode, the default value is : FFh
The erasing in ISP mode (from bootloader) does not modify this byte.
Notes:
50
1. Only the 4 MSB bits can be accessed by software.
2. The 4 LSB bits can only be accessed by parallel mode.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Serial I/O Port
The T89C51CC02 I/O serial port is compatible with the I/O serial port in the 80C52.
It provides both synchronous and asynchronous communication modes. It operates as a
Universal Asynchronous Receiver and Transmitter (UART) in three full-duplex modes
(Modes 1, 2 and 3). Asynchronous transmission and reception can occur simultaneously
and at different baud rates
Serial I/O port includes the following enhancements:
•
Framing error detection
•
Automatic address recognition
Figure 20. Serial I/O Port Block Diagram
IB Bus
Write SBUF
TXD
Read SBUF
SBUF
Receiver
SBUF
Transmitter
Load SBUF
Mode 0 Transmit
Receive
Shift register
RXD
Serial Port
Interrupt Request
RI
TI
SCON reg
Framing Error Detection Framing bit error detection is provided for the three asynchronous modes. To enable the
framing bit error detection feature, set SMOD0 bit in PCON register.
Figure 21. Framing Error Block Diagram
SM0/FE
SM1
SM2
REN
TB8
RB8
TI
RI
Set FE bit if Stop bit is 0 (Framing Error)
SM0 to UART Mode Control
SMOD1 SMOD0
-
POF
GF1
GF0
PD
IDL
To UART Framing Error Control
When this feature is enabled, the receiver checks each incoming data frame for a valid
stop bit. An invalid stop bit may result from noise on the serial lines or from simultaneous
transmission by two CPUs. If a valid stop bit is not found, the Framing Error bit (FE) in
SCON register bit is set.
The software may examine the FE bit after each reception to check for data errors.
Once set, only software or a reset clears the FE bit. Subsequently received frames with
valid stop bits cannot clear the FE bit. When the FE feature is enabled, RI rises on the
stop bit instead of the last data bit (See Figure 22 and Figure 23).
51
4126L–CAN–01/08
Figure 22. UART Timing in Mode 1
RXD
D0
D1
D2
Start
bit
D3
D4
D5
D6
D7
Stop
bit
Data Byte
RI
SMOD0 = x
FE
SMOD0 = 1
Figure 23. UART Timing in Modes 2 and 3
RXD
D0
Start
bit
D1
D2
D3
D4
Data Byte
D5
D6
D7
D8
Ninth Stop
bit
bit
RI
SMOD0 = 0
RI
SMOD0 = 1
FE
SMOD0 = 1
Automatic Address
Recognition
The automatic address recognition feature is enabled when the multiprocessor communication feature is enabled (SM2 bit in SCON register is set).
Implemented in the hardware, automatic address recognition enhances the multiprocessor communication feature by allowing the serial port to examine the address of each
incoming command frame. Only when the serial port recognizes its own address will the
receiver set the RI bit in the SCON register to generate an interrupt. This ensures that
the CPU is not interrupted by command frames addressed to other devices.
If necessary, the user can enable the automatic address recognition feature in mode 1.
In this configuration, the stop bit takes the place of the ninth data bit. bit RI is set only
when the received command frame address matches the device’s address and is terminated by a valid stop bit.
To support automatic address recognition, a device is identified by a given address and
a broadcast address.
Note:
Given Address
The multiprocessor communication and automatic address recognition features cannot
be enabled in mode 0 (i.e. setting SM2 bit in SCON register in mode 0 has no effect).
Each device has an individual address that is specified in the SADDR register; the
SADEN register is a mask byte that contains don’t-care bits (defined by zeros) to form
the device’s given address. The don’t-care bits provide the flexibility to address one or
more slaves at a time. The following example illustrates how a given address is formed.
To address a device by its individual address, the SADEN mask byte must be 1111
1111b.
For example:
SADDR0101 0110b
SADEN1111 1100b
Given0101 01XXb
52
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Here is an example of how to use given addresses to address different slaves:
Slave A:SADDR1111 0001b
SADEN1111 1010b
Given1111 0X0Xb
Slave B:SADDR1111 0011b
SADEN1111 1001b
Given1111 0XX1b
Slave C:SADDR1111 0011b
SADEN1111 1101b
Given1111 00X1b
The SADEN byte is selected so that each slave may be addressed separately.
For slave A, bit 0 (the LSB) is a don’t-care bit; for slaves B and C, bit 0 is a 1. To communicate with slave A only, the master must send an address where bit 0 is clear (e.g.
1111 0000b).
For slave A, bit 1 is a 0; for slaves B and C, bit 1 is a don’t care bit. To communicate with
slaves A and B, but not slave C, the master must send an address with bits 0 and 1 both
set (e.g. 1111 0011b).
To communicate with slaves A, B and C, the master must send an address with bit 0 set,
bit 1 clear, and bit 2 clear (e.g. 1111 0001b).
Broadcast Address
A broadcast address is formed from the logical OR of the SADDR and SADEN registers
with zeros defined as don’t-care bits, e.g.:
SADDR 0101 0110b
SADEN 1111 1100b
SADDR OR SADEN1111 111Xb
The use of don’t-care bits provides flexibility in defining the broadcast address, however
in most applications, a broadcast address is FFh. The following is an example of using
broadcast addresses:
Slave A:SADDR1111 0001b
SADEN1111 1010b
Given1111 1X11b,
Slave B:SADDR1111 0011b
SADEN1111 1001b
Given1111 1X11B,
Slave C:SADDR=1111 0010b
SADEN1111 1101b
Given1111 1111b
For slaves A and B, bit 2 is a don’t care bit; for slave C, bit 2 is set. To communicate with
all of the slaves, the master must send an address FFh. To communicate with slaves A
and B, but not slave C, the master can send and address FBh.
53
4126L–CAN–01/08
Registers
Table 33. SCON Register
SCON (S:98h)
Serial Control Register
7
6
5
4
3
2
1
0
FE/SM0
SM1
SM2
REN
TB8
RB8
TI
RI
Bit
Number
Bit
Mnemonic Description
FE
7
Framing Error bit (SMOD0 = 1)
Clear to reset the error state, not cleared by a valid stop bit.
Set by hardware when an invalid stop bit is detected.
SM0
Serial port Mode bit 0 (SMOD0 = 0)
Refer to SM1 for serial port mode selection.
6
SM1
Serial port Mode bit 1
SM0 SM1 Mode
0
0
Shift Register
0
1
8-bit UART
1
0
9bit UART
1
1
9bit UART
5
SM2
Serial port Mode 2 bit/Multiprocessor Communication Enable bit
Clear to disable multiprocessor communication feature.
Set to enable multiprocessor communication feature in mode 2 and 3.
4
REN
Reception Enable bit
Clear to disable serial reception.
Set to enable serial reception.
3
TB8
Transmitter bit 8/Ninth bit to Transmit in Modes 2 and 3
Clear to transmit a logic 0 in the 9th bit.
Set to transmit a logic 1 in the 9th bit.
2
RB8
Receiver bit 8/Ninth bit Received in Modes 2 and 3
Cleared by hardware if 9th bit received is a logic 0.
Set by hardware if 9th bit received is a logic 1.
1
0
Baud Rate
FXTAL/12 (or FXTAL/6 in mode X2)
Variable
FXTAL/64 or FXTAL/32
Variable
TI
Transmit Interrupt Flag
Clear to acknowledge interrupt.
Set by hardware at the end of the 8th bit time in mode 0 or at the beginning of the
stop bit in the other modes.
RI
Receive Interrupt Flag
Clear to acknowledge interrupt.
Set by hardware at the end of the 8th bit time in mode 0, See Figure 22. and
Figure 23. in the other modes.
Reset Value = 0000 0000b
bit addressable
54
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 34. SADEN Register
SADEN (S:B9h)
Slave Address Mask Register
7
Bit
Number
6
5
4
3
2
1
0
3
2
1
0
3
2
1
0
Bit
Mnemonic Description
7-0
Mask Data for Slave Individual Address
Reset Value = 0000 0000b
Not bit addressable
Table 35. SADDR Register
SADDR (S:A9h)
Slave Address Register
7
Bit
Number
6
5
4
Bit
Mnemonic Description
7-0
Slave Individual Address
Reset Value = 0000 0000b
Not bit addressable
Table 36. SBUF Register
SBUF (S:99h)
Serial Data Buffer
7
Bit
Number
7-0
6
5
4
Bit
Mnemonic Description
Data sent/received by Serial I/O Port
Reset Value = 0000 0000b
Not bit addressable
55
4126L–CAN–01/08
Table 37. PCON Register
PCON (S:87h)
Power Control Register
7
6
5
4
3
2
1
0
SMOD1
SMOD0
-
POF
GF1
GF0
PD
IDL
Bit
Number
Bit
Mnemonic Description
7
SMOD1
Serial port Mode bit 1
Set to select double baud rate in mode 1, 2 or 3.
6
SMOD0
Serial port Mode bit 0
Clear to select SM0 bit in SCON register.
Set to select FE bit in SCON register.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
POF
Power-off Flag
Clear to recognize next reset type.
Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set by
software.
3
GF1
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
2
GF0
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
1
PD
Power-down Mode bit
Cleared by hardware when reset occurs.
Set to enter power-down mode.
0
IDL
Idle Mode bit
Clear by hardware when interrupt or reset occurs.
Set to enter idle mode.
Reset Value = 00X1 0000b
Not bit addressable
56
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Timers/Counters
The T89C51CC02 implements two general-purpose, 16-bit Timers/Counters. Such are
identified as Timer 0 and Timer 1, and can be independently configured to operate in a
variety of modes as a Timer or an event Counter. When operating as a Timer, the
Timer/Counter runs for a programmed length of time, then issues an interrupt request.
When operating as a Counter, the Timer/Counter counts negative transitions on an
external pin. After a preset number of counts, the Counter issues an interrupt request.
The various operating modes of each Timer/Counter are described in the following
sections.
Timer/Counter
Operations
A basic operation is Timer registers THx and TLx (x = 0, 1) connected in cascade to
form a 16-bit Timer. Setting the run control bit (TRx) in TCON register (See Figure 38)
turns the Timer on by allowing the selected input to increment TLx. When TLx overflows
it increments THx; when THx overflows it sets the Timer overflow flag (TFx) in TCON
register. Setting the TRx does not clear the THx and TLx Timer registers. Timer registers can be accessed to obtain the current count or to enter preset values. They can be
read at any time but TRx bit must be cleared to preset their values, otherwise the behavior of the Timer/Counter is unpredictable.
The C/Tx# control bit selects Timer operation or Counter operation by selecting the
divided-down peripheral clock or external pin Tx as the source for the counted signal.
TRx bit must be cleared when changing the mode of operation, otherwise the behavior
of the Timer/Counter is unpredictable.
For Timer operation (C/Tx# = 0), the Timer register counts the divided-down peripheral
clock. The Timer register is incremented once every peripheral cycle (6 peripheral clock
periods). The Timer clock rate is fPER/6, i.e. fOSC/12 in standard mode or fOSC/6 in X2
Mode.
For Counter operation (C/Tx# = 1), the Timer register counts the negative transitions on
the Tx external input pin. The external input is sampled every peripheral cycles. When
the sample is high in one cycle and low in the next one, the Counter is incremented.
Since it takes 2 cycles (12 peripheral clock periods) to recognize a negative transition,
the maximum count rate is fPER/12, i.e. fOSC/24 in standard mode or fOSC/12 in X2 Mode.
There are no restrictions on the duty cycle of the external input signal, but to ensure that
a given level is sampled at least once before it changes, it should be held for at least
one full peripheral cycle.
Timer 0
Timer 0 functions as either a Timer or event Counter in four modes of operation.
Figure 24 through Figure 27 show the logical configuration of each mode.
Timer 0 is controlled by the four lower bits of TMOD register (See Figure 39) and bits 0,
1, 4 and 5 of TCON register (See Figure 38). TMOD register selects the method of
Timer gating (GATE0), Timer or Counter operation (T/C0#) and mode of operation (M10
and M00). TCON register provides Timer 0 control functions: overflow flag (TF0), run
control bit (TR0), interrupt flag (IE0) and interrupt type control bit (IT0).
For normal Timer operation (GATE0 = 0), setting TR0 allows TL0 to be incremented by
the selected input. Setting GATE0 and TR0 allows external pin INT0# to control Timer
operation.
Timer 0 overflow (count rolls over from all 1s to all 0s) sets TF0 flag generating an interrupt request.
It is important to stop Timer/Counter before changing mode.
57
4126L–CAN–01/08
Mode 0 (13-bit Timer)
Mode 0 configures Timer 0 as an 13-bit Timer which is set up as an 8-bit Timer (TH0
register) with a modulo 32 prescaler implemented with the lower five bits of TL0 register
(See Figure 24). The upper three bits of TL0 register are indeterminate and should be
ignored. Prescaler overflow increments TH0 register.
Figure 24. Timer/Counter x (x= 0 or 1) in Mode 0
See section “Clock”
FTx
CLOCK
÷6
0
THx
(8 bits)
1
TLx
(5 bits)
Overflow
TFx
TCON Reg
Tx
Timer x
Interrupt
Request
C/Tx#
TMOD Reg
INTx#
GATEx
TRx
TMOD Reg
TCON Reg
Mode 1 (16-bit Timer)
Mode 1 configures Timer 0 as a 16-bit Timer with TH0 and TL0 registers connected in
cascade (See Figure 25). The selected input increments TL0 register.
Figure 25. Timer/Counter x (x= 0 or 1) in Mode 1
See section “Clock”
FTx
CLOCK
÷6
0
THx
(8 bits)
1
Tx
TLx
(8 bits)
Overflow
TFx
TCON Reg
Timer x
Interrupt
Request
C/Tx#
TMOD Reg
INTx#
GATEx
TMOD Reg
Mode 2 (8-bit Timer with AutoReload)
58
TRx
TCON Reg
Mode 2 configures Timer 0 as an 8-bit Timer (TL0 register) that automatically reloads
from TH0 register (See Figure 26). TL0 overflow sets TF0 flag in TCON register and
reloads TL0 with the contents of TH0, which is preset by software. When the interrupt
request is serviced, hardware clears TF0. The reload leaves TH0 unchanged. The next
reload value may be changed at any time by writing it to TH0 register.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 26. Timer/Counter x (x= 0 or 1) in Mode 2
See section “Clock”
FTx
CLOCK
÷6
0
TLx
(8 bits)
1
Overflow
TFx
TCON Reg
Tx
Timer x
Interrupt
Request
C/Tx#
TMOD Reg
INTx#
GATEx
THx
(8 bits)
TRx
TMOD Reg
TCON Reg
Mode 3 (Two 8-bit Timers)
Mode 3 configures Timer 0 such that registers TL0 and TH0 operate as separate 8-bit
Timers (See Figure 27). This mode is provided for applications requiring an additional 8bit Timer or Counter. TL0 uses the Timer 0 control bits C/T0# and GATE0 in TMOD register, and TR0 and TF0 in TCON register in the normal manner. TH0 is locked into a
Timer function (counting FPER /6) and takes over use of the Timer 1 interrupt (TF1) and
run control (TR1) bits. Thus, operation of Timer 1 is restricted when Timer 0 is in mode
3.
Figure 27. Timer/Counter 0 in Mode 3: Two 8-bit Counters
FTx
CLOCK
÷6
0
1
TL0
(8 bits)
Overflow
TH0
(8 bits)
Overflow
TF0
TCON.5
T0
Timer 0
Interrupt
Request
C/T0#
TMOD.2
INT0#
GATE0
TR0
TMOD.3
FTx
CLOCK
TCON.4
÷6
TCON.7
Timer 1
Interrupt
Request
TR1
See section “Clock”
Timer 1
TF1
TCON.6
Timer 1 is identical to Timer 0 excepted for Mode 3 which is a hold-count mode. Following comments help to understand the differences:
•
Timer 1 functions as either a Timer or event Counter in three modes of operation.
Figure 24 to Figure 26 show the logical configuration for modes 0, 1, and 2. Timer
1’s mode 3 is a hold-count mode.
•
Timer 1 is controlled by the four high-order bits of TMOD register (See Figure 39)
and bits 2, 3, 6 and 7 of TCON register (See Figure 38). TMOD register selects the
method of Timer gating (GATE1), Timer or Counter operation (C/T1#) and mode of
operation (M11 and M01). TCON register provides Timer 1 control functions:
overflow flag (TF1), run control bit (TR1), interrupt flag (IE1) and interrupt type
control bit (IT1).
•
Timer 1 can serve as the Baud Rate Generator for the Serial Port. Mode 2 is best
suited for this purpose.
59
4126L–CAN–01/08
•
For normal Timer operation (GATE1= 0), setting TR1 allows TL1 to be incremented
by the selected input. Setting GATE1 and TR1 allows external pin INT1# to control
Timer operation.
•
Timer 1 overflow (count rolls over from all 1s to all 0s) sets the TF1 flag generating
an interrupt request.
•
When Timer 0 is in mode 3, it uses Timer 1’s overflow flag (TF1) and run control bit
(TR1). For this situation, use Timer 1 only for applications that do not require an
interrupt (such as a Baud Rate Generator for the Serial Port) and switch Timer 1 in
and out of mode 3 to turn it off and on.
•
It is important to stop Timer/Counter before changing mode.
Mode 0 (13-bit Timer)
Mode 0 configures Timer 1 as a 13-bit Timer, which is set up as an 8-bit Timer (TH1 register) with a modulo-32 prescaler implemented with the lower 5 bits of the TL1 register
(See Figure 24). The upper 3 bits of TL1 register are ignored. Prescaler overflow increments TH1 register.
Mode 1 (16-bit Timer)
Mode 1 configures Timer 1 as a 16-bit Timer with TH1 and TL1 registers connected in
cascade (See Figure 25). The selected input increments TL1 register.
Mode 2 (8-bit Timer with AutoReload)
Mode 2 configures Timer 1 as an 8-bit Timer (TL1 register) with automatic reload from
TH1 register on overflow (See Figure 26). TL1 overflow sets TF1 flag in TCON register
and reloads TL1 with the contents of TH1, which is preset by software. The reload
leaves TH1 unchanged.
Mode 3 (Halt)
Placing Timer 1 in mode 3 causes it to halt and hold its count. This can be used to halt
Timer 1 when TR1 run control bit is not available i.e. when Timer 0 is in mode 3.
Interrupt
Each Timer handles one interrupt source that is the timer overflow flag TF0 or TF1. This
flag is set every time an overflow occurs. Flags are cleared when vectoring to the Timer
interrupt routine. Interrupts are enabled by setting ETx bit in IEN0 register. This assumes
interrupts are globally enabled by setting EA bit in IEN0 register.
Figure 28. Timer Interrupt System
Timer 0
Interrupt Request
TF0
TCON.5
ET0
IEN0.1
Timer 1
Interrupt Request
TF1
TCON.7
ET1
IEN0.3
60
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Registers
Table 38. TCON Register
TCON (S:88h)
Timer/Counter Control Register
7
6
5
4
3
2
1
0
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Bit
Number
Bit
Mnemonic Description
7
TF1
Timer 1 Overflow Flag
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 1 register overflows.
6
TR1
Timer 1 Run Control bit
Clear to turn off Timer/Counter 1.
Set to turn on Timer/Counter 1.
5
TF0
Timer 0 Overflow Flag
Cleared by hardware when processor vectors to interrupt routine.
Set by hardware on Timer/Counter overflow, when Timer 0 register overflows.
4
TR0
Timer 0 Run Control bit
Clear to turn off Timer/Counter 0.
Set to turn on Timer/Counter 0.
3
IE1
Interrupt 1 Edge Flag
Cleared by hardware when interrupt is processed if edge-triggered (See IT1).
Set by hardware when external interrupt is detected on INT1# pin.
2
IT1
Interrupt 1 Type Control bit
Clear to select low level active (level triggered) for external interrupt 1 (INT1#).
Set to select falling edge active (edge triggered) for external interrupt 1.
1
IE0
Interrupt 0 Edge Flag
Cleared by hardware when interrupt is processed if edge-triggered (See IT0).
Set by hardware when external interrupt is detected on INT0# pin.
0
IT0
Interrupt 0 Type Control bit
Clear to select low level active (level triggered) for external interrupt 0 (INT0#).
Set to select falling edge active (edge triggered) for external interrupt 0.
Reset Value = 0000 0000b
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4126L–CAN–01/08
Table 39. TMOD Register
TMOD (S:89h)
Timer/Counter Mode Control Register
7
6
5
4
3
2
1
0
GATE1
C/T1#
M11
M01
GATE0
C/T0#
M10
M00
Bit
Number
Bit
Mnemonic Description
7
GATE1
Timer 1 Gating Control bit
Clear to enable Timer 1 whenever TR1 bit is set.
Set to enable Timer 1 only while INT1# pin is high and TR1 bit is set.
6
C/T1#
Timer 1 Counter/Timer Select bit
Clear for Timer operation: Timer 1 counts the divided-down system clock.
Set for Counter operation: Timer 1 counts negative transitions on external pin T1.
5
M11
4
M01
3
GATE0
Timer 0 Gating Control bit
Clear to enable Timer 0 whenever TR0 bit is set.
Set to enable Timer/Counter 0 only while INT0# pin is high and TR0 bit is set.
2
C/T0#
Timer 0 Counter/Timer Select bit
Clear for Timer operation: Timer 0 counts the divided-down system clock.
Set for Counter operation: Timer 0 counts negative transitions on external pin T0.
1
M10
0
M00
Timer 1 Mode Select bits
M11 M01 Operating mode
0
0 Mode 0: 8-bit Timer/Counter (TH1) with 5bit prescaler (TL1).
0
1 Mode 1: 16-bit Timer/Counter.
1
1
1
0
Mode 3: Timer 1 halted. Retains count.
Mode 2: 8-bit auto-reload Timer/Counter (TL1).(1)
Timer 0 Mode Select bit
M10 M00 Operating mode
0
0 Mode 0: 8-bit Timer/Counter (TH0) with 5bit prescaler (TL0).
0
1 Mode 1: 16-bit Timer/Counter.
1
0 Mode 2: 8-bit auto-reload Timer/Counter (TL0).(2)
1
1
Mode 3: TL0 is an 8-bit Timer/Counter.
TH0 is an 8-bit Timer using Timer 1’s TR0 and TF0 bits.
Reset Value = 0000 0000b
Notes:
1. Reloaded from TH1 at overflow.
2. Reloaded from TH0 at overflow.
Table 40. TH0 Register
TH0 (S:8Ch)
Timer 0 High Byte Register
7
Bit
Number
7:0
6
5
4
3
2
1
0
Bit
Mnemonic Description
High Byte of Timer 0
Reset Value = 0000 0000b
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AT/T89C51CC02
Table 41. TL0 Register
TL0 (S:8Ah)
Timer 0 Low Byte Register
7
Bit
Number
6
5
4
3
2
1
0
3
2
1
0
3
2
1
0
Bit
Mnemonic Description
7:0
Low Byte of Timer 0
Reset Value = 0000 0000b
Table 42. TH1 Register
TH1 (S:8Dh)
Timer 1 High Byte Register
7
Bit
Number
6
5
4
Bit
Mnemonic Description
7:0
High Byte of Timer 1
Reset Value = 0000 0000b
Table 43. TL1 Register
TL1 (S:8Bh)
Timer 1 Low Byte Register
7
Bit
Number
7:0
6
5
4
Bit
Mnemonic Description
Low Byte of Timer 1
Reset Value = 0000 0000b
63
4126L–CAN–01/08
Timer 2
The T89C51CC02 Timer 2 is compatible with Timer 2 in the 80C52.
It is a 16-bit timer/counter: the count is maintained by two eightbit timer registers, TH2
and TL2 that are cascade-connected. It is controlled by T2CON register (See Table 45)
and T2MOD register (See Table 46). Timer 2 operation is similar to Timer 0 and Timer
1. C/T2 selects FT2 clock/6 (timer operation) or external pin T2 (counter operation) as
timer clock. Setting TR2 allows TL2 to be incremented by the selected input.
Timer 2 includes the following enhancements:
Auto-Reload Mode
•
Auto-reload mode (up or down counter)
•
Programmable clock-output
The auto-reload mode configures Timer 2 as a 16-bit timer or event counter with automatic reload. This feature is controlled by the DCEN bit in T2MOD register (See Table
45). Setting the DCEN bit enables Timer 2 to count up or down as shown in Figure 29. In
this mode the T2EX pin controls the counting direction.
When T2EX is high, Timer 2 counts up. Timer overflow occurs at FFFFh which sets the
TF2 flag and generates an interrupt request. The overflow also causes the 16-bit value
in RCAP2H and RCAP2L registers to be loaded into the timer registers TH2 and TL2.
When T2EX is low, Timer 2 counts down. Timer underflow occurs when the count in the
timer registers TH2 and TL2 equals the value stored in RCAP2H and RCAP2L registers.
The underflow sets TF2 flag and reloads FFFFh into the timer registers.
The EXF2 bit toggles when Timer 2 overflow or underflow, depending on the direction of
the count. EXF2 does not generate an interrupt. This bit can be used to provide 17-bit
resolution.
Figure 29. Auto-Reload Mode Up/Down Counter
See section “Clock”
FT2
CLOCK
:6
0
1
TR2
T2CON.2
CT/2
T2CON.1
T2
(DOWN COUNTING RELOAD VALUE)
FFh
(8-bit)
FFh
(8-bit)
T2EX:
1=UP
2=DOWN
TOGGLE T2CON Reg
EXF2
TL2
(8-bit)
RCAP2L
(8-bit)
TH2
(8-bit)
TIMER 2
INTERRUPT
T2CON Reg
TF2
RCAP2H
(8-bit)
(UP COUNTING RELOAD VALUE)
64
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4126L–CAN–01/08
AT/T89C51CC02
Programmable ClockOutput
In clock-out mode, Timer 2 operates as a 50%-duty-cycle, programmable clock generator (Figure 30). The input clock increments TL2 at frequency f OSC /2. The timer
repeatedly counts to overflow from a loaded value. At overflow, the contents of RCAP2H
and RCAP2L registers are loaded into TH2 and TL2. In this mode, Timer 2 overflows do
not generate interrupts. The formula gives the clock-out frequency depending on the
system oscillator frequency and the value in the RCAP2H and RCAP2L registers:
FT2clock
Clock – OutFrequency = ----------------------------------------------------------------------------------------4 × ( 65536 – RCAP2H ⁄ RCAP2L )
For a 16 MHz system clock in x1 mode, Timer 2 has a programmable frequency range
of 61 Hz (fOSC/216) to 4 MHz (fOSC/4). The generated clock signal is brought out to T2 pin
(P1.0).
Timer 2 is programmed for the clock-out mode as follows:
•
Set T2OE bit in T2MOD register.
•
Clear C/T2 bit in T2CON register.
•
Determine the 16-bit reload value from the formula and enter it in RCAP2H/RCAP2L
registers.
•
Enter a 16-bit initial value in timer registers TH2/TL2. It can be the same as the
reload value or different depending on the application.
•
To start the timer, set TR2 run control bit in T2CON register.
It is possible to use Timer 2 as a baud rate generator and a clock generator simultaneously. For this configuration, the baud rates and clock frequencies are not
independent since both functions use the values in the RCAP2H and RCAP2L registers.
Figure 30. Clock-Out Mode
TL2
(8-bit)
FT2
CLOCK
TH2
(8-bit)
OVERFLOW
TR2
T2CON.2
RCAP2L RCAP2H
(8-bit)
(8-bit)
Toggle
T2
Q
Q
D
T2OE
T2MOD reg
T2EX
EXF2
EXEN2
T2CON reg
TIMER 2
INTERRUPT
T2CON reg
65
4126L–CAN–01/08
Registers
Table 44. T2CON Register
T2CON (S:C8h)
Timer 2 Control Register
7
6
5
4
3
2
1
0
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2#
CP/RL2#
Bit
Number
7
Bit
Mnemonic Description
TF2
Timer 2 Overflow Flag
TF2 is not set if RCLK=1 or TCLK = 1.
Must be cleared by software.
Set by hardware on Timer 2 overflow.
6
EXF2
Timer 2 External Flag
Set when a capture or a reload is caused by a negative transition on T2EX pin if
EXEN2=1.
Set to cause the CPU to vector to Timer 2 interrupt routine when Timer 2
interrupt is enabled.
Must be cleared by software.
5
RCLK
Receive Clock bit
Clear to use timer 1 overflow as receive clock for serial port in mode 1 or 3.
Set to use Timer 2 overflow as receive clock for serial port in mode 1 or 3.
4
TCLK
Transmit Clock bit
Clear to use timer 1 overflow as transmit clock for serial port in mode 1 or 3.
Set to use Timer 2 overflow as transmit clock for serial port in mode 1 or 3.
3
EXEN2
2
TR2
1
C/T2#
0
CP/RL2#
Timer 2 External Enable bit
Clear to ignore events on T2EX pin for Timer 2 operation.
Set to cause a capture or reload when a negative transition on T2EX pin is
detected, if Timer 2 is not used to clock the serial port.
Timer 2 Run Control bit
Clear to turn off Timer 2.
Set to turn on Timer 2.
Timer/Counter 2 Select bit
Clear for timer operation (input from internal clock system: fOSC).
Set for counter operation (input from T2 input pin).
Timer 2 Capture/Reload bit
If RCLK=1 or TCLK=1, CP/RL2# is ignored and timer is forced to auto-reload on
Timer 2 overflow.
Clear to auto-reload on Timer 2 overflows or negative transitions on T2EX pin if
EXEN2=1.
Set to capture on negative transitions on T2EX pin if EXEN2=1.
Reset Value = 0000 0000b
bit addressable
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AT/T89C51CC02
Table 45. T2MOD Register
T2MOD (S:C9h)
Timer 2 Mode Control Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
T2OE
DCEN
Bit
Number
Bit
Mnemonic Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1
T2OE
Timer 2 Output Enable bit
Clear to program P1.0/T2 as clock input or I/O port.
Set to program P1.0/T2 as clock output.
0
DCEN
Down Counter Enable bit
Clear to disable Timer 2 as up/down counter.
Set to enable Timer 2 as up/down counter.
Reset Value = XXXX XX00b
Not bit addressable
Table 46. TH2 Register
TH2 (S:CDh)
Timer 2 High Byte Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit
Number
7-0
Bit
Mnemonic Description
High Byte of Timer 2
Reset Value = 0000 0000b
Not bit addressable
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4126L–CAN–01/08
Table 47. TL2 Register
TL2 (S:CCh)
Timer 2 Low Byte Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit
Number
Bit
Mnemonic Description
7-0
Low Byte of Timer 2
Reset Value = 0000 0000b
Not bit addressable
Table 48. RCAP2H Register
RCAP2H (S:CBh)
Timer 2 Reload/Capture High Byte Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit
Number
Bit
Mnemonic Description
7-0
High Byte of Timer 2 Reload/Capture.
Reset Value = 0000 0000b
Not bit addressable
Table 49. RCAP2L Register
RCAP2L (S:CAh) Timer 2 Reload/Capture Low Byte Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit
Number
7-0
Bit
Mnemonic Description
Low Byte of Timer 2 Reload/Capture.
Reset Value = 0000 0000b
Not bit addressable
68
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AT/T89C51CC02
Watchdog Timer
T89C51CC02 contains a powerful programmable hardware Watchdog Timer (WDT) that
automatically resets the chip if it software fails to reset the WDT before the selected time
interval has elapsed. It permits large Timeout ranging from 16ms to 2s @fOSC = 12 MHz
in X1 mode.
This WDT consists of a 14-bit counter plus a 7-bit programmable counter, a Watchdog
Timer reset register (WDTRST) and a Watchdog Timer programming (WDTPRG) register. When exiting reset, the WDT is -by default- disable.
To enable the WDT, the user has to write the sequence 1EH and E1H into WDTRST
register with no instruction between the two writes. When the Watchdog Timer is
enabled, it will increment every machine cycle while the oscillator is running and there is
no way to disable the WDT except through reset (either hardware reset or WDT overflow reset). When WDT overflows, it will generate an output RESET pulse at the RST
pin. The RESET pulse duration is 96xTOSC, where TOSC=1/fOSC. To make the best use of
the WDT, it should be serviced in those sections of code that will periodically be executed within the time required to prevent a WDT reset
Note:
When the watchdog is enable it is impossible to change its period.
Figure 31. Watchdog Timer
Decoder
RESET
WR
Control
WDTRST
Enable
14-bit Counter
7-bit Counter
Fwd Clock
WDTPRG
Outputs
-
-
-
-
-
2
1
0
RESET
69
4126L–CAN–01/08
Watchdog Programming
The three lower bits (S0, S1, S2) located into WDTPRG register permit to program the
WDT duration.
Table 50. Machine Cycle Count
S2
S1
S0
Machine Cycle Count
0
0
0
214 - 1
0
0
1
215 - 1
0
1
0
216 - 1
0
1
1
217 - 1
1
0
0
218 - 1
1
0
1
219 - 1
1
1
0
220 - 1
1
1
1
221 - 1
To compute WD Timeout, the following formula is applied:
F osc
FTime – Out = ----------------------------------------------------------------------------WDX2 ∧ X2 14
Svalue
6×2
(2 × 2
)
Note:
Svalue represents the decimal value of (S2 S1 S0)
Find Hereafter computed Timeout values for fOSCXTAL = 12 MHz in X1 mode
Table 51. Timeout Computation
70
S2
S1
S0
fOSC=12 MHz
fOSC=16MHz
fOSC=20 MHz
0
0
0
16.38 ms
12.28 ms
9.82 ms
0
0
1
32.77 ms
24.57 ms
19.66 ms
0
1
0
65.54 ms
49.14 ms
39.32 ms
0
1
1
131.07 ms
98.28 ms
78.64 ms
1
0
0
262.14 ms
196.56 ms
157.28 ms
1
0
1
524.29 ms
393.12 ms
314.56 ms
1
1
0
1.05 s
786.24 ms
629.12 ms
1
1
1
2.10 s
1.57 s
1.25 s
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Watchdog Timer
During Power-down
Mode and Idle
In Power-down mode the oscillator stops, which means the WDT also stops. While in
Power-down mode, the user does not need to service the WDT. There are 2 methods of
exiting Power-down mode: by a hardware reset or via a level activated external interrupt
which is enabled prior to entering Power-down mode. When Power-down is exited with
hardware reset, the watchdog is disabled. Exiting Power-down with an interrupt is significantly different. The interrupt shall be held low long enough for the oscillator to stabilize.
When the interrupt is brought high, the interrupt is serviced. To prevent the WDT from
resetting the device while the interrupt pin is held low, the WDT is not started until the
interrupt is pulled high. It is suggested that the WDT be reset during the interrupt service
for the interrupt used to exit Power-down.
To ensure that the WDT does not overflow within a few states of exiting powerdown, it is
best to reset the WDT just before entering powerdown.
In the Idle mode, the oscillator continues to run. To prevent the WDT from resetting
T89C51CC02 while in Idle mode, the user should always set up a timer that will periodically exit Idle, service the WDT, and re-enter Idle mode.
Register
Table 52. WDTPRG Register
WDTPRG (S:A7h) – Watchdog Timer Duration Programming register
7
6
5
4
3
2
1
0
-
-
-
-
-
S2
S1
S0
Bit
Number
Bit
Mnemonic Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
S2
Watchdog Timer Duration selection bit 2
Work in conjunction with bit 1 and bit 0.
1
S1
Watchdog Timer Duration selection bit 1
Work in conjunction with bit 2 and bit 0.
0
S0
Watchdog Timer Duration selection bit 0
Work in conjunction with bit 1 and bit 2.
Reset Value = XXXX X000b
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Table 53. WDTRST Register
WDTRST (S:A6h Write Only) – Watchdog Timer Enable register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit
Number
7
Bit
Mnemonic Description
-
Watchdog Control Value
Reset Value = 1111 1111b
Note:
72
The WDRST register is used to reset/enable the WDT by writing 1EH then E1H in
sequence without instruction between these two sequences.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
CAN Controller
The CAN Controller provides all the features required to implement the serial communication protocol CAN as defined by BOSCH GmbH. The CAN specification as referred to
by ISO/11898 (2.0A & 2.0B) for high speed and ISO/11519-2 for low speed. The CAN
Controller is able to handle all types of frames (Data, Remote, Error and Overload) and
achieves a bitrate of 1-Mbit/s at 8 MHz1 Crystal frequency in X2 Mode.
Note:
1. At BRP = 1 sampling point will be fixed.
CAN Protocol
The CAN protocol is an international standard defined in the ISO 11898 for high speed
and ISO 11519-2 for low speed.
Principles
CAN is based on a broadcast communication mechanism. This broadcast communication is achieved by using a message oriented transmission protocol. These messages
are identified by using a message identifier. Such a message identifier has to be unique
within the whole network and it defines not only the content but also the priority of the
message.
The priority at which a message is transmitted compared to another less urgent message is specified by the identifier of each message. The priorities are laid down during
system design in the form of corresponding binary values and cannot be changed
dynamically. The identifier with the lowest binary number has the highest priority.
Bus access conflicts are resolved by bit-wise arbitration on the identifiers involved by
each node observing the bus level bit for bit. This happens in accordance with the "wired
and" mechanism, by which the dominant state overwrites the recessive state. The competition for bus allocation is lost by all nodes with recessive transmission and dominant
observation. All the "losers" automatically become receivers of the message with the
highest priority and do not re-attempt transmission until the bus is available again.
Message Formats
The CAN protocol supports two message frame formats, the only essential difference
being in the length of the identifier. The CAN standard frame, also known as CAN 2.0 A,
supports a length of 11 bits for the identifier, and the CAN extended frame, also known
as CAN 2.0 B, supports a length of 29 bits for the identifier.
Can Standard Frame
Figure 32. CAN Standard Frames
Data Frame
Bus Idle
SOF
11-bit identifier
ID10..0
Arbitration
Field
Interframe
Space
RTR IDE r0
4-bit DLC
DLC4..0
15-bit CRC
0 - 8 bytes
Control
Field
Data
Field
CRC
ACK
del. ACK del.
CRC
Field
ACK
Field
7 bits
End of
Frame
Intermission
3 bits
Bus Idle
(Indefinite)
Interframe
Space
Remote Frame
Bus Idle
Interframe
Space
SOF
11-bit identifier
ID10..0
Arbitration
Field
RTR IDE r0
4-bit DLC
DLC4..0
Control
Field
15-bit CRC
CRC
Field
CRC
ACK
del. ACK del.
ACK
Field
7 bits
End of
Frame
Intermission
3 bits
Bus Idle
(Indefinite)
Interframe
Space
A message in the CAN standard frame format begins with the "Start Of Frame (SOF)",
this is followed by the "Arbitration field" which consist of the identifier and the "Remote
Transmission Request (RTR)" bit used to distinguish between the data frame and the
data request frame called remote frame. The following "Control field" contains the "IDentifier Extension (IDE)" bit and the "Data Length Code (DLC)" used to indicate the
73
4126L–CAN–01/08
number of following data bytes in the "Data field". In a remote frame, the DLC contains
the number of requested data bytes. The "Data field" that follows can hold up to 8 data
bytes. The frame integrity is guaranteed by the following "Cyclic Redundant Check
(CRC)" sum. The "ACKnowledge (ACK) field" compromises the ACK slot and the ACK
delimiter. The bit in the ACK slot is sent as a recessive bit and is overwritten as a dominant bit by the receivers which have at this time received the data correctly. Correct
messages are acknowledged by the receivers regardless of the result of the acceptance
test. The end of the message is indicated by "End Of Frame (EOF)". The "Intermission
Frame Space (IFS)" is the minimum number of bits separating consecutive messages. If
there is no following bus access by any node, the bus remains idle.
CAN Extended Frame
Figure 33. CAN Extended Frames
Data Frame
Bus Idle
SOF
11-bit base identifier
IDT28..18
SRR IDE
18-bit identifier extension
ID17..0
RTR r1
Arbitration
Field
Interframe
Space
r0
4-bit DLC
DLC4..0
15-bit CRC
0 - 8 bytes
Control
Field
Data
Field
CRC
ACK
del. ACK del.
CRC
Field
7 bits
ACK
Field
End of
Frame
Intermission Bus Idle
3 bits
(Indefinite)
Interframe
Space
Remote Frame
Bus Idle
SOF
11-bit base identifier
IDT28..18
Interframe
Space
SRR IDE
18-bit identifier extension
ID17..0
Arbitration
Field
RTR r1
r0
Control
Field
4-bit DLC
DLC4..0
15-bit CRC
CRC
Field
CRC
ACK
del. ACK del.
ACK
Field
7 bits
Intermission
3 bits
End of
Frame
Bus Idle
(Indefinite)
Interframe
Space
A message in the CAN extended frame format is likely the same as a message in CAN
standard frame format. The difference is the length of the identifier used. The identifier is
made up of the existing 11-bit identifier (base identifier) and an 18-bit extension (identifier extension). The distinction between CAN standard frame format and CAN extended
frame format is made by using the IDE bit which is transmitted as dominant in case of a
frame in CAN standard frame format, and transmitted as recessive in the other case.
Format Co-existence
As the two formats have to co-exist on one bus, it is laid down which message has
higher priority on the bus in the case of bus access collision with different formats and
the same identifier / base identifier: The message in CAN standard frame format always
has priority over the message in extended format.
There are three different types of CAN modules available:
–
–
–
2.0A - Considers 29 bit ID as an error
2.0B Passive - Ignores 29 bit ID messages
2.0B Active - Handles both 11 and 29 bit ID Messages
Bit Timing
To ensure correct sampling up to the last bit, a CAN node needs to re-synchronize
throughout the entire frame. This is done at the beginning of each message with the falling edge SOF and on each recessive to dominant edge.
Bit Construction
One CAN bit time is specified as four non-overlapping time segments. Each segment is
constructed from an integer multiple of the Time Quantum. The Time Quantum or TQ is
the smallest discrete timing resolution used by a CAN node.
74
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 34. CAN Bit Construction
CAN Frame
(producer)
Transmission Point
(producer)
Nominal CAN Bit Time
Time Quantum
(producer)
Segments
(producer)
SYNC_SEG
PROP_SEG
PHASE_SEG_1
PHASE_SEG_2
propagation
delay
Segments
(consumer)
SYNC_SEG
PROP_SEG
PHASE_SEG_1
PHASE_SEG_2
Sample Point
Synchronization Segment
The first segment is used to synchronize the various bus nodes.
On transmission, at the start of this segment, the current bit level is output. If there is a
bit state change between the previous bit and the current bit, then the bus state change
is expected to occur within this segment by the receiving nodes.
Propagation Time Segment
This segment is used to compensate for signal delays across the network.
This is necessary to compensate for signal propagation delays on the bus line and
through the transceivers of the bus nodes.
Phase Segment 1
Phase Segment 1 is used to compensate for edge phase errors.
This segment may be lengthened during resynchronization.
Sample Point
The sample point is the point of time at which the bus level is read and interpreted as the
value of the respective bit. Its location is at the end of Phase Segment 1 (between the
two Phase Segments).
Phase Segment 2
This segment is also used to compensate for edge phase errors.
This segment may be shortened during resynchronization, but the length has to be at
least as long as the information processing time and may not be more than the length of
Phase Segment 1.
Information Processing Time
It is the time required for the logic to determine the bit level of a sampled bit.
The Information processing Time begins at the sample point, is measured in TQ and is
fixed at 2 TQ for the Atmel CAN. Since Phase Segment 2 also begins at the sample
point and is the last segment in the bit time, Phase Segment 2 minimum shall not be
less than the Information processing Time.
Bit Lengthening
As a result of resynchronization, Phase Segment 1 may be lengthened or Phase Segment 2 may be shortened to compensate for oscillator tolerances. If, for example, the
transmitter oscillator is slower than the receiver oscillator, the next falling edge used for
resynchronization may be delayed. So Phase Segment 1 is lengthened in order to
adjust the sample point and the end of the bit time.
75
4126L–CAN–01/08
Bit Shortening
If, on the other hand, the transmitter oscillator is faster than the receiver one, the next
falling edge used for resynchronization may be too early. So Phase Segment 2 in bit N
is shortened in order to adjust the sample point for bit N+1 and the end of the bit time
Synchronization Jump Width
The limit to the amount of lengthening or shortening of the Phase Segments is set by the
Resynchronization Jump Width.
This segment may not be longer than Phase Segment 2.
Programming the Sample Point
Programming of the sample point allows "tuning" of the characteristics to suit the bus.
Early sampling allows more Time Quanta in the Phase Segment 2 so the Synchronization Jump Width can be programmed to its maximum. This maximum capacity to
shorten or lengthen the bit time decreases the sensitivity to node oscillator tolerances,
so that lower cost oscillators such as ceramic resonators may be used.
Late sampling allows more Time Quanta in the Propagation Time Segment which allows
a poorer bus topology and maximum bus length.
Arbitration
Figure 35. Bus Arbitration
Arbitration lost
node A
TXCAN
Node A loses the bus
Node B wins the bus
node B
TXCAN
CAN bus
SOF ID10 ID9 ID8 ID7 ID6 ID5 ID4 ID3 ID2 ID1 ID0 RTR IDE
---------
The CAN protocol handles bus accesses according to the concept called “Carrier Sense
Multiple Access with Arbitration on Message Priority”.
During transmission, arbitration on the CAN bus can be lost to a competing device with
a higher priority CAN Identifier. This arbitration concept avoids collisions of messages
whose transmission was started by more than one node simultaneously and makes sure
the most important message is sent first without time loss.
The bus access conflict is resolved during the arbitration field mostly over the identifier
value. If a data frame and a remote frame with the same identifier are initiated at the
same time, the data frame prevails over the remote frame (c.f. RTR bit).
Errors
The CAN protocol signals any errors immediately as they occur. Three error detection
mechanisms are implemented at the message level and two at the bit level:
Error at Message Level
•
Cyclic Redundancy Check (CRC)
The CRC safeguards the information in the frame by adding redundant check bits at
the transmission end. At the receiver these bits are re-computed and tested against
the received bits. If they do not agree there has been a CRC error.
•
Frame Check
This mechanism verifies the structure of the transmitted frame by checking the bit
76
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
fields against the fixed format and the frame size. Errors detected by frame checks
are designated "format errors".
Error at Bit Level
•
ACK Errors
As already mentioned frames received are acknowledged by all receivers through
positive acknowledgement. If no acknowledgement is received by the transmitter of
the message an ACK error is indicated.
•
Monitoring
The ability of the transmitter to detect errors is based on the monitoring of bus
signals. Each node which transmits also observes the bus level and thus detects
differences between the bit sent and the bit received. This permits reliable detection
of global errors and errors local to the transmitter.
•
Bit Stuffing
The coding of the individual bits is tested at bit level. The bit representation used by
CAN is "Non Return to Zero (NRZ)" coding, which guarantees maximum efficiency
in bit coding. The synchronization edges are generated by means of bit stuffing.
Error Signalling
If one or more errors are discovered by at least one node using the above mechanisms,
the current transmission is aborted by sending an "error flag". This prevents other nodes
accepting the message and thus ensures the consistency of data throughout the network. After transmission of an erroneous message that has been aborted, the sender
automatically re-attempts transmission.
CAN Controller
Description
The CAN controller accesses are made through SFR.
Several operations are possible by SFR:
•
arithmetic and logic operations, transfers and program control (SFR is accessible by
direct addressing).
•
4 independent message objects are implemented, a pagination system manages
their accesses.
Any message object can be programmed in a reception buffer block (even non-consecutive buffers). For the reception of defined messages one or several receiver message
objects can be masked without participating in the buffer feature. An IT is generated
when the buffer is full. The frames following the buffer-full interrupt will not be taken into
account until at least one of the buffer message objects is re-enabled in reception.
Higher priority of a message object for reception or transmission is given to the lower
message object number.
The programmable 16-bit Timer (CANTIMER) is used to stamp each received and sent
message in the CANSTMP register. This timer starts counting as soon as the CAN controller is enabled by the ENA bit in the CANGCON register.
The Time Trigger Communication (TTC) protocol is supported by the T89C51CC02.
77
4126L–CAN–01/08
Figure 36. CAN Controller Block Diagram
bit
Stuffing /Destuffing
TxDC
RxDC
bit
Timing
Logic
Error
Counter
Rec/Tec
Cyclic
Redundancy Check
Receive
Page
Register
DPR(Mailbox + Registers)
Transmit
Priority
Encoder
µC-Core Interface
Interface
Bus
CAN Controller Mailbox
and Registers
Organization
78
Core
Control
The pagination allows management of the 91 registers including 80(4 x 20) Bytes of
mailbox via 32 SFRs.
All actions on the message object window SFRs apply to the corresponding message
object registers pointed by the message object number find in the Page message object
register (CANPAGE) as illustrate in Figure 37.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 37. CAN Controller Memory Organization
SFRs
On-chip CAN Controller Registers
General Control
General Status
General Interrupt
bit Timing - 1
bit Timing - 2
bit Timing - 3
Enable message object
Enable Interrupt
Enable Interrupt message object
Status Interrupt message object
Timer Control
CANTimer High
CANTimer Low
TimTTC High
TimTTC Low
TEC counter
REC counter
Page message object
(message object number)
(Data offset)
4 Message Objects
message object 0 - Status
message object 0 - Control & DLC
message object Status
message object Control & DLC
Message Data
message object 3 - Status
message object 3 - Control & DLC
Ch.3 - Message Data - byte 0
Ch.0 - Message Data - byte 0
8 Bytes
ID Tag - 1
ID Tag - 2
ID Tag - 3
ID Tag - 4
Ch.0 - ID Tag - 1
Ch.0 - ID Tag - 2
Ch.0 - ID Tag - 3
Ch.0 - ID Tag - 4
ID Mask - 1
ID Mask - 2
ID Mask - 3
ID Mask - 4
Ch.0 - ID Mask- 1
Ch.0 - ID Mask- 2
Ch.0 - ID Mask- 3
Ch.0 - ID Mask - 4
TimStmp High
TimStmp Low
Ch.0 TimStmp High
Ch.0 TimStmp Low
Ch.3 - ID Tag - 1
Ch.3 - ID Tag - 2
Ch.3 - ID Tag - 3
Ch.3 - ID Tag - 4
Ch.3 - ID Mask - 1
Ch.3 - ID Mask - 2
Ch.3 - ID Mask - 3
Ch.3 - ID Mask - 4
Ch.3 TimStmp High
Ch.3 TimStmp Low
message object Window SFRs
79
4126L–CAN–01/08
Working on Message Objects
The Page message object register (CANPAGE) is used to select one of the 4 message
objects. Then, message object Control (CANCONCH) and message object Status
(CANSTCH) are available for this selected message object number in the corresponding
SFRs. A single register (CANMSG) is used for the message. The mailbox pointer is
managed by the Page message object register with an auto-incrementation at the end of
each access. The range of this counter is 8.
Note that the maibox is a pure RAM, dedicated to one message object, without overlap.
In most cases, it is not necessary to transfer the received message into the standard
memory. The message to be transmitted can be built directly in the maibox. Most calculations or tests can be executed in the mailbox area which provide quicker access.
CAN Controller
Management
In order to enable the CAN Controller correctly the following registers have to be
initialized:
•
General Control (CANGCON),
•
bit Timing (CANBT 1, 2 & 3),
•
And for each page of 15 message objects:
–
Message object Control (CANCONCH),
–
Message object Status (CANSTCH).
During operation, the CAN Enable message object registers (CANEN) gives a fast overview of the message objects availability.
The CAN messages can be handled by interrupt or polling modes.
A message object can be configured as follows:
•
Transmit message object
•
Receive message object
•
Receive buffer message object
•
Disable
This configuration is made in the CONCH field of the CANCONCH register (See
Table 54).
When a message object is configured, the corresponding ENCH bit of CANEN register
is set.
Table 54. Configuration for CONCH1:2
CONCH 1
CONCH 2
Type of Message Object
0
0
Disable
0
1
Transmitter
1
0
Receiver
1
1
Receiver buffer
When a Transmitter or Receiver action of a message object is completed, the corresponding ENCH bit of the CANEN register is cleared. In order to re-enable the message
object, it is necessary to re-write the configuration in CANCONCH register.
Non-consecutive message objects can be used for all three types of message objects
(Transmitter, Receiver and Receiver buffer).
80
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AT/T89C51CC02
Buffer Mode
Any message object can be used to define one buffer, including non-consecutive message objects, and with no limitation in number of message objects used up to 4.
Each message object of the buffer must be initialized CONCH2 = 1 and CONCH1 = 1;
Figure 38. Buffer Mode
Block buffer
message object 3
message object 2
message object 1
message object 0
buffer 1
buffer 0
The same acceptance filter must be defined for each message objects of the buffer.
When there is no mask on the identifier or the IDE, all messages are accepted.
A received frame will always be stored in the lowest free message object.
When the flag RxOk is set on one of the buffer message objects, this message object
can then be read by the application. This flag must then be cleared by the software and
the message object re-enabled in buffer reception in order to free the message object.
The OVRBUF flag in the CANGIT register is set when the buffer is full. This flag can
generate an interrupt.
The frames following the buffer-full interrupt will not be stored and no status will be overwritten in the CANSTCH registers involved in the buffer until at least one of the buffer
message objects is re-enabled in reception.
This flag must be cleared by the software in order to acknowledge the interrupt.
IT CAN Management
The different interrupts are:
•
Transmission interrupt
•
Reception interrupt
•
Interrupt on error (bit error, stuff error, crc error, form error, acknowledge error)
•
Interrupt when Buffer receive is full
•
Interrupt on overrun of CAN Timer
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4126L–CAN–01/08
Figure 39. CAN Controller Interrupt Structure
CANGIE.5
ENRX
CANGIE.4 CANGIE.3
ENTX ENERCH
RXOK i
CANSIT
CANSTCH.5
SIT i
TXOK i
CANSTCH.6
CANIE
BERR i
EICH i
CANSTCH.4
i=0
SERR i
CANSTCH.3
CANGIT.7
SIT i
CERR i
i=4
CANSTCH.2
CANIT
FERR i
CANGIE.2
CANSTCH.1
ENBUF
AERR i
IEN1.0
ECAN
CANSTCH.0
CANIT
OVRBUF
CANGIT.4
CANGIE.1
ENERG
SERG
CANGIT.3
CERG
CANGIT.2
FERG
CANGIT.1
IEN1.2
AERG
ETIM
CANGIT.0
OVRIT
OVRTIM
CANGIT.5
To enable a transmission interrupt:
•
Enable General CAN IT in the interrupt system register
•
Enable interrupt by message object, EICHi
•
Enable transmission interrupt, ENTX
To enable a reception interrupt:
•
Enable General CAN IT in the interrupt system register
•
Enable interrupt by message object, EICHi
•
Enable reception interrupt, ENRX
To enable an interrupt on message object error:
•
Enable General CAN IT in the interrupt system register
•
Enable interrupt by message object, EICHi
•
Enable interrupt on error, ENERCH
To enable an interrupt on general error:
82
•
Enable General CAN IT in the interrupt system register
•
Enable interrupt on error, ENERG
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
To enable an interrupt on Buffer-full condition:
•
Enable General CAN IT in the interrupt system register
•
Enable interrupt on Buffer full, ENBUF
To enable an interrupt when Timer overruns:
•
Enable Overrun IT in the interrupt system register
When an interrupt occurs, the corresponding message object bit is set in the SIT
register.
To acknowledge an interrupt, the corresponding CANSTCH bits (RXOK, TXOK,...) or
CANGIT bits (OVRTIM, OVRBUF,...), must be cleared by the software application.
When the CAN node is in transmission and detects a Form Error in its frame, a bit Error
will also be raised. Consequently, two consecutive interrupts can occur, both due to the
same error.
When a message object error occurs and is set in CANSTCH register, no general error
are set in CANGIE register.
83
4126L–CAN–01/08
Bit Timing and Baud
Rate
FSM’s (Finite State Machine) of the CAN channel need to be synchronous to the time
quantum. So, the input clock for bit timing is the clock used into CAN channel FSM’s.
Field and segment abbreviations:
•
BRP: Baud Rate Prescaler.
•
TQ: Time Quantum (output of Baud Rate Prescaler).
•
SYNS: SYNchronization Segment is 1 TQ long.
•
PRS: PRopagation time Segment is programmable to be 1, 2, ..., 8 TQ long.
•
PHS1: PHase Segment 1 is programmable to be 1, 2, ..., 8 TQ long.
•
PHS2: PHase Segment 2 is programmable to be superior or eual to the Information
Processing Time and inferior or equal to TPHS1
•
INFORMATION PROCESSING TIME is 2 TQ.
•
SJW: (Re) Synchronization Jump Width is programmable to be minimum of PHS1
and 4.
The total number of TQ in a bit time has to be programmed at least from 8 to 25.
Figure 40. Sample and Transmission Point
bit Timing
FCAN
CLOCK
Prescaler BRP
System Clock Tscl
Time Quantum
PRS 3bit length
PHS1 3bit length
PHS2 3bit length
SJW 2-bit length
Sample Point
Transmission Point
The baud rate selection is made by Tbit calculation:
Tbit = Tsyns + Tprs + Tphs1 + Tphs2
1. Tsyns = Tscl = (BRP[5..0]+ 1)/Fcan = 1TQ
2. Tprs = (1 to 8) * Tscl = (PRS[2..0]+ 1) * Tscl
3. Tphs1 = (1 to 8) * Tscl = (PHS1[2..0]+ 1) * Tscl
4. Tphs2 = (1 to 8) * Tscl = (PHS2[2..0]+ 1) * Tscl
Tphs2 = Max of (Tphs1 and 2TQ)
5. Tsjw = (1 to 4) * Tscl = (SJW[1..0]+ 1) * Tscl
The total number of Tscl (Time Quanta) in a bit time must be comprised between 8 to
25.
84
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AT/T89C51CC02
Figure 41. General Structure of a bit Period
1/ Fcan
Oscillator
bit Rate Prescaler
Tscl
System Clock
One Nominal bit
Data
Tsyns (*)
Tprs
(1) Phase error ≤ 0
(2) Phase error ≥ 0
(3) Phase error > 0
(4) Phase error < 0
Tphs1 (1)
Tphs2 (2)
Tphs1 + Tsjw (3)
Tphs2 - Tsjw (4)
Tbit
(*) Synchronization Segment: SYNS
Tsyns = 1xTscl (fixed)
Sample Point
Transmission Point
Tbit calculation: Tbit = Tsyns + Tprs + Tphs1 + Tphs2
example of bit timing determination for CAN baudrate of 500 kbit/s:
FOSC = 12 MHz in X1 mode => FCAN = 6MHz
Verify that the CAN baud rate you want is an integer division of FCAN clock.
FCAN/CANbaudrate = 6 MHz/500 kHz = 12
The time quanta TQ must be comprised between 8 and 25: TQ = 12 and BRP = 0
Define the various timing parameters: Tbit = Tsyns + Tprs + Tphs1 + Tphs2 =
12TQ
Tsyns = 1TQ and Tsjw =1TQ => SJW = 0
If we chose a sample point at 66.6% => Tphs2 = 4TQ => PHS2 = 3
Tbit = 12 = 4 + 1 + Tphs1 + Tprs, let us choose Tprs = 3 Tphs1 = 4
PHS1 = 3 and PRS = 2
BRP = 0 so CANBT1 = 00h
SJW = 0 and PRS = 2 so CANBT2 = 04h
PHS2 = 3 and PHS1 = 3 so CANBT3 = 36h
85
4126L–CAN–01/08
Fault Confinement
With respect to fault confinement, a unit may be in one of the three following status:
•
Error active
•
Error passive
•
Bus off
An error active unit takes part in bus communication and can send an active error frame
when the CAN macro detects an error.
An error passive unit cannot send an active error frame. It takes part in bus communication, but when an error is detected, a passive error frame is sent. Also, after a
transmission, an error passive unit will wait before initiating further transmission.
A bus off unit is not allowed to have any influence on the bus.
For fault confinement, two error counters (TEC and REC) are implemented.
See CAN Specification for details on Fault confinement.
Figure 42. Line Error Mode
ERRP = 0
BOFF = 0
TEC>127
or
REC>127
Init.
Error
Active
TEC<127
and
REC<127
Error
Passive
ERRP = 1
BOFF = 0
86
TEC: Transmit Error Counter
REC: Receive Error Counter
128 Occurrences
of
11 Consecutive
Recessive
bit
Bus
Off
TEC>255
ERRP = 0
BOFF = 1
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Acceptance Filter
Upon a reception hit (i.e., a good comparison between the ID+RTR+RB+IDE received
and an ID+RTR+RB+IDE specified while taking the comparison mask into account) the
ID+RTR+RB+IDE received are written over the ID TAG Registers.
ID => IDT0-29
RTR => RTRTAG
RB => RB0-1TAG
IDE => IDE in CANCONCH register
Figure 43. Acceptance Filter Block Diagram
RxDC
Rx Shift Register (internal)
ID & RB
RTR
IDE
13/32
13/32
=
13/32
Write
Enable
13/32
ID TAG Registers (Ch i) & CanConch
ID & RB
RTR IDE
Hit
(Ch i)
1
13/32
ID MSK Registers (Ch i)
ID & RB
RTR
IDE
example:
To accept only ID = 318h in part A.
ID MSK = 111 1111 1111 b
ID TAG = 011 0001 1000 b
87
4126L–CAN–01/08
Data and Remote Frame
Description of the different steps for:
•
Data frame
Node B
message object in transmission 0 1
u u
x 0 0
u u u
0 0
u c
x 1 0
u c u
message object disabled
DA
T
AF
RA
ME
x 0 0
u u u
message object in reception
by CAN controller
0 1
c u
x 1 0
u c u
0 0
u c
x 0 1
u u c
0 0
u c
x 0 1
u u c
message object disabled
x 0 0
u u u
message object disabled
x 1 0
u c u
0 0
c c
RT
R
EN
CH
RP
L
TX V
RXOK
O
K
FR
AM
E
ME
FRA )
TA diate
A
D me
(im
RP
L
TX V
RXOK
O
K
RT
R
EN
C
message object in transmission 1 1
u u
0 1
c u
RE
MO
TE
1 1
u u
1 0 0
u u u
message object in reception
0 1
c u
0 0 0
c u u
message object in transmission
by CAN controller
0 0
u c
0 1 0
c c u
message object disabled
Remote frame
H
•
x 0 1
u u c
RE
MO
TE
FR
AM
E
ME
RA
A F red)
T
DA efer
(d
i
u : modified by user
88
message object in reception
RP
L
TX V
O
RX K
O
K
1 1
u u
message object in reception
by user
x 0 0
u u u
RT
R
EN
CH
message object in transmission
message object disabled
0 1
u u
Remote frame, with automatic reply
RT
R
EN
CH
RP
L
TX V
O
RX K
O
K
•
RT
R
EN
CH
RP
L
TX V
O
RX K
O
K
RT
R
EN
CH
RP
L
TX V
RXOK
O
K
Node A
1 1
u u
0 0 0
u u u
message object in reception
1 0
u c
0 0 1
u u c
message object disabled
0 1
u u
x 0 0
u u u
message object in transmission by user
0 0
u c
x 1 0
u c u
message object disabled
i
c : modified by CAN
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Time Trigger
Communication (TTC)
and Message Stamping
The T89C51CC02 has a programmable 16-bit Timer (CANTIMH&CANTIML) for message stamp and TTC.
This CAN Timer starts after the CAN controller is enabled by the ENA bit in the CANGCON register.
Two modes in the timer are implemented:
•
Time Trigger Communication:
–
Note:
•
Capture of this timer value in the CANTTCH & CANTTCL registers on Start
Of Frame (SOF) or End Of Frame (EOF), depending on the SYNCTTC bit in
the CANGCON register, when the network is configured in TTC by the TTC
bit in the CANGCON register.
In this mode, CAN only sends the frame once, even if an error occurs.
Message Stamping
–
Capture of this timer value in the CANSTMPH & CANSTMPL registers of the
message object which received or sent the frame.
–
All messages can be stamps.
–
The stamping of a received frame occurs when the RxOk flag is set.
–
The stamping of a sent frame occurs when the TxOk flag is set.
The CAN Timer works in a roll-over from FFFFh to 0000h which serves as a time base.
When the timer roll-over from FFFFh to 0000h, an interrupt is generated if the ETIM bit
in the interrupt enable register IEN1 is set.
Figure 44. Block Diagram of CAN Timer
When 0xFFFF to 0x0000
OVRTIM
CANGIT.5
Fcan
CLOCK
÷6
CANTCON
CANGCON.1
ENA
CANGCON.5 CANGCON.4
TTC
SYNCTTC
CANTIMH & CANTIML
TXOK i
SOF on CAN frame
CANSTCH.4
EOF on CAN frame
RXOK i
CANSTCH.5
CANSTMPH & CANSTMPL
CANTTCH & CANTTCL
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4126L–CAN–01/08
CAN Autobaud and
Listening Mode
To activate the Autobaud feature, the AUTOBAUD bit in the CANGCON register must
be set. In this mode, the CAN controller is only listening to the line without acknowledging the received messages. It cannot send any message. The error flags are updated.
The bit timing can be adjusted until no error occurs (good configuration find).
In this mode, the error counters are frozen.
To go back to the standard mode, the AUTOBAUD bit must be cleared.
Figure 45. Autobaud Mode
TxDC
TxDC
AUTOBAUD
CANGCON.3
RxDC
1
RxDC
Routine Examples
0
1. Init of CAN macro
// Reset the CAN macro
CANGCON = 01h;
// Disable CAN interrupts
ECAN
= 0;
ETIM
= 0;
// Init the Mailbox
for num_page =0; num_page <4; num_page++
{
CANPAGE = num_channel << 4;
CANCONCH = 00h
CANSTCH = 00h;
CANIDT1 = 00h;
CANIDT2 = 00h;
CANIDT3 = 00h;
CANIDT4 = 00h;
CANIDM1 = 00h;
CANIDM2 = 00h;
CANIDM3 = 00h;
CANIDM4 = 00h;
for num_data =0; num_data <8; num_data++)
{
CANMSG = 00h;
}
}
// Configure the bit timing
CANBT1 = xxh
CANBT2 = xxh
CANBT3 = xxh
90
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4126L–CAN–01/08
AT/T89C51CC02
// Enable the CAN macro
CANGCON = 02h
2. Configure message object 3 in reception to receive only standard (11bit
identifier) message 100h
// Select the message object 3
CANPAGE = 30h
// Enable the interrupt on this message object
CANIE = 08h
// Clear the status and control register
CANSTCH = 00h
CANCONCH= 00h
// Init the acceptance filter to accept only message 100h in standard mode
CANIDT1 = 20h
CANIDT2 = 00h
CANIDT3 = 00h
CANIDT4 = 00h
CANIDM1 = FFh
CANIDM2 = FFh
CANIDM3 = FFh
CANIDM4 = FFh
// Enable channel in reception
CANCONCH = 88h // enable reception
Note: to enable the CAN interrupt in reception:
EA = 1
ECAN = 1
CANGIE = 20h
3. Send a message on the message object 0
// Select the message object 0
CANPAGE = 00h
// Enable the interrupt on this message object
CANIE = 01h
// Clear the Status register
CANSTCH = 00h;
// load the identifier to send (ex: 555h)
CANIDT1 = AAh;
CANIDT2 = A0h;
// load data to send
CANMSG = 00h
CANMSG = 01h
CANMSG = 02h
CANMSG = 03h
CANMSG = 04h
CANMSG = 05h
CANMSG = 06h
CANMSG = 07h
// configure the control register
CANCONCH = 18h
4. Interrupt routine
// Save the current CANPAGE
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4126L–CAN–01/08
// Find the first message object which generate an interrupt in CANSIT
// Select the corresponding message object
// Analyse the CANSTCH register to identify which kind of interrupt is
generated
// Manage the interrupt
// Clear the status register CANSTCH = 00h;
// if it is not a channel interrupt but a general interrupt
// Manage the general interrupt and clear CANGIT register
// restore the old CANPAGE
92
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AT/T89C51CC02
CAN SFRs
Table 55. SFR Mapping
0/8(1)
1/9
2/A
3/B
F8h
IPL1
xxxx x000
CH
0000 0000
CCAP0H
0000 0000
CCAP1H
0000 0000
F0h
B
0000 0000
ADCLK
xxx0 0000
ADCON
x000 0000
E8h
IEN1
xxxx x000
CCAP0L
0000 0000
CCAP1L
0000 0000
E0h
ACC
0000 0000
D8h
CCON
0000 0000
CMOD
0xxx x000
CCAPM0
x000 0000
D0h
PSW
0000 0000
FCON
0000 0000
EECON
xxxx xx00
C8h
T2CON
0000 0000
T2MOD
xxxx xx00
RCAP2L
0000 0000
C0h
P4
xxxx xx11
B8h
CL
0000 0000
4/C
5/D
ADDL
0000 0000
ADDH
0000 0000
IPH1
xxxx x000
F7h
E7h
CCAPM1
x000 0000
DFh
D7h
TH2
0000 0000
1100 0000
CANIE
1111 0000
CANIDM1
xxxx xxxx
CANIDM2
xxxx xxxx
IPL0
x000 0000
SADEN
0000 0000
CANSIT
xxxx 0000
CANIDT1
xxxx xxxx
B0h
P3
1111 1111
CANPAGE
1100 0000
CANSTCH
xxxx xxxx
CANCONCH
xxxx xxxx
A8h
IEN0
0000 0000
SADDR
0000 0000
CANGSTA
1010 0000
P2
xxxx xx11
CANTCON
0000 0000
AUXR1(2)
xxxx 00x0
98h
SCON
0000 0000
SBUF
0000 0000
90h
P1
1111 1111
88h
TCON
0000 0000
0/8(1)
ADCF
0000 0000
EFh
TL2
0000 0000
80h
7/F
FFh
RCAP2H
0000 0000
A0h
6/E
CANGIE
CANEN
xxxx 0000
CFh
CANIDM3
xxxx xxxx
CANIDM4
xxxx xxxx
C7h
CANIDT2
xxxx xxxx
CANIDT3
xxxx xxxx
CANIDT4
xxxx xxxx
BFh
CANBT1
xxxx xxxx
CANBT2
xxxx xxxx
CANBT3
xxxx xxxx
IPH0
x000 0000
B7h
CANGCON
0000 0000
CANTIML
0000 0000
CANTIMH
0000 0000
CANSTMPL
xxxx xxxx
CANSTMPH
xxxx xxxx
AFh
CANMSG
xxxx xxxx
CANTTCL
0000 0000
CANTTCH
0000 0000
WDTRST
1111 1111
WDTPRG
xxxx x000
A7h
CANGIT
0x00 0000
CANTEC
0000 0000
0000 0000
CANREC
9Fh
97h
TMOD
0000 0000
TL0
0000 0000
TL1
0000 0000
SP
0000 0111
DPL
0000 0000
DPH
0000 0000
1/9
2/A
3/B
TH0
0000 0000
4/C
TH1
0000 0000
5/D
6/E
CKCON
0000 0000
8Fh
PCON
00x1 0000
87h
7/F
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4126L–CAN–01/08
Registers
Table 56. CANGCON Register
CANGCON (S:ABh)
CAN General Control Register
7
6
5
4
3
2
1
0
ABRQ
OVRQ
TTC
SYNCTTC
AUTOBAUD
TEST
ENA
GRES
Bit Number
Bit Mnemonic
Description
ABRQ
Abort Request
Not an auto-resetable bit. A reset of the ENCH bit (message object
control & DLC register) is done for each message object. The
pending transmission communications are immediately aborted but
the on-going communication will be terminated normally, setting
the appropriate status flags, TxOk or RxOk.
6
OVRQ
Overload Frame Request (Initiator).
Auto-resetable bit.
Set to send an overload frame after the next received message.
Cleared by the hardware at the beginning of transmission of the
overload frame.
5
TTC
7
Network in Timer Trigger Communication
set to select node in TTC.
clear to disable TTC features.
4
SYNCTTC
3
AUTOBAUD
Synchronization of TTC
When this bit is set the TTC timer is caught on the last bit of the
End Of Frame.
When this bit is clear the TTC timer is caught on the Start Of
Frame.
This bit is only used in the TTC mode.
AUTOBAUD
set to active listening mode.
Clear to disable listening mode
2
1
0
TEST
Test mode. The test mode is intended for factory testing and not for
customer use.
ENA/STB
Enable/Standby CAN Controller
When this bit is set, it enables the CAN controller and its input
clock.
When this bit is clear, the on-going communication is terminated
normally and the CAN controller state of the machine is frozen (the
ENCH bit of each message object does not change).
In the standby mode, the transmitter constantly provides a
recessive level; the receiver is not activated and the input clock is
stopped in the CAN controller. During the disable mode, the
registers and the mailbox remain accessible.
Note that two clock periods are needed to start the CAN controller
state of the machine.
GRES
General Reset (Software Reset).
Auto-resetable bit. This reset command is ‘ORed’ with the
hardware reset in order to reset the controller. After a reset, the
controller is disabled.
Reset Value = 0000 0000b
94
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Table 57. CANGSTA Register
CANGSTA (S:AAh Read Only)
CAN General Status Register
7
6
5
4
3
2
1
0
-
OVFG
-
TBSY
RBSY
ENFG
BOFF
ERRP
Bit Number
Bit Mnemonic
7
-
Description
Reserved
The values read from this bit is indeterminate. Do not set this bit.
Overload frame flag
This status bit is set by the hardware as long as the produced
overload frame is sent.
This flag does not generate an interrupt
6
OVFG
5
-
Reserved
The values read from this bit is indeterminate. Do not set this bit.
TBSY
Transmitter busy
This status bit is set by the hardware as long as the CAN
transmitter generates a frame (remote, data, overload or error
frame) or an ack field. This bit is also active during an InterFrame
Spacing if a frame must be sent.
This flag does not generate an interrupt.
RBSY
Receiver busy
This status bit is set by the hardware as long as the CAN receiver
acquires or monitors a frame.
This flag does not generate an interrupt.
2
ENFG
Enable on-chip CAN controller flag
Because an enable/disable command is not effective immediately,
this status bit gives the true state of a chosen mode.
This flag does not generate an interrupt.
1
BOFF
Bus off mode
See Figure 42
0
ERRP
Error passive mode
See Figure 42
4
3
Reset Value = x0x0 0000b
95
4126L–CAN–01/08
Table 58. CANGIT Register
CANGIT (S:9Bh)
CAN General Interrupt
7
6
5
4
3
2
1
0
CANIT
-
OVRTIM
OVRBUF
SERG
CERG
FERG
AERG
Bit Number
Description
General interrupt flag(1)
This status bit is the image of all the CAN controller interrupts sent
to the interrupt controller.
It can be used in the case of the polling method.
7
CANIT
6
-
Reserved
The values read from this bit is indeterminate. Do not set this bit.
OVRTIM
Overrun CAN Timer
This status bit is set when the CAN timer switches 0xFFFF to
0x0000.
If the bit ETIM in the IE1 register is set, an interrupt is generated.
Clear this bit in order to reset the interrupt.
4
OVRBUF
Overrun BUFFER
0 - no interrupt.
1 - IT turned on
This bit is set when the buffer is full.
bit resetable by user.
See Figure 39.
3
SERG
Stuff Error General
Detection of more than five consecutive bits with the same polarity.
This flag can generate an interrupt. resetable by user.
CERG
CRC Error General
The receiver performs a CRC check on each destuffed received
message from the start of frame up to the data field.
If this checking does not match with the destuffed CRC field, a
CRC error is set.
This flag can generate an interrupt. resetable by user.
1
FERG
Form Error General
The form error results from one or more violations of the fixed form
in the following bit fields:
CRC delimiter
acknowledgment delimiter
end_of_frame
This flag can generate an interrupt. resetable by user.
0
AERG
Acknowledgment Error General
No detection of the dominant bit in the acknowledge slot.
This flag can generate an interrupt. resetable by user.
5
2
Note:
Bit Mnemonic
1. This field is Read Only.
Reset Value = 0x00 0000b
96
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Table 59. CANTEC Register
CANTEC (S:9Ch Read Only) – CAN Transmit Error Counter
7
6
5
4
3
2
1
0
TEC7
TEC6
TEC5
TEC4
TEC3
TEC2
TEC1
TEC0
Bit Number
Bit Mnemonic
7-0
TEC7:0
Description
Transmit Error Counter
See Figure 42
Reset Value = 00h
Table 60. CANREC Register
CANREC (S:9Dh Read Only) – CAN Reception Error Counter
7
6
5
4
3
2
1
0
REC7
REC6
REC5
REC4
REC3
REC2
REC1
REC0
Bit Number
Bit Mnemonic
7-0
REC7:0
Description
Reception Error Counter
See Figure 42
Reset Value = 00h
97
4126L–CAN–01/08
Table 61. CANGIE Register
CANGIE (S:C1h) – CAN
7
6
5
4
3
2
1
0
-
-
ENRX
ENTX
ENERCH
ENBUF
ENERG
-
Bit Number
Bit Mnemonic
Description
7-6
-
5
ENRX
Enable Receive Interrupt
0 - Disable
1 - Enable
4
ENTX
Enable Transmit Interrupt
0 - Disable
1 - Enable
3
ENERCH
2
ENBUF
Enable BUF Interrupt
0 - Disable
1 - Enable
1
ENERG
Enable General Error Interrupt
0 - Disable
1 - Enable
0
-
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
Enable Message Object Error Interrupt
0 - Disable
1 - Enable
Reserved
The value read from this bit is indeterminate. Do not set this bit.
See Figure 39.
Reset Value = xx00 000xb
98
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Table 62. CANEN Register
CANEN (S:CFh Read Only)
CAN Enable Message Object Registers
7
6
5
4
3
2
1
0
-
-
-
-
ENCH3
ENCH2
ENCH1
ENCH0
Bit Number
Bit Mnemonic
7-4
-
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
ENCH3:0
Enable Message Object
0 - message object is disabled => the message object is free for a
new emission or reception.
1 - message object is enabled.
This bit is resetable by re-writing the CANCONCH of the
corresponding message object.
3-0
Description
Reset Value = xxxx 0000b
Table 63. CANSIT Register
CANSIT (S:BBh Read Only) – CAN Status Interrupt Message Object Registers
7
6
5
4
3
2
1
0
-
-
-
-
SIT3
SIT2
SIT1
SIT0
Bit Number
Bit Mnemonic
7-4
-
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
SIT3:0
Status of Interrupt by Message Object
0 - no interrupt.
1 - IT turned on. Reset when interrupt condition is cleared by user.
SIT3:0 = 0b 0000 1001 -> IT’s on message objects 3 & 0.
See Figure 39.
3-0
Description
Reset Value = xxxx0000b
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Table 64. CANIE Register
CANIE (S:C3h) – CAN Enable Interrupt message object Registers
7
6
5
4
3
2
1
0
-
-
-
-
IECH 3
IECH 2
IECH 1
IECH 0
Bit Number
Bit Mnemonic
Description
7-4
-
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
3-0
IECH3:0
Enable Interrupt by Message Object
0 - disable IT.
1 - enable IT.
IECH3:0 = 0b 0000 1100 -> Enable IT’s of message objects 3 & 2.
Reset Value = xxxx 0000b
Table 65. CANBT1 Register
CANBT1 (S:B4h) – CAN bit Timing Registers 1
7
6
5
4
3
2
1
0
-
BRP 5
BRP 4
BRP 3
BRP 2
BRP 1
BRP 0
-
Bit Number
Bit Mnemonic
7
-
Description
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Baud Rate Prescaler
The period of the CAN controller system clock Tscl is
programmable and determines the individual bit timing.(1)
6-1
BRP5:0
BRP[5..0] + 1
Tscl =
FCAN
0
Note:
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1. The CAN controller bit timing registers must be accessed only if the CAN controller is
disabled with the ENA bit of the CANGCON register set to 0.
See Figure 41.
No default value after reset.
100
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Table 66. CANBT2 Register
CANBT2 (S:B5h) – CAN bit Timing Registers 2
7
6
5
4
3
2
1
0
-
SJW 1
SJW 0
-
PRS 2
PRS 1
PRS 0
-
Bit Number
Bit Mnemonic
7
-
6-5
SJW1:0
Description
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Re-synchronization Jump Width
To compensate for phase shifts between clock oscillators of
different bus controllers, the controller must re-synchronize on any
relevant signal edge of the current transmission.
The synchronization jump width defines the maximum number of
clock cycles. A bit period may be shortened or lengthened by a resynchronization.
Tsjw = Tscl x (SJW [1..0] +1)
4
3-1
-
PRS2:0
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Programming Time Segment
This part of the bit time is used to compensate for the physical
delay times within the network. It is twice the sum of the signal
propagation time on the bus line, the input comparator delay and
the output driver delay.
Tprs = Tscl x (PRS[2..0] + 1)
0
Note:
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1. The CAN controller bit timing registers must be accessed only if the CAN controller is
disabled with the ENA bit of the CANGCON register set to 0.
See Figure 41.
No default value after reset.
101
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Table 67. CANBT3 Register
CANBT3 (S:B6h)
CAN bit Timing Registers 3
7
6
5
4
3
2
1
0
-
PHS2 2
PHS2 1
PHS2 0
PHS1 2
PHS1 1
PHS1 0
SMP
Bit Number
Bit Mnemonic
7
-
Description
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Phase Segment 2
This phase is used to compensate for phase edge errors. This
segment can be shortened by the re-synchronization jump width.
6-4
PHS2 2:0
Tphs2 = Tscl x (PHS2[2..0] + 1)
Phasse segment 2 is the maximum of Phase segment1 and the
Information Processing Time (= 2TQ).
3-1
PHS1 2:0
Phase Segment 1
This phase is used to compensate for phase edge errors. This
segment can be lengthened by the re-synchronization jump width.
Tphs1 = Tscl x (PHS1[2..0] + 1)
0
Note:
SMP
Sample Type
0 - once, at the sample point.
1 - three times, the threefold sampling of the bus is the sample
point and twice over a distance of a 1/2 period of the Tscl. The
result corresponds to the majority decision of the three values.
1. The CAN controller bit timing registers must be accessed only if the CAN controller is
disabled with the ENA bit of the CANGCON register set to 0.
See Figure 41.
No default value after reset.
102
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Table 68. CANPAGE Register
CANPAGE (S:B1h) – CAN Message Object Page Register
7
6
5
4
3
2
1
0
-
-
CHNB 1
CHNB 0
AINC
INDX2
INDX1
INDX0
Bit Number
Bit Mnemonic
7-6
-
5-4
CHNB3:0
3
AINC
2-0
INDX2:0
Description
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
Selection of Message Object Number
The available numbers are: 0 to 3(See Figure 37).
Auto Increment of the Index (Active Low)
0 - auto-increment of the index (default value).
1 - non-auto-increment of the index.
Index
Byte location of the data field for the defined message object (See
Figure 37).
Reset Value = xx00 0000b
Table 69. CANCONCH Register
CANCONCH (S:B3h) – CAN Message Object Control and DLC Register
7
6
5
4
3
2
1
0
CONCH 1
CONCH 0
RPLV
IDE
DLC 3
DLC 2
DLC 1
DLC 0
Bit Number
7-6
Bit Mnemonic
CONCH1:0
5
RPLV
4
IDE
3-0
DLC3:0
Description
Configuration of Message Object
CONCH1 CONCH0
0
0: disable
0
1: Launch transmission
1
0: Enable Reception
1
1: Enable Reception Buffer
NOTE: The user must re-write the configuration to enable the
corresponding bit in the CANEN1:2 registers.
Reply valid
Used in the automatic reply mode after receiving a remote frame
0 - reply not ready.
1 - reply ready & valid.
Identifier Extension
0 - CAN standard rev 2.0 A (ident = 11 bits).
1 - CAN standard rev 2.0 B (ident = 29 bits).
Data Length Code
Number of Bytes in the data field of the message.
The range of DLC is from 0 up to 8.
This value is updated when a frame is received (data or remote
frame).
If the expected DLC differs from the incoming DLC, a warning
appears in the CANSTCH register.
No default value after reset
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Table 70. CANSTCH Register
CANSTCH (S:B2h) – CAN Message Object Status Register
7
6
5
4
3
2
1
0
DLCW
TXOK
RXOK
BERR
SERR
CERR
FERR
AERR
Bit Number
Bit Mnemonic
7
6
5
4
3
2
1
Description
DLCW
Data Length Code Warning
The incoming message does not have the DLC expected.
Whatever the frame type, the DLC field of the CANCONCH register
is updated by the received DLC.
TXOK
Transmit OK
The communication enabled by transmission is completed.
When the controller is ready to send a frame, if two or more
message objects are enabled as producers, the lower index
message object (0 to 13) is supplied first. Must be cleared by
software.
This flag can generate an interrupt.
RXOK
Receive OK
The communication enabled by reception is completed.
In the case of two or more message object reception hits, the lower
index message object (0 to 13) is updated first. Must be cleared by
software.
This flag can generate an interrupt.
BERR
bit Error (only in transmission)
The bit value monitored is different from the bit value sent.
Exceptions:
the monitored recessive bit sent as a dominant bit during the
arbitration field and the acknowledge slot detecting a dominant bit
during the sending of an error frame. Must be cleared by software.
This flag can generate an interrupt.
SERR
Stuff Error
Detection of more than five consecutive bits with the same polarity.
Must be cleared by software.
This flag can generate an interrupt.
CERR
CRC Error
The receiver performs a CRC check on each destuffed received
message from the start of frame up to the data field.
If this checking does not match with the destuffed CRC field, a
CRC error is set. Must be cleared by software.
This flag can generate an interrupt.
FERR
Form Error
The form error results from one or more violations of the fixed form
in the following bit fields:
CRC delimiter
acknowledgment delimiter
end_of_frame
Must be cleared by software.
This flag can generate an interrupt.
0
Note:
AERR
Acknowledgment Error
No detection of the dominant bit in the acknowledge slot. Must be
cleared by software.
This flag can generate an interrupt.
See Figure 39.
No default value after reset.
104
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AT/T89C51CC02
Table 71. CANIDT1 Register for V2.0 part A
CANIDT1 for V2.0 part A (S:BCh) – CAN Identifier Tag Registers 1
7
6
5
4
3
2
1
0
IDT 10
IDT 9
IDT 8
IDT 7
IDT 6
IDT 5
IDT 4
IDT 3
Bit Number
Bit Mnemonic
7-0
IDT10:3
Description
IDentifier Tag Value
See Figure 43.
No default value after reset.
Table 72. CANIDT2 Register for V2.0 part A
CANIDT2 for V2.0 part A (S:BDh) – CAN Identifier Tag Registers 2
7
6
5
4
3
2
1
0
IDT 2
IDT 1
IDT 0
-
-
-
-
-
Bit Number
Bit Mnemonic
7-5
IDT2:0
4-0
-
Description
IDentifier Tag Value
See Figure 43.
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
No default value after reset.
Table 73. CANIDT3 Register for V2.0 part A
CANIDT3 for V2.0 part A (S:BEh) –CAN Identifier Tag Registers 3
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit Number
Bit Mnemonic
7-0
-
Description
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
No default value after reset.
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4126L–CAN–01/08
Table 74. CANIDT1 for V2.0 part A
CANIDT4 for V2.0 part A (S:BFh)
CAN Identifier Tag Registers 4
7
6
5
4
3
2
1
0
-
-
-
-
-
RTRTAG
-
RB0TAG
Bit Number
Bit Mnemonic
7-3
-
2
RTRTAG
1
-
0
RB0TAG
Description
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
Remote transmission request tag value.
Reserved
The values read from this bit are indeterminate. Do not set these
bit.
Reserved bit 0 tag value.
No default value after reset.
Table 75. CANIDT2Register for V2.0 part A
CANIDT1 for V2.0 Part B (S:BCh)
CAN Identifier Tag Registers 1
7
6
5
4
3
2
1
0
IDT 28
IDT 27
IDT 26
IDT 25
IDT 24
IDT 23
IDT 22
IDT 21
Bit Number
Bit Mnemonic
7-0
IDT28:21
Description
IDentifier Tag Value
See Figure 43.
No default value after reset.
Table 76. CANIDT2 Register for V2.0 Part B
CANIDT2 for V2.0 Part B (S:BDh)
CAN Identifier Tag Registers 2
7
6
5
4
3
2
1
0
IDT 20
IDT 19
IDT 18
IDT 17
IDT 16
IDT 15
IDT 14
IDT 13
Bit Number
Bit Mnemonic
7-0
IDT20:13
Description
IDentifier Tag Value
See Figure 43.
No default value after reset.
106
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Table 77. CANIDT3 Register for V2.0 Part B
CANIDT3 for V2.0 Part B (S:BEh)
CAN Identifier Tag Registers 3
7
6
5
4
3
2
1
0
IDT 12
IDT 11
IDT 10
IDT 9
IDT 8
IDT 7
IDT 6
IDT 5
Bit Number
Bit Mnemonic
7-0
IDT12:5
Description
IDentifier Tag Value
See Figure 43.
No default value after reset.
Table 78. CANIDT4 Register for V2.0 Part B
CANIDT4 for V2.0 Part B (S:BFh)
CAN Identifier Tag Registers 4
7
6
5
4
3
2
1
0
IDT 4
IDT 3
IDT 2
IDT 1
IDT 0
RTRTAG
RB1TAG
RB0TAG
Bit Number
Bit Mnemonic
Description
7-3
IDT4:0
2
RTRTAG
Remote Transmission Request Tag Value
1
RB1TAG
Reserved bit 1 tag value.
0
RB0TAG
Reserved bit 0 tag value.
IDentifier Tag Value
See Figure 43.
No default value after reset.
107
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Table 79. CANIDM1 Register for V2.0 part A
CANIDM1 for V2.0 part A (S:C4h)
CAN Identifier Mask Registers 1
7
6
5
4
3
2
1
0
IDMSK 10
IDMSK 9
IDMSK 8
IDMSK 7
IDMSK 6
IDMSK 5
IDMSK 4
IDMSK 3
Bit Number
Bit Mnemonic
7-0
IDTMSK10:3
Description
IDentifier Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
No default value after reset.
Table 80. CANIDM2 Register for V2.0 part A
CANIDM2 for V2.0 part A (S:C5h)
CAN Identifier Mask Registers 2
7
6
5
4
3
2
1
0
IDMSK 2
IDMSK 1
IDMSK 0
-
-
-
-
-
Bit Number
Bit Mnemonic
7-5
IDTMSK2:0
4 -0
-
Description
IDentifier Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
No default value after reset.
Table 81. CANIDM3 Register for V2.0 part A
CANIDM3 for V2.0 part A (S:C6h)
CAN Identifier Mask Registers 3
7
6
5
4
3
2
1
0
-
-
-
-
-
-
-
-
Bit Number
Bit Mnemonic
7-0
-
Description
Reserved
The values read from these bits are indeterminate.
No default value after reset.
108
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Table 82. CANIDM4 Register for V2.0 part A
CANIDM4 for V2.0 part A (S:C7h)
CAN Identifier Mask Registers 4
7
6
5
4
3
2
1
0
-
-
-
-
-
RTRMSK
-
IDEMSK
Bit Number
Bit Mnemonic
7-3
-
2
RTRMSK
1
-
0
IDEMSK
Note:
Description
Reserved
The values read from these bits are indeterminate. Do not set these
bits.
Remote transmission request Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
IDentifier Extension Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
The ID Mask is only used for reception.
No default value after reset.
Table 83. CANIDM1 Register for V2.0 Part B
CANIDM1 for V2.0 Part B (S:C4h)
CAN Identifier Mask Registers 1
7
6
5
4
3
2
1
0
IDMSK 28
IDMSK 27
IDMSK 26
IDMSK 25
IDMSK 24
IDMSK 23
IDMSK 22
IDMSK 21
Bit Number
7-0
Note:
Bit Mnemonic
IDMSK28:21
Description
IDentifier Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
The ID Mask is only used for reception.
No default value after reset.
109
4126L–CAN–01/08
Table 84. CANIDM2 Register for V2.0 Part B
CANIDM2 for V2.0 Part B (S:C5h)
CAN Identifier Mask Registers 2
7
6
5
4
3
2
1
0
IDMSK 20
IDMSK 19
IDMSK 18
IDMSK 17
IDMSK 16
IDMSK 15
IDMSK 14
IDMSK 13
Bit Number
Bit Mnemonic
Description
IDentifier Mask Value(1)
7-0
Note:
IDMSK20:13
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
1. The ID Mask is only used for reception.
No default value after reset.
Table 85. CANIDM3 Register for V2.0 Part B
CANIDM3 for V2.0 Part B (S:C6h)
CAN Identifier Mask Registers 3
7
6
5
4
3
2
1
0
IDMSK 12
IDMSK 11
IDMSK 10
IDMSK 9
IDMSK 8
IDMSK 7
IDMSK 6
IDMSK 5
Bit Number
7-0
Note:
Bit Mnemonic
IDMSK12:5
Description
IDentifier Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
The ID Mask is only used for reception.
No default value after reset.
110
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Table 86. CANIDM4 Register for V2.0 Part B
CANIDM4 for V2.0 Part B (S:C7h)
CAN Identifier Mask Registers 4
7
6
5
4
3
2
1
0
IDMSK 4
IDMSK 3
IDMSK 2
IDMSK 1
IDMSK 0
RTRMSK
-
IDEMSK
Bit Number
Note:
Bit Mnemonic
Description
7-3
IDMSK4:0
IDentifier Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
See Figure 43.
2
RTRMSK
Remote transmission request Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
1
-
0
IDEMSK
Reserved
The value read from this bit is indeterminate. Do not set this bit.
IDentifier Extension Mask Value
0 - comparison true forced.
1 - bit comparison enabled.
The ID Mask is only used for reception.
No default value after reset.
Table 87. CANMSG Register
CANMSG (S:A3h)
CAN Message Data Register
7
6
5
4
3
2
1
0
MSG 7
MSG 6
MSG 5
MSG 4
MSG 3
MSG 2
MSG 1
MSG 0
Bit Number
7-0
Bit Mnemonic
MSG7:0
Description
Message Data
This register contains the mailbox data byte pointed at the page
message object register.
After writing in the page message object register, this byte is equal
to the specified message location (in the mailbox) of the predefined identifier + index. If auto-incrementation is used, at the end
of the data register writing or reading cycle, the mailbox pointer is
auto-incremented. The range of the counting is 8 with no end loop
(0, 1,..., 7, 0,...)
No default value after reset.
111
4126L–CAN–01/08
Table 88. CANTCON Register
CANTCON (S:A1h)
CAN Timer ClockControl
7
6
5
4
3
2
1
0
TPRESC 7
TPRESC 6
TPRESC 5
TPRESC 4
TPRESC 3
TPRESC 2
TPRESC 1
TPRESC 0
Bit Number
Bit Mnemonic
7-0
TPRESC7:0
Description
Timer Prescaler of CAN Timer
This register is a prescaler for the main timer upper counter
range = 0 to 255.
See Figure 44.
Reset Value = 00h
Table 89. CANTIMH Register
CANTIMH (S:ADh)
CAN Timer High
7
6
5
4
3
2
1
0
CANGTIM
15
CANGTIM
14
CANGTIM
13
CANGTIM
12
CANGTIM
11
CANGTIM
10
CANGTIM
9
CANGTIM
8
Bit Number
Bit Mnemonic
Description
7-0
CANGTIM15:8
High byte of Message Timer
See Figure 44.
Reset Value = 0000 0000b
Table 90. CANTIML Register
CANTIML (S:ACh)
CAN Timer Low
7
6
5
4
3
2
1
0
CANGTIM
7
CANGTIM
6
CANGTIM
5
CANGTIM
4
CANGTIM
3
CANGTIM
2
CANGTIM
1
CANGTIM
0
Bit Number
Bit Mnemonic
7-0
CANGTIM7:0
Description
Low byte of Message Timer
See Figure 44.
Reset Value = 0000 0000b
112
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Table 91. CANSTMPH Register
CANSTMPH (S:AFh Read Only)
CAN Stamp Timer High
7
6
5
4
3
2
TIMSTMP
15
TIMSTMP
14
TIMSTMP
13
TIMSTMP
12
TIMSTMP
11
TIMSTMP
10
Bit Number
Bit Mnemonic
Description
7-0
TIMSTMP15:8
High byte of Time Stamp
See Figure 44.
1
0
TIMSTMP 9 TIMSTMP 8
No default value after reset
Table 92. CANSTMPL Register
CANSTMPL (S:AEh Read Only)
CAN Stamp Timer Low
7
6
5
4
3
2
1
0
TIMSTMP 7 TIMSTMP 6 TIMSTMP 5 TIMSTMP 4 TIMSTMP 3 TIMSTMP 2 TIMSTMP 1 TIMSTMP 0
Bit Number
Bit Mnemonic
7-0
TIMSTMP7:0
Description
Low byte of Time Stamp
See Figure 44.
No default value after reset
Table 93. CANTTCH Register
CANTTCH (S:A5h Read Only)
CAN TTC Timer High
7
6
5
4
3
2
1
0
TIMTTC 15
TIMTTC 14
TIMTTC 13
TIMTTC 12
TIMTTC 11
TIMTTC 10
TIMTTC 9
TIMTTC 8
Bit Number
Bit Mnemonic
7-0
TIMTTC15:8
Description
High byte of TTC Timer
See Figure 44.
Reset Value = 0000 0000b
Table 94. CANTTCL Register
CANTTCL (S:A4h Read Only)
CAN TTC Timer Low
7
6
5
4
3
2
1
0
TIMTTC 7
TIMTTC 6
TIMTTC 5
TIMTTC 4
TIMTTC 3
TIMTTC 2
TIMTTC 1
TIMTTC 0
Bit Number
Bit Mnemonic
7-0
TIMTTC7:0
Description
Low Byte of TTC Timer
See Figure 44.
Reset Value = 0000 0000b
113
4126L–CAN–01/08
Programmable
Counter Array (PCA)
The PCA provides more timing capabilities with less CPU intervention than the standard
timer/counters. Its advantages include reduced software overhead and improved accuracy. The PCA consists of a dedicated timer/counter which serves as the time base for
an array of two compare/capture modules. Its clock input can be programmed to count
any of the following signals:
•
PCA clock frequency/6 (See “clock” section)
•
PCA clock frequency/2
•
Timer 0 overflow
•
External input on ECI (P1.2)
Each compare/capture modules can be programmed in any one of the following modes:
•
Rising and/or falling edge capture,
•
Software timer
•
High-speed output
•
Pulse width modulator
When the compare/capture modules are programmed in capture mode, software timer,
or high speed output mode, an interrupt can be generated when the module executes its
function. Both modules and the PCA timer overflow share one interrupt vector.
The PCA timer/counter and compare/capture modules share Port 1 for external I/Os.
These pins are listed below. If the pin is not used for the PCA, it can still be used for
standard I/O.
PCA Timer
114
PCA Component
External I/O Pin
16-bit Counter
P1.2/ECI
16-bit Module 0
P1.3/CEX0
16-bit Module 1
P1.4/CEX1
The PCA timer is a common time base for both modules (See Figure 9). The timer count
source is determined from the CPS1 and CPS0 bits in the CMOD SFR (See Table 8)
and can be programmed to run at:
•
1/6 the PCA clock frequency.
•
1/2 the PCA clock frequency.
•
The Timer 0 overflow.
•
The input on the ECI pin (P1.2).
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 46. PCA Timer/Counter
To PCA
modules
FPca/6
overflow
FPca/2
CH
T0 OVF
It
CL
16-bit up counter
P1.2
CIDL
CPS1 CPS0
ECF
CMOD
0xD9
Idle
CF
CR
CCF1 CCF0
CCON
0xD8
The CMOD register includes three additional bits associated with the PCA.
•
The CIDL bit which allows the PCA to stop during idle mode.
•
The ECF bit which when set causes an interrupt and the PCA overflow flag CF in
CCON register to be set when the PCA timer overflows.
The CCON register contains the run control bit for the PCA and the flags for the PCA
timer and each module.
•
The CR bit must be set to run the PCA. The PCA is shut off by clearing this bit.
•
The CF bit is set when the PCA counter overflows and an interrupt will be generated
if the ECF bit in CMOD register is set. The CF bit can only be cleared by software.
•
The CCF0:1 bits are the flags for the modules (CCF0 for module0...) and are set by
hardware when either a match or a capture occurs. These flags also can be cleared
by software.
115
4126L–CAN–01/08
PCA Modules
Each one of the two compare/capture modules has six possible functions. It can
perform:
•
16-bit Capture, positive-edge triggered
•
16-bit Capture, negative-edge triggered
•
16-bit Capture, both positive and negative-edge triggered
•
16-bit Software Timer
•
16-bit High Speed Output
•
8-bit Pulse Width Modulator.
Each module in the PCA has a special function register associated with it (CCAPM0 for
module 0 ...). The CCAPM0:1 registers contain the bits that control the mode that each
module will operate in.
116
•
The ECCF bit enables the CCF flag in the CCON register to generate an interrupt
when a match or compare occurs in the associated module.
•
The PWM bit enables the pulse width modulation mode.
•
The TOG bit when set causes the CEX output associated with the module to toggle
when there is a match between the PCA counter and the module’s capture/compare
register.
•
The match bit MAT when set will cause the CCFn bit in the CCON register to be set
when there is a match between the PCA counter and the module’s capture/compare
register.
•
The two bits CAPN and CAPP in CCAPMn register determine the edge that a
capture input will be active on. The CAPN bit enables the negative edge, and the
CAPP bit enables the positive edge. If both bits are set both edges will be enabled.
•
The bit ECOM in CCAPM register when set enables the comparator function.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
PCA Interrupt
Figure 47. PCA Interrupt System
CF
CR
CCF1 CCF0
CCON
0xD8
PCA Timer/Counter
Module 0
Module 1
To Interrupt
ECF
ECCFn
CMOD.0
CCAPMn.0
PCA Capture Mode
EC
EA
IEN0.6
IEN0.7
To use one of the PCA modules in capture mode either one or both of the CCAPM bits
CAPN and CAPP for that module must be set. The external CEX input for the module
(on port 1) is sampled for a transition. When a valid transition occurs the PCA hardware
loads the value of the PCA counter registers (CH and CL) into the module’s capture registers (CCAPnL and CCAPnH). If the CCFn bit for the module in the CCON SFR and the
ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated.
Figure 48. PCA Capture Mode
PCA Counter
CH
(8-bits)
CL
(8-bits)
CEXn
n = 0, 1
CCAPnH CCAPnL
PCA
Interrupt
Request
CCFn
CCON Reg
-
0CAPPnCAPNn000ECCFn
0
7
CCAPMn Register (n = 0, 1)
117
4126L–CAN–01/08
16-bit Software Timer
Mode
The PCA modules can be used as software timers by setting both the ECOM and MAT
bits in the modules CCAPMn register. The PCA timer will be compared to the module’s
capture registers and when a match occurs an interrupt will occur if the CCFn (CCON
SFR) and the ECCFn (CCAPMn SFR) bits for the module are both set.
Figure 49. PCA 16-bit Software Timer and High Speed Output Mode
PCA Counter
CH
CL
(8 bits)
(8 bits)
Compare/Capture Module
CCAPnL
CCAPnH
(8 bits)
(8 bits)
Match
Toggle
16-bit Comparator
CEXn
Enable
CCFn
CCON reg
7
“0”
Reset
Write to
CCAPnL
“1”
PCA
Interrupt
Request
ECOMn0 0 MATn TOGn0 ECCFn
0
CCAPMn Register
(n = 0, 1)
For software Timer mode, set ECOMn and MATn.
For high speed output mode, set ECOMn, MATn and TOGn.
Write to CCAPnH
118
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4126L–CAN–01/08
AT/T89C51CC02
High Speed Output Mode In this mode the CEX output (on port 1) associated with the PCA module will toggle
each time a match occurs between the PCA counter and the module’s capture registers.
To activate this mode the TOG, MAT, and ECOM bits in the module’s CCAPMn SFR
must be set.
Figure 50. PCA High Speed Output Mode
CCON
CF
Write to
CCAPnH
CR
CCF1 CCF0
0xD8
Reset
PCA IT
Write to
CCAPnL
“0”
CCAPnH
“1”
CCAPnL
Enable
16 bit comparator
CH
Match
CL
CEXn
PCA counter/timer
ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn
Pulse Width Modulator
Mode
CCAPMn, n = 0 to 1
0xDA to 0xDE
All the PCA modules can be used as PWM outputs. The output frequency depends on
the source for the PCA timer. All the modules will have the same output frequency
because they all share the PCA timer. The duty cycle of each module is independently
variable using the module’s capture register CCAPLn. When the value of the PCA CL
SFR is less than the value in the module’s CCAPLn SFR the output will be low, when it
is equal to or greater than it, the output will be high. When CL overflows from FF to 00,
CCAPLn is reloaded with the value in CCAPHn. the allows the PWM to be updated without glitches. The PWM and ECOM bits in the module’s CCAPMn register must be set to
enable the PWM mode.
119
4126L–CAN–01/08
Figure 51. PCA PWM Mode
CCAPnH
CL rolls over from FFh TO 00h loads
CCAPnH contents into CCAPnL
CCAPnL
“0”
CL < CCAPnL
CL (8 bits)
8-bit
Comparator
CEX
CL >= CCAPnL
“1”
120
ECOMn
PWMn
CCAPMn.6
CCAPMn.1
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
PCA Registers
Table 95. CMOD Register
CMOD (S:D9h)
PCA Counter Mode Register
7
6
5
4
3
2
1
0
CIDL
-
-
-
-
CPS1
CPS0
ECF
Bit Number
Bit
Mnemonic
7
CIDL
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2-1
CPS1:0
0
ECF
Description
PCA Counter Idle Control bit
Clear to let the PCA run during Idle mode.
Set to stop the PCA when Idle mode is invoked.
EWC Count Pulse Select bits
CPS1 CPS0 Clock source
0
0
Internal Clock, FPca/6
0
1
Internal Clock, FPca/2
1
0
Timer 0 overflow
1
1
External clock at ECI/P1.2 pin (Max. Rate = FPca/4)
Enable PCA Counter Overflow Interrupt bit
Clear to disable CF bit in CCON register to generate an interrupt.
Set to enable CF bit in CCON register to generate an interrupt.
Reset Value = 0XXX X000b
121
4126L–CAN–01/08
Table 96. CCON Register
CCON (S:D8h)
PCA Counter Control Register
7
6
5
4
3
2
1
0
CF
CR
-
-
-
-
CCF1
CCF0
Bit Number
Bit Mnemonic
Description
7
CF
PCA Timer/Counter Overflow flag
Set by hardware when the PCA Timer/Counter rolls over. This
generates a PCA interrupt request if the ECF bit in CMOD register
is set.
Must be cleared by software.
6
CR
PCA Timer/Counter Run Control bit
Clear to turn the PCA Timer/Counter off.
Set to turn the PCA Timer/Counter on.
5-2
-
Reserved
The value read from these bist are indeterminate. Do not set these
bits.
CCF1
PCA Module 1 Compare/Capture Flag
Set by hardware when a match or capture occurs. This generates a
PCA interrupt request if the ECCF 1 bit in CCAPM 1 register is set.
Must be cleared by software.
CCF0
PCA Module 0 Compare/Capture Flag
Set by hardware when a match or capture occurs. This generates a
PCA interrupt request if the ECCF 0 bit in CCAPM 0 register is set.
Must be cleared by software.
1
0
Reset Value = 00xx xx00b
122
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AT/T89C51CC02
Table 97. CCAPnH Registers
CCAP0H (S:FAh)
CCAP1H (S:FBh)
PCA High Byte Compare/Capture Module n Register (n=0..1)
7
6
5
4
3
2
1
0
CCAPnH 7
CCAPnH 6
CCAPnH 5
CCAPnH 4
CCAPnH 3
CCAPnH 2
CCAPnH 1
CCAPnH 0
Bit Number
Bit Mnemonic
7:0
CCAPnH 7:0
Description
High byte of EWC-PCA comparison or capture values
Reset Value = 0000 0000b
Table 98. CCAPnL Registers
CCAP0L (S:EAh)
CCAP1L (S:EBh)
PCA Low Byte Compare/Capture Module n Register (n=0..1)
7
6
5
4
3
2
1
0
CCAPnL 7
CCAPnL 6
CCAPnL 5
CCAPnL 4
CCAPnL 3
CCAPnL 2
CCAPnL 1
CCAPnL 0
Bit Number
Bit Mnemonic
7:0
CCAPnL 7:0
Description
Low byte of EWC-PCA comparison or capture values
Reset Value = 0000 0000b
123
4126L–CAN–01/08
Table 99. CCAPMn Registers
CCAPM0 (S:DAh)
CCAPM1 (S:DBh)
PCA Compare/Capture Module n Mode registers (n=0..1)
7
6
5
4
3
2
1
0
-
ECOMn
CAPPn
CAPNn
MATn
TOGn
PWMn
ECCFn
Bit Number
Bit Mnemonic
7
-
Description
Reserved
The Value read from this bit is indeterminate. Do not set this bit.
ECOMn
Enable Compare Mode Module x bit
Clear to disable the Compare function.
Set to enable the Compare function.
The Compare function is used to implement the software Timer, the
high-speed output, the Pulse Width Modulator (PWM) and the
Watchdog Timer (WDT).
CAPPn
Capture Mode (Positive) Module x bit
Clear to disable the Capture function triggered by a positive edge
on CEXx pin.
Set to enable the Capture function triggered by a positive edge on
CEXx pin
4
CAPNn
Capture Mode (Negative) Module x bit
Clear to disable the Capture function triggered by a negative edge
on CEXx pin.
Set to enable the Capture function triggered by a negative edge on
CEXx pin.
3
MATn
Match Module x bit
Set when a match of the PCA Counter with the Compare/Capture
register sets CCFx bit in CCON register, flagging an interrupt.
2
TOGn
Toggle Module x bit
The toggle mode is configured by setting ECOMx, MATx and TOGx
bits.
Set when a match of the PCA Counter with the Compare/Capture
register toggles the CEXx pin.
1
PWMn
Pulse Width Modulation Module x Mode bit
Set to configure the module x as an 8-bit Pulse Width Modulator
with output waveform on CEXx pin.
ECCFn
Enable CCFx Interrupt bit
Clear to disable CCFx bit in CCON register to generate an interrupt
request.
Set to enable CCFx bit in CCON register to generate an interrupt
request.
6
5
0
Reset Value = X000 0000b
124
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AT/T89C51CC02
Table 100. CH Register
CH (S:F9h)
PCA Counter Register High value
7
6
5
4
3
2
1
0
CH 7
CH 6
CH 5
CH 4
CH 3
CH 2
CH 1
CH 0
Bit Number
Bit Mnemonic
7:0
CH 7:0
Description
High byte of Timer/Counter
Reset Value = 0000 00000b
Table 101. CL Register
CL (S:E9h)
PCA counter Register Low value
7
6
5
4
3
2
1
0
CL 7
CL 6
CL 5
CL 4
CL 3
CL 2
CL 1
CL 0
Bit Number
Bit Mnemonic
7:0
CL0 7:0
Description
Low byte of Timer/Counter
Reset Value = 0000 00000b
125
4126L–CAN–01/08
Analog-to-Digital
Converter (ADC)
This section describes the on-chip 10-bit analog-to-digital converter of the
T89C51CC02. Eight ADC channels are available for sampling of the external sources
AN0 to AN7. An analog multiplexer allows the single ADC converter to select one from
the 8 ADC channels as ADC input voltage (ADCIN). ADCIN is converted by the 10-bitcascaded potentiometric ADC.
Two modes of conversion are available:
- Standard conversion (8 bits).
- Precision conversion (10 bits).
For the precision conversion, set bit PSIDLE in ADCON register and start conversion.
The device is in a pseudo-idle mode, the CPU does not run but the peripherals are
always running. This mode allows digital noise to be as low as possible, to ensure high
precision conversion.
For this mode it is necessary to work with end of conversion interrupt, which is the only
way to wake the device up.
If another interrupt occurs during the precision conversion, it will be served only after
this conversion is completed.
Features
ADC Port1 I/O Functions
•
8 channels with multiplexed inputs
•
10-bit cascaded potentiometric ADC
•
Conversion time 16 micro-seconds (typ.)
•
Zero Error (offset) ± 2 LSB max
•
Positive External Reference Voltage Range (VAREF) 2.4 to 3.0-volt (typ.)
•
ADCIN Range 0 to 3-volt
•
Integral non-linearity typical 1 LSB, max. 2 LSB
•
Differential non-linearity typical 0.5 LSB, max. 1 LSB
•
Conversion Complete Flag or Conversion Complete Interrupt
•
Selectable ADC Clock
Port 1 pins are general I/O that are shared with the ADC channels. The channel select
bit in ADCF register define which ADC channel/port1 pin will be used as ADCIN. The
remaining ADC channels/port1 pins can be used as general purpose I/O or as the alternate function that is available.
A conversion launched on a channel which are not selected on ADCF register will not
have any effect.
VAREF
VAREF should be connected to a low impedance point and must remain in the range
specified VAREF absolute maximum range (See section “AC-DC”).
. If the ADC is not used, it is recommended to tie VAREF to VAGND.
126
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4126L–CAN–01/08
AT/T89C51CC02
Figure 52. ADC Description
ADCON.5
ADCON.3
ADEN
ADSST
ADC
Interrupt
Request
ADCON.4
ADEOC
ADC
CLOCK
CONTROL
EADC
AN0/P1.0
000
AN1/P1.1
001
AN2/P1.2
010
AN3/P1.3
011
AN4/P1.4
100
AN5/P1.5
101
AN6/P1.6
110
AN7/P1.7
IEN1.1
ADCIN
Rai
SAR
Cai
AVSS
ADDH
2
ADDL
-
Sample and Hold
111
8
+
10
R/2R DAC
SCH2
SCH1
SCH0
ADCON.2
ADCON.1
ADCON.0
VAREF VAGND
Figure 53 shows the timing diagram of a complete conversion. For simplicity, the figure
depicts the waveforms in idealized form and do not provide precise timing information.
For ADC characteristics and timing parameters refer to the section “AC Characteristics”
of this datasheet.
Figure 53. Timing Diagram
CLK
ADEN
TSETUP
ADSST
TCONV
ADEOC
Note:
Tsetup min, see the AC Parameter for A/D conversion.
Tconv = 11 clock ADC = 1sample and hold + 10-bit conversion
The user must ensure that Tsetup time between setting ADEN and the start of the first conversion.
ADC Converter
Operation
A start of single A/D conversion is triggered by setting bit ADSST (ADCON.3).
After completion of the A/D conversion, the ADSST bit is cleared by hardware.
The end-of-conversion flag ADEOC (ADCON.4) is set when the value of conversion is
available in ADDH and ADDL, it must be cleared by software. If the bit EADC (IEN1.1) is
set, an interrupt occur when flag ADEOC is set (See Figure 55). Clear this flag for rearming the interrupt.
Note:
Always leave Tsetup time before starting a conversion unless ADEN is permanently
high. In this case one should wait Tsetup only before the first conversion
127
4126L–CAN–01/08
The bits SCH0 to SCH2 in ADCON register are used for the analog input channel
selection.
Table 102. Selected Analog input
Voltage Conversion
SCH2
SCH1
SCH0
Selected Analog Input
0
0
0
AN0
0
0
1
AN1
0
1
0
AN2
0
1
1
AN3
1
0
0
AN4
1
0
1
AN5
1
1
0
AN6
1
1
1
AN7
When the ADCIN is equals to VAREF the ADC converts the signal to 3FFh (full scale). If
the input voltage equals VAGND, the ADC converts it to 000h. Input voltage between
VAREF and VAGND are a straight-line linear conversion. All other voltages will result in
3FFh if greater than VAREF and 000h if less than VAGND.
Note that ADCIN should not exceed VAREF absolute maximum range (See section
“AC-DC”).
Clock Selection
The ADC clock is the same as CPU.
The maximum clock frequency is defined in the DC parmeter for A/D converter. A prescaler is featured (ADCCLK) to generate the ADC clock from the oscillator frequency.
if PRS = 0 then FADC = Fperiph / 64
if PRS > 0 then FADC = Fperiph / 2 x PRS
Figure 54. A/D Converter Clock
CPU
CLOCK
÷2
CPU Core Clock Symbol
ADC Standby Mode
128
Prescaler ADCLK
ADC Clock
A/D
Converter
When the ADC is not used, it is possible to set it in standby mode by clearing bit ADEN
in ADCON register. In this mode the power dissipation is reduced.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
IT ADC Management
An interrupt end-of-conversion will occurs when the bit ADEOC is activated and the bit
EADC is set. For re-arming the interrupt the bit ADEOC must be cleared by software.
Figure 55. ADC interrupt structure
ADCI
ADEOC
ADCON.2
EADC
IEN1.1
Routine Examples
1. Configure P1.2 and P1.3 in ADC channels
// configure channel P1.2 and P1.3 for ADC
ADCF = 0Ch
// Enable the ADC
ADCON = 20h
2. Start a standard conversion
// The variable ’channel’ contains the channel to convert
// The variable ’value_converted’ is an unsigned int
// Clear the field SCH[2:0]
ADCON &= F8h
// Select channel
ADCON |= channel
// Start conversion in standard mode
ADCON |= 08h
// Wait flag End of conversion
while((ADCON & 01h)!= 01h)
// Clear the End of conversion flag
ADCON &= EFh
// read the value
value_converted = (ADDH << 2)+(ADDL)
3. Start a precision conversion (need interrupt ADC)
// The variable ’channel’ contains the channel to convert
// Enable ADC
EADC = 1
// clear the field SCH[2:0]
ADCON &= F8h
// Select the channel
ADCON |= channel
// Start conversion in precision mode
ADCON |= 48h
Note:
To enable the ADC interrupt: EA = 1
129
4126L–CAN–01/08
Registers
Table 103. ADCF Register
ADCF (S:F6h)
ADC Configuration
7
6
5
4
3
2
1
0
CH 7
CH 6
CH 5
CH 4
CH 3
CH 2
CH 1
CH 0
Bit
Number
7-0
Bit
Mnemonic Description
CH 0:7
Channel Configuration
Set to use P1.x as ADC input.
Clear to use P1.x as standart I/O port.
Reset Value = 0000 0000b
Table 104. ADCON Register
ADCON (S:F3h)
ADC Control Register
7
6
5
4
3
2
1
0
-
PSIDLE
ADEN
ADEOC
ADSST
SCH2
SCH1
SCH0
Bit
Number
Bit
Mnemonic Description
Reserved
The value read from these bits are indeterminate. Do not set these bits.
7
-
6
PSIDLE
5
ADEN
4
ADEOC
End Of Conversion
Set by hardware when ADC result is ready to be read. This flag can generate an
interrupt.
Must be cleared by software.
3
ADSST
Start and Status
Set to start an A/D conversion.
Cleared by hardware after completion of the conversion
2-0
SCH2:0
Selection of Channel to Convert
See Table 102
Pseudo Idle Mode (Best Precision)
Set to put in idle mode during conversion
Clear to convert without idle mode.
Enable/Standby Mode
Set to enable ADC
Clear for Standby mode.
Reset Value = X000 0000b
130
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 105. ADCLK Register
ADCLK (S:F2h)
ADC Clock Prescaler
7
6
5
4
3
2
1
0
-
-
-
PRS 4
PRS 3
PRS 2
PRS 1
PRS 0
Bit
Number
Bit
Mnemonic Description
7-5
-
4-0
PRS4:0
Reserved
The value read from these bits are indeterminate. Do not set these bits.
Clock Prescaler
Fadc = Fcpuclock/(4*PRS)) in X1 mode
Fadc=Fcpuclock/(2*PRS) in X2 mode
Reset Value = XXX0 0000b
Table 106. ADDH Register
ADDH (S:F5h Read Only)
ADC Data High Byte Register
7
6
5
4
3
2
1
0
ADAT 9
ADAT 8
ADAT 7
ADAT 6
ADAT 5
ADAT 4
ADAT 3
ADAT 2
Bit
Number
7-0
Bit
Mnemonic Description
ADAT9:2
ADC result
bits 9-2
Reset Value = 00h
Table 107. ADDL Register
ADDL (S:F4h Read Only)
ADC Data Low Byte Register
7
6
5
4
3
2
1
0
-
-
-
-
-
-
ADAT 1
ADAT 0
Bit
Number
Bit
Mnemonic Description
7-2
-
1-0
ADAT1:0
Reserved
The value read from these bits are indeterminate. Do not set these bits.
ADC result
bits 1-0
Reset Value = 00h
131
4126L–CAN–01/08
Interrupt System
Introduction
The CAN Controller has a total of 10 interrupt vectors: two external interrupts (INT0 and
INT1), three timer interrupts (timers 0, 1 and 2), a serial port interrupt, a PCA, a CAN
interrupt, a timer overrun interrupt and an ADC. These interrupts are shown below.
Figure 56. Interrupt Control System
INT0#
00
01
10
11
External
Interrupt 0
Highest
Priority
Interrupts
EX0
00
01
10
11
IEN0.0
Timer 0
ET0
INT1#
External
Interrupt 1
00
01
10
11
IEN0.1
EX1
00
01
10
11
IEN0.2
Timer 1
ET1
CEX0:1
PCA
00
01
10
11
IEN0.3
EC
TxD
UART
00
01
10
11
IEN0.6
RxD
ES
IEN0.4
00
01
10
11
Timer 2
ET2
IEN0.5
TxDC
RxDC
00
01
10
11
CAN
Controller
ECAN
IEN1.0
AIN1:0
00
01
10
11
A to D
Converter
EADC
00
01
10
11
IEN1.1
CAN Timer
ETIM
EA
IEN1.2
IEN0.7
Interrupt Enable
132
IPH/L
Priority Enable
Lowest Priority Interrupts
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Each of the interrupt sources can be individually enabled or disabled by setting or clearing a bit in the Interrupt Enable register. This register also contains a global disable bit
which must be cleared to disable all the interrupts at the same time.
Each interrupt source can also be individually programmed to one of four priority levels
by setting or clearing a bit in the Interrupt Priority registers. The Table below shows the
bit values and priority levels associated with each combination.
Table 108. Priority Level bit Values
IPH.x
IPL.x
Interrupt Level Priority
0
0
0 (Lowest)
0
1
1
1
0
2
1
1
3 (Highest)
A low-priority interrupt can be interrupted by a high priority interrupt but not by another
low-priority interrupt. A high-priority interrupt cannot be interrupted by any other interrupt
source.
If two interrupt requests of different priority levels are received simultaneously, the
request of the higher priority level is serviced. If interrupt requests of the same priority
level are received simultaneously, an internal polling sequence determines which
request is serviced. Thus within each priority level there is a second priority structure
determined by the polling sequence, See Table 109.
Table 109. Interrupt Priority Within Level
Interrupt Name
Interrupt Address Vector
Interrupt Number
Polling Priority
External interrupt (INT0)
0003h
1
1
Timer0 (TF0)
000Bh
2
2
External interrupt (INT1)
0013h
3
3
Timer 1 (TF1)
001Bh
4
4
PCA (CF or CCFn)
0033h
7
5
UART (RI or TI)
0023h
5
6
Timer 2 (TF2)
002Bh
6
7
CAN (Txok, Rxok, Err or OvrBuf)
003Bh
8
8
ADC (ADCI)
0043h
9
9
CAN Timer Overflow (OVRTIM)
004Bh
10
10
133
4126L–CAN–01/08
Registers
Figure 57. IEN0 Register
IEN0 (S:A8h)
Interrupt Enable Register
7
6
5
4
3
2
1
0
EA
EC
ET2
ES
ET1
EX1
ET0
EX0
Bit
Number
Bit
Mnemonic Description
7
EA
Enable All Interrupt bit
Clear to disable all interrupts.
Set to enable all interrupts.
If EA=1, each interrupt source is individually enabled or disabled by setting or
clearing its interrupt enable bit.
6
EC
PCA Interrupt Enable
Clear to disable the PCA interrupt.
Set to enable the PCA interrupt.
5
ET2
Timer 2 Overflow Interrupt Enable bit
Clear to disable Timer 2 overflow interrupt.
Set to enable Timer 2 overflow interrupt.
4
ES
Serial port Enable bit
Clear to disable serial port interrupt.
Set to enable serial port interrupt.
3
ET1
Timer 1 Overflow Interrupt Enable bit
Clear to disable timer 1 overflow interrupt.
Set to enable timer 1 overflow interrupt.
2
EX1
External Interrupt 1 Enable bit
Clear to disable external interrupt 1.
Set to enable external interrupt 1.
1
ET0
Timer 0 Overflow Interrupt Enable bit
Clear to disable timer 0 overflow interrupt.
Set to enable timer 0 overflow interrupt.
0
EX0
External Interrupt 0 Enable bit
Clear to disable external interrupt 0.
Set to enable external interrupt 0.
Reset Value = 0000 0000b
bit addressable
134
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Figure 58. IEN1 Register
IEN1 (S:E8h)
Interrupt Enable Register
7
6
5
4
-
-
-
-
Bit
Number
3
2
1
0
ETIM
EADC
ECAN
Bit
Mnemonic Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
ETIM
TImer overrun Interrupt Enable bit
Clear to disable the timer overrun interrupt.
Set to enable the timer overrun interrupt.
1
EADC
ADC Interrupt Enable bit
Clear to disable the ADC interrupt.
Set to enable the ADC interrupt.
0
ECAN
CAN Interrupt Enable bit
Clear to disable the CAN interrupt.
Set to enable the CAN interrupt.
Reset Value = xxxx x000b
bit addressable
135
4126L–CAN–01/08
Table 110. IPL0 Register
IPL0 (S:B8h)
Interrupt Enable Register
7
6
5
4
3
2
1
0
-
PPC
PT2
PS
PT1
PX1
PT0
PX0
Bit
Number
Bit
Mnemonic Description
Reserved
The value read from this bit is indeterminate. Do not set this bit.
7
-
6
PPC
PCA Interrupt Priority bit
Refer to PPCH for priority level
5
PT2
Timer 2 Overflow Interrupt Priority bit
Refer to PT2H for priority level.
4
PS
Serial Port Priority bit
Refer to PSH for priority level.
3
PT1
Timer 1 Overflow Interrupt Priority bit
Refer to PT1H for priority level.
2
PX1
External Interrupt 1 Priority bit
Refer to PX1H for priority level.
1
PT0
Timer 0 Overflow Interrupt Priority bit
Refer to PT0H for priority level.
0
PX0
External Interrupt 0 Priority bit
Refer to PX0H for priority level.
Reset Value = X000 0000b
bit addressable
136
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 111. IPL1 Register
IPL1 (S:F8h)
Interrupt Priority Low Register 1
7
6
5
4
-
-
-
-
Bit
Number
3
2
1
0
POVRL
PADCL
PCANL
Bit
Mnemonic Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
POVRL
Timer Overrun Interrupt Priority Level Less Significant bit
Refer to PI2CH for priority level.
1
PADCL
ADC Interrupt Priority Level Less Significant bit
Refer to PSPIH for priority level.
0
PCANL
CAN Interrupt Priority Level Less Significant bit
Refer to PKBH for priority level.
Reset Value = XXXX X000b
bit addressable
137
4126L–CAN–01/08
Table 112. IPH0 Register
IPH0 (B7h)
Interrupt High Priority Register
7
6
5
4
3
2
1
0
-
PPCH
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
Bit
Number
7
6
5
4
3
2
1
0
Bit
Mnemonic Description
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
PPCH
PCA Interrupt Priority Level Most Significant bit
PPCH PPC Priority level
0
0
Lowest
0
1
1
0
1
1
Highest priority
PT2H
Timer 2 Overflow Interrupt High Priority bit
PT2H PT2 Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
PSH
Serial Port High Priority bit
PSH PS Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
PT1H
Timer 1 Overflow Interrupt High Priority bit
PT1H PT1 Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
PX1H
External Interrupt 1 High Priority bit
PX1H PX1 Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
PT0H
Timer 0 Overflow Interrupt High Priority bit
PT0H PT0 Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
PX0H
External Interrupt 0 High Priority bit
PX0H PX0 Priority Level
0
0
Lowest
0
1
1
0
1
1
Highest
Reset Value = X000 0000b
138
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Table 113. IPH1 Register
IPH1 (S:F7h)
Interrupt high priority Register 1
7
6
5
4
-
-
-
-
Bit
Number
3
2
1
0
POVRH
PADCH
PCANH
Bit
Mnemonic Description
7
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
1
0
POVRH
Timer Overrun Interrupt Priority Level Most Significant bit
POVRH POVRLPriority level
0
0
Lowest
0
1
1
0
1
1
Highest
PADCH
ADC Interrupt Priority Level Most Significant bit
PADCH PADCL Priority level
0
0
Lowest
0
1
1
0
1
1
Highest
PCANH
CAN Interrupt Priority Level Most Significant bit
PCANH PCANLPriority level
0
0
Lowest
0
1
1
0
1
1
Highest
Reset Value = XXXX X000b
139
4126L–CAN–01/08
Electrical Characteristics
Absolute Maximum Ratings
Note:
I = industrial ....................................................... -40°C to 85°C
Stresses at or above those listed under “Absolute
Maximum Ratings” may cause permanent damage to
the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure
to absolute maximum rating conditions may affect
device reliability.
Power Dissipation value is based on the maximum
allowable die temperature and the thermal resistance
of the package.
Storage Temperature ................................... -65°C to + 150°C
Voltage on VCC from VSS .....................................-0.5V to + 6V
Voltage on Any Pin from VSS .....................-0.5V to VCC + 0.2V
Power Dissipation ............................................................. 1 W
DC Parameters for
Standard Voltage
TA = -40°C to +85°C; VSS = 0 V; VCC = 3 volts to 5.5 volts; F = 0 to 40 MHz
Table 114. DC Parameters in Standard Voltage
Symbol
Parameter
Min
VIL
Input Low Voltage
VIH
Input High Voltage except XTAL1, RST
VIH1(2)
VOL
VOH
RRST
Input High Voltage, XTAL1, RST
Typ(1)
Max
Unit
-0.5
0.2Vcc - 0.1
V
0.2 VCC + 0.9
VCC + 0.5
V
0.7 VCC
VCC + 0.5
V
Output Low Voltage, ports 1, 2, 3 and 4(3)
Output High Voltage, ports 1, 2, 3, 4 and 5
RST Pulldown Resistor
V
V
IOL = 1.6 mA
1.0
V
IOL = 3.5 mA
V
VCC - 0.7
V
VCC - 1.5
V
90
IOL = 100 μA
0.3
0.45
VCC - 0.3
50
Test Conditions
200
kΩ
IOH = -10 μA
IOH = -30 μA
IOH = -60 μA
VCC = 5V ± 10%
IIL
Logical 0 Input Current ports 1, 2, 3 and 4
-50
μA
Vin = 0.45V
ILI
Input Leakage Current
±10
μA
0.45V < Vin < VCC
ITL
Logical 1 to 0 Transition Current, ports 1, 2, 3
and 4
-650
μA
Vin = 2.0V
CIO
Capacitance of I/O Buffer
10
pF
Fc = 1 MHz
TA = 25°C
IPD
Power-down Current
400
μA
3V < VCC < 5.5V(4)
160
Power Supply Current
ICC
ICCOP(6) = 0.7 Freq (MHz) + 3 mA
ICCIDLE (5)= 0.6 Freq (MHz) + 2 mA
Notes:
140
1. Typicals are based on a limited number of samples and are not guaranteed. The values listed are at room temperature.
2. Flash retention is guaranteed with the same formula for VCC min down to 0V.
3. Under steady state (non-transient) conditions, IOL must be externally limited as follows:
Maximum IOL per port pin: 10 mA
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Maximum IOL per 8-bit port:
Ports 1, 2 and 3: 15 mA
Maximum total IOL for all output pins: 71 mA
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater
than the listed test conditions.
4. Power-down ICC is measured with all output pins disconnected; XTAL2 NC.; RST = VSS (See Figure 61.).
5. Idle ICC is measured with all output pins disconnected; XTAL1 driven with TCLCH, TCHCL = 5 ns, VIL = VSS + 0.5V, VIH = VCC 0.5V; XTAL2 N.C; RST = VSS (See Figure 60.).
6. Operating ICC is measured with all output pins disconnected; XTAL1 driven with TCLCH, TCHCL = 5 ns (See Figure 62.), VIL =
VSS + 0.5V, VIH = VCC - 0.5V; XTAL2 N.C.; RST = VCC. ICC would be slightly higher if a crystal oscillator used (See Figure
59.).
Figure 59. ICC Test Condition, Active Mode
VCC
ICC
VCC
VaVcc
VCC
RST
(NC)
CLOCK
SIGNAL
XTAL2
XTAL1
VAGND
VSS
All other pins are disconnected.
Figure 60. ICC Test Condition, Idle Mode
VCC
ICC
VCC
VaVcc
RST
(NC)
CLOCK
SIGNAL
XTAL2
XTAL1
VAGND
VSS
All other pins are disconnected.
141
4126L–CAN–01/08
Figure 61. ICC Test Condition, Power-down Mode
VCC
ICC
VCC
VaVcc
RST
(NC)
XTAL2
XTAL1
VAGND
VSS
All other pins are disconnected.
Figure 62. Clock Signal Waveform for ICC Tests in Active and Idle Modes
VCC-0.5V
0.45V
TCLCH
TCHCL
TCLCH = TCHCL = 5ns.
DC Parameters for A/D
Converter
Table 115. DC Parameters for AD Converter in Precision Conversion
Symbol Parameter
AVin
Analog input voltage
VaVcc
Analog supply voltage
Rref(2)
Resistance between Varef and Vss
Varef
Reference voltage
Cai
Analog input Capacitance
Rai
Analog input Resistor
INL
Integral non linearity
DNL
Differential non linearity
OE
Notes:
142
0.7VCC
0.2VCC-0.1
Offset error
Min
Typ(1)
Max
Max Vref
Vss- 0.2
+ 0.6
Vref
Vcc
12
16
2.40
Vcc +
10%
V
V
24
KΩ
3.00
V
60
-2
Unit Test Conditions
pF
During sampling
400
Ω
During sampling
1
2
lsb
0.5
1
lsb
2
lsb
1. Typicals are based on a limited number of samples and are not guaranteed.
2. With ADC enabled.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
AC Parameters
Serial Port Timing - Shift
Register Mode
Table 116. Symbol Description (F = 40 MHz)
Symbol
Parameter
TXLXL
Serial port clock cycle time
TQVHX
Output data set-up to clock rising edge
TXHQX
Output data hold after clock rising edge
TXHDX
Input data hold after clock rising edge
TXHDV
Clock rising edge to input data valid
Table 117. AC Parameters for a Fix Clock (F = 40 MHz)
Symbol
Min
Max
TXLXL
300
ns
TQVHX
200
ns
TXHQX
30
ns
TXHDX
0
ns
TXHDV
Units
117
ns
Table 118. AC Parameters for a Variable Clock
Symbol
Type
Standard
Clock
X2 Clock
x parameter
for -M range
TXLXL
Min
12 T
6T
TQVHX
Min
10 T - x
5T-x
50
ns
TXHQX
Min
2T-x
T-x
20
ns
TXHDX
Min
x
x
0
ns
TXHDV
Max
10 T - x
5 T- x
133
ns
Units
ns
143
4126L–CAN–01/08
Shift Register Timing Waveforms
INSTRUCTION
0
1
2
3
4
5
6
7
8
TXLXL
CLOCK
TXHQX
TQVXH
0
OUTPUT DATA
WRITE to SBUF
1
2
4
5
6
7
TXHDX
TXHDV
INPUT DATA
3
VALID
VALID
SET TI
VALID
VALID
VALID
VALID
VALID
CLEAR RI
External Clock Drive
Characteristics (XTAL1)
VALID
SET RI
Table 119. AC Parameters
Symbol
Parameter
Min
Max
Units
TCLCL
Oscillator Period
25
ns
TCHCX
High Time
5
ns
TCLCX
Low Time
5
ns
TCLCH
Rise Time
5
ns
TCHCL
Fall Time
5
ns
60
%
TCHCX/TCLCX
External Clock Drive
Waveforms
Cyclic ratio in X2 Mode
VCC-0.5V
0.45V
40
0.7VCC
0.2VCC-0.1
TCHCX
TCLCH
TCLCX
TCHCL
TCLCL
AC Testing Input/Output Waveforms
VCC -0.5V
0.2 VCC + 0.9
INPUT/OUTPUT
0.2 VCC - 0.1
0.45 V
AC inputs during testing are driven at VCC - 0.5 for a logic “1” and 0.45V for a logic “0”.
Timing measurement are made at VIH min for a logic “1” and VIL max for a logic “0”.
Float Waveforms
FLOAT
VOH - 0.1V
VOL + 0.1V
144
VLOAD
VLOAD + 0.1V
VLOAD - 0.1V
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
For timing purposes as port pin is no longer floating when a 100 mV change from load
voltage occurs and begins to float when a 100 mV change from the loaded VOH/VOL level
occurs. IOL/IOH ≥ ± 20mA.
Clock Waveforms
Valid in normal clock mode. In X2 Mode XTAL2 must be changed to XTAL2/2.
Flash/EEPROM Memory
Table 120. Memory AC Timing
Vcc = 3.0V to 5.5V, TA = -40°C to +85°C
Symbol
Parameter
Min
TBHBL
Flash/EEPROM Internal Busy
(Programming) Time
NFCY
Number of Flash/EEPROM Erase/Write
Cycles
TFDR
Flash/EEPROM Data Retention Time
Typ
Max
Unit
13
17
ms
100 000
cycles
10
years
Figure 63. Flash Memory - Internal Busy Waveforms
FBUSY bit
A/D Converter
TBHBL
Table 121. AC Parameters for A/D Conversion
Symbol
TSETUP
ADC Clock Frequency
Parameter
Min
Typ
4
Max
Unit
µs
700
KHz
145
4126L–CAN–01/08
Ordering Information
Part Number
Bootloader
Temperature
Range
Package
Packing
Product Marking
T89C51CC02CA-RATIM
T89C51CC02CA-SISIM
T89C51CC02CA-TDSIM
T89C51CC02CA-TISIM
OBSOLETE
T89C51CC02UA-RATIM
T89C51CC02UA-SISIM
T89C51CC02UA-TDSIM
T89C51CC02UA-TISIM
AT89C51CC02CA-RATUM
CAN(2)
Industrial & Green
VQFP32
Tray
89C51CC02CA-UM
AT89C51CC02CA-SISUM
(2)
CAN
Industrial & Green
PLCC28
Stick
89C51CC02CA-UM
AT89C51CC02CA-TDSUM
CAN(2)
Industrial & Green
SOIC24
Stick
89C51CC02CA-UM
(2)
Industrial & Green
SOIC28
Stick
89C51CC02CA-UM
AT89C51CC02CA-TISUM
CAN
AT89C51CC02UA-RATUM
UART(2)
Industrial & Green
VQFP32
Tray
89C51CC02UA-UM
AT89C51CC02UA-SISUM
UART
(2)
Industrial & Green
PLCC28
Stick
89C51CC02UA-UM
AT89C51CC02UA-TDSUM
UART(2)
Industrial & Green
SOIC24
Stick
89C51CC02UA-UM
(2)
Industrial & Green
SOIC28
Stick
89C51CC02UA-UM
AT89C51CC02UA-TISUM
UART
Factory default programming for T89C51CC02CA-xxxx is Bootloader CAN and
HSB = BBh:
•
X1 mode
•
BLJB = 0 : jump to Bootloader
•
LB2 = 0 : Security Level 3.(1)
Factory default programming for T89C51CC02UA-xxxx is Bootloader UART and
HSB = BBh:
•
X1 mode
•
BLJB = 0 : jump to Bootloader
•
LB2 = 0 : Security Level 3.(1)
Notes:
146
1. LB2 = 0 is not described in Table 22 Program load bit. LB2 = 0 is equivalent to LB1 =
0: Security Level 3.
2. Customer can change these modes by re-programming with a parallel programmer,
this can be done by an Atmel distributor.
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
Package Drawings
VQFP32
147
4126L–CAN–01/08
STANDARD NOTES FOR PQFP/ VQFP / TQFP / DQFP
1/ CONTROLLING DIMENSIONS : INCHES
2/ ALL DIMENSIONING AND TOLERANCING CONFORM TO ANSI Y 14.5M 1982.
3/ "D1 AND E1" DIMENSIONS DO NOT INCLUDE MOLD PROTUSIONS.
MOLD PROTUSIONS SHALL NOT EXCEED 0.25 mm (0.010 INCH).
THE TOP PACKAGE BODY SIZE MAY BE SMALLER THAN THE BOTTOM
PACKAGE BODY SIZE BY AS MUCH AS 0.15 mm.
4/ DATUM PLANE "H" LOCATED AT MOLD PARTING LINE AND
COINCIDENT WITH LEAD, WHERE LEAD EXITS PLASTIC BODY AT
BOTTOM OF PARTING LINE.
5/ DATUM "A" AND "D" TO BE DETERMINED AT DATUM PLANE H.
6/ DIMENSION " f " DOES NOT INCLUDE DAMBAR PROTUSION ALLOWABLE
DAMBAR PROTUSION SHALL BE 0.08mm/.003" TOTAL IN EXCESS OF THE
" f " DIMENSION AT MAXIMUM MATERIAL CONDITION .
DAMBAR CANNOT BE LOCATED ON THE LOWER RADIUS OR THE FOOT.
148
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
PLCC28
149
4126L–CAN–01/08
STANDARD NOTES FOR PLCC
1/ CONTROLLING DIMENSIONS : INCHES
2/ DIMENSIONING AND TOLERANCING PER ANSI Y 14.5M - 1982.
3/ "D" AND "E1" DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTUSIONS.
MOLD FLASH OR PROTUSIONS SHALL NOT EXCEED 0.20 mm (.008 INCH) PER
SIDE.
150
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
SOIC24
151
4126L–CAN–01/08
SOIC28
152
AT/T89C51CC02
4126L–CAN–01/08
AT/T89C51CC02
153
4126L–CAN–01/08
Datasheet Revision
History
Changes from 4126C10/02 to 4126D - 04/03
1. Changed the endurance of Flash to 100, 000 Write/Erase cycles.
2. Added note on Flash retention formula for VIH1, in Section "DC Parameters for
Standard Voltage", page 141.Changes from 4129F-11/02 to 4129G-04/03
1. Changed the endurance of Flash to 100, 000 Write/Erase cycles.
2. Added note on Flash retention formula for VIH1, in Section "DC Parameters for
Standard Voltage", page 141.
Changes from 4126D 05/03 to 4126E - 10/03
1. Updated “Electrical Characteristics” on page 140.
Changes from 4126E 10/03 to 4126F - 12/03
1. Changed value of IPDMAX to 400, Section "Absolute Maximum Ratings",
page 140.
2. Corrected Figure 39 on page 82.
2. PCA , CPS0, register correction, Section "PCA Registers", page 121.
3. Cross Memory section added. Section "Operation Cross Memory Access",
page 44.
Changes from 4126F 12/03 4126G - 08/04
1. Figure clock-out mode modified see, Figure 30 on page 65.
2. Corrected error in Table 51 on page 70, (1.25ms to 1.25s) for Time-out
Computation.
3. Added explanation on the CAN protocol, see Section “CAN Controller”, page 73.
Changes from 4126G 08/04 to 4126H - 01/05
1. Various minor corrections throughout the document.
Changes from 4126H 01/05 to 4126I 11/05
1. Added Green product ordering information.
Changes from 4126I to
4126J 05/06
1. Minor corrections throughout the document.
Changes from 4126J to
4126K 11/07
1. Updated Package drawings.
Changes from 4126K
11/07 to 4126L 02/08
1. Removed non-green part numbers from ordering information.
154
AT/T89C51CC02
4126L–CAN–01/08
Table of Contents
Table of
Contents
Features ................................................................................................. 1
Description ............................................................................................ 2
Block Diagram ....................................................................................... 2
Pin Configurations ................................................................................ 3
Pin Description...................................................................................... 5
I/O Configurations ................................................................................................. 7
Port Structure ....................................................................................................... 7
Read-Modify-Write Instructions ............................................................................ 8
Quasi Bi-directional Port Operation ...................................................................... 8
SFR Mapping ....................................................................................... 10
Clock .................................................................................................... 16
Description ......................................................................................................... 16
Register .............................................................................................................. 19
Power Management ............................................................................ 20
Reset Pin .............................................................................................. 20
At Power-up (cold reset)..................................................................................... 20
During a Normal Operation (Warm Reset) ......................................................... 21
Watchdog Reset ................................................................................................. 21
Reset Recommendation to Prevent Flash Corruption ......................................... 22
Idle Mode............................................................................................................ 22
Power-down Mode ............................................................................................. 22
Registers ............................................................................................................. 25
Data Memory ....................................................................................... 26
Internal Space .................................................................................................... 26
Dual Data Pointer ............................................................................................... 28
Registers ............................................................................................................ 29
EEPROM Data Memory ....................................................................... 31
Write Data in the Column Latches......................................................................
Programming ......................................................................................................
Read Data ..........................................................................................................
Examples............................................................................................................
Registers ............................................................................................................
31
31
31
32
33
i
Program/Code Memory ...................................................................... 34
Flash Memory Architecture ................................................................................ 34
Overview of FM0 Operations.............................................................................. 36
Registers ............................................................................................................ 42
Operation Cross Memory Access ..................................................... 44
Sharing Instructions ........................................................................... 45
In-System Programming (ISP) ........................................................... 47
Flash Programming and Erasure .......................................................................
Boot Process ......................................................................................................
Application-Programming-Interface ....................................................................
XROW Bytes ......................................................................................................
Hardware Conditions ..........................................................................................
Hardware Security Byte......................................................................................
47
48
48
49
49
50
Serial I/O Port ...................................................................................... 51
Framing Error Detection .................................................................................... 51
Automatic Address Recognition ......................................................................... 52
Given Address .................................................................................................... 52
Broadcast Address ............................................................................................. 53
Registers ............................................................................................................. 54
Timers/Counters ................................................................................. 57
Timer/Counter Operations ..................................................................................
Timer 0 ...............................................................................................................
Timer 1 ...............................................................................................................
Interrupt ..............................................................................................................
Registers ............................................................................................................
57
57
59
60
61
Timer 2 ................................................................................................. 64
Auto-Reload Mode ............................................................................................. 64
Programmable Clock-Output .............................................................................. 65
Registers ............................................................................................................ 66
Watchdog Timer .................................................................................. 69
Watchdog Programming...................................................................................... 70
Watchdog Timer During Power-down Mode and Idle ...................... 71
Register .............................................................................................................. 71
CAN Controller .................................................................................... 73
ii
Table of Contents
CAN Protocol...................................................................................................... 73
CAN Controller Description ................................................................................ 77
CAN Controller Mailbox and Registers Organization ......................................... 78
CAN Controller Management ............................................................. 80
IT CAN Management..........................................................................................
Bit Timing and Baud Rate ..................................................................................
Fault Confinement ..............................................................................................
Acceptance Filter................................................................................................
Data and Remote Frame ....................................................................................
Time Trigger Communication (TTC) and Message Stamping ............................
CAN Autobaud and Listening Mode ...................................................................
Routine Examples ..............................................................................................
CAN SFRs ..........................................................................................................
Registers ............................................................................................................
81
84
86
87
88
89
90
90
93
94
Programmable Counter Array (PCA) ............................................... 114
PCA Timer ........................................................................................................
PCA Modules ...................................................................................................
PCA Interrupt....................................................................................................
PCA Capture Mode ..........................................................................................
16-bit Software Timer Mode .............................................................................
High Speed Output Mode .................................................................................
Pulse Width Modulator Mode ...........................................................................
PCA Registers ..................................................................................................
114
116
117
117
118
119
119
121
Analog-to-Digital Converter (ADC) .................................................. 126
Features ........................................................................................................... 126
ADC Port1 I/O Functions .................................................................................. 126
VAREF ............................................................................................................. 126
ADC Converter Operation ................................................................................ 127
Voltage Conversion .......................................................................................... 128
Clock Selection................................................................................................. 128
ADC Standby Mode.......................................................................................... 128
IT ADC Management......................................................................................... 129
Routine Examples ............................................................................................ 129
Registers ........................................................................................................... 130
Interrupt System ............................................................................... 132
Introduction....................................................................................................... 132
Registers .......................................................................................................... 134
Electrical Characteristics ................................................................. 140
iii
Absolute Maximum Ratings..............................................................................
DC Parameters for Standard Voltage...............................................................
DC Parameters for A/D Converter....................................................................
AC Parameters .................................................................................................
140
140
142
143
Ordering Information ........................................................................ 146
Package Drawings ............................................................................ 147
VQFP32............................................................................................................
PLCC28 ............................................................................................................
.........................................................................................................................
SOIC24.............................................................................................................
SOIC28.............................................................................................................
147
149
150
151
152
Datasheet Revision History ............................................................. 154
Changes from 4126C-10/02 to 4126D - 04/03 .................................................
Changes from 4126D -05/03 to 4126E - 10/03 ................................................
Changes from 4126E - 10/03 to 4126F - 12/03 ................................................
Changes from 4126F - 12/03 4126G - 08/04 ...................................................
Changes from 4126G - 08/04 to 4126H - 01/05 ...............................................
Changes from 4126H - 01/05 to 4126I 11/05 ...................................................
Changes from 4126I to 4126J 05/06 ................................................................
Changes from 4126J to 4126K 11/07...............................................................
Changes from 4126K 11/07 to 4126L 02/08 ....................................................
154
154
154
154
154
154
154
154
154
Table of Contents ................................................................................... i
iv
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4126L–CAN–01/08