Holtek HT46RU232 A/d type 8-bit otp mcu with uart Datasheet

HT46RU232
A/D Type 8-Bit OTP MCU with UART
Technical Document
· Tools Information
· FAQs
· Application Note
- HA0005E Controlling the I^2C bus with the HT48 & HT46 MCU Series
- HA0013E HT48 & HT46 LCM Interface Design
- HA0017E Controlling the Read/Write Function of the HT24 Series EEPROM Using the HT49 Series MCUs
- HA0075E MCU Reset and Oscillator Circuits Application Note
Features
· Operating voltage:
· 8-level subroutine nesting
fSYS=4MHz: 2.2V~5.5V
fSYS=8MHz: 3.3V~5.5V
· 8 channels 12-bit resolution A/D converter
· 4-channel 8-bit PWM output shared with
· 40 bidirectional I/O lines (max.)
four I/O lines
· 1 interrupt input shared with an I/O line
· Bit manipulation instruction
· One 8-bit and Two 16-bit programmable timer/event
· 16-bit table read instruction
counter with overflow interrupt
· 63 powerful instructions
· On-chip crystal and RC oscillator
· All instructions in one or two machine cycles
· Watchdog Timer
· Low voltage reset function
· 4096´16 program memory
· I2C Bus (slave mode)
· 192´8 data memory RAM
· UART (Universal Asynchronous Receiver/
· Supports PFD for sound generation
Transmitter)
· HALT function and wake-up feature reduce power
· 28-pin SKDIP/SOP, 48-pin SSOP packages
consumption
· Up to 0.5ms instruction cycle with 8MHz system clock
at VDD=5V
General Description
Width Modulation function, I2C interface, UART bus,
HALT and wake-up functions, enhance the versatility of
these devices to suit a wide range of A/D application
possibilities such as sensor signal processing, motor
driving, industrial control, consumer products, subsystem controllers, etc.
The HT46RU232 is 8-bit, high performance, RISC architecture microcontroller devices specifically designed
for A/D applications that interface directly to analog signals, such as those from sensors.
The advantages of low power consumption, I/O flexibility, programmable frequency divider, timer functions,
oscillator options, multi-channel A/D Converter, Pulse
I2C is a trademark of Philips Semiconductors.
Rev. 1.00
1
April 23, 2008
HT46RU232
Block Diagram
M
T M R 2 C
T M R 2
M
T M R 1 C
T M R 1
P F D 1
In te rru p t
C ir c u it
U
P r e s c a le r
X
fS
Y S
fS
Y S
T M R 2
T M R 1
U
X
fS
Y S
/4
S T A C K
P ro g ra m
E P R O M
P ro g ra m
C o u n te r
IN T C
M
T M R 0 C
T M R 0
P F D 0
U
P r e s c a le r
X
T M R 0
B P
In s tr u c tio n
R e g is te r
M
M P
M
U
W D T
X
D a ta
M e m o ry
P F C
P o rt F
P F
P A 5
M U X
In s tr u c tio n
D e c o d e r
A L U
O S
R E
V D
V S
S
S
D
C 1
A C C
H A L T
P o rt C
P C
E N /D IS
/4
P F 0 ~ P F 7
P D 0 /P W M 0 ~ P D 3 /P W M 3
P D 4 ~ P D 7
P C 0 /T X
P C 1 /R X
P C 2 ~ P C 7
8 -C h a n n e l
A /D C o n v e rte r
L V R
P B C
P o rt B
P B
P A C
P A
I2 C B u s
S la v e M o d e
Rev. 1.00
Y S
W D T O S C
U A R T
P C C
O S C 2
P o rt D
P D
S h ifte r
T im in g
G e n e ra to r
fS
X
P W M
P D C
S T A T U S
U
2
P o rt A
P B 0 /A N 0 ~
P B 7 /A N 7
P A
P A
P A
P A
P A
P A
0 ~ P
3 /P
4
5 /IN
6 /S
7 /S
A 2
F D
T
D A
C L
April 23, 2008
HT46RU232
Pin Assignment
P B 5 /A N 5
1
4 8
P B 6 /A N 6
P B 4 /A N 4
2
4 7
P B 7 /A N 7
P A 3 /P F D
3
4 6
P A 4
P A 2
4
4 5
P A 5 /IN T
P A 1
5
4 4
P A 6 /S D A
P A 0
6
4 3
P A 7 /S C L
P B 3 /A N 3
7
4 2
P F 4
P B 2 /A N 2
8
4 1
P F 5
P B 1 /A N 1
9
4 0
P F 6
P B 0 /A N 0
1 0
3 9
P F 7
P B 5 /A N 5
1
2 8
P B 6 /A N 6
T M R 2
1 1
3 8
O S C 2
P B 4 /A N 4
2
2 7
P B 7 /A N 7
P F 3
1 2
3 7
O S C 1
P A 3 /P F D
3
2 6
P A 4
P F 2
1 3
3 6
V D D
P A 2
4
2 5
P A 5 /IN T
P F 1
1 4
3 5
R E S
P A 1
5
2 4
P A 6 /S D A
P D 7
1 5
3 4
T M R 1
P A 0
6
2 3
P A 7 /S C L
P D 6
1 6
3 3
P D 3 /P W M 3
P B 3 /A N 3
7
2 2
O S C 2
P D 5
1 7
3 2
P D 2 /P W M 2
P B 2 /A N 2
8
2 1
O S C 1
P D 4
1 8
3 1
P D 1 /P W M 1
P B 1 /A N 1
9
2 0
V D D
V S S
1 9
3 0
P D 0 /P W M 0
P B 0 /A N 0
1 0
1 9
R E S
P F 0
2 0
2 9
P C 7
V S S
1 1
1 8
P D 1 /P W M 1 /T M R 1
T M R 0
2 1
2 8
P C 6
P C 0 /T X
1 2
1 7
P D 0 /P W M 0
P C 0 /T X
2 2
2 7
P C 5
P C 1 /R X
1 3
1 6
P C 4
P C 1 /R X
2 3
2 6
P C 4
P C 2
1 4
1 5
P C 3
P C 2
2 4
2 5
P C 3
H T 4 6 R U 2 3 2
2 8 S K D IP -A /S O P -A
H T 4 6 R U 2 3 2
4 8 S S O P -A
Pin Description
Pin Name
PA0~PA2
PA3/PFD
PA4
PA5/INT
PA6/SDA
PA7/SCL
PB0/AN0
PB1/AN1
PB2/AN2
PB3/AN3
PB4/AN4
PB5/AN5
PB6/AN6
PB7/AN7
PC0/TX
PC1/RX
PC2~PC7
PD0/PWM0
PD1/PWM1
PD2/PWM2
PD3/PWM3
PD4~PD7
Rev. 1.00
I/O
Options
Description
I/O
Pull-high
Wake-up
PA3 or PFD
I/O or Serial Bus
Bidirectional 8-bit input/output port. Each bit can be configured as wake-up
input by option (bit option). Software instructions determine the CMOS output or Schmitt trigger input with or without pull-high resistor (determined by
pull-high options: bit option). The PFD and INT are pin-shared with PA3
and PA5, respectively. Once the I2C Bus function is used, the internal registers related to PA6 and PA7 cannot be used.
Pull-high
Bidirectional 8-bits input/output port. Software instructions determine the
CMOS output, Schmitt trigger input with or without pull-high resistor (determined by pull-high option: bit option) or A/D input. Once a PB line is selected as an A/D input (by using software control), the I/O function and
pull-high resistor are automatically disabled.
Pull-high
Bidirectional 8-bit input/output port. Software instructions determine the
CMOS output, Schmitt trigger input with or without pull-high resistor (determine by pull-high option: bit option).
TX and RX are pin-shared with PC0 and PC1, once the UART Bus function
is used, the internal registers related to PC0 and PC1 cannot be used. Software instructions determine the UART function to be used.
Pull-high
PWM
Bidirectional 8-bit input/output port. Software instructions determine the
CMOS output, Schmitt trigger input with or without a pull-high resistor (determined by pull-high option: bit option). The PWM0/PWM1/PWM2/ PWM3
output function are pin-shared with PD0/PD1/PD2/PD3 (depending on the
PWM options).
I/O
I/O
I/O
3
April 23, 2008
HT46RU232
Pin Name
I/O
Options
Description
I/O
Pull-high
Bidirectional 8-bit input/output port. Software instructions determine the
CMOS output, Schmitt trigger input with or without pull-high resistor (determine by pull-high option: bit option).
TMR0
I
¾
Timer/Event Counter 0 Schmitt trigger input (without pull-high resistor)
TMR1
I
¾
Timer/Event Counter 1 Schmitt trigger input (without pull-high resistor).
TMR2
I
¾
Timer/Event Counter 2 Schmitt trigger input (without pull-high resistor).
RES
I
¾
Schmitt trigger reset input, active low
VSS
¾
¾
Negative power supply, ground
VDD
¾
¾
Positive power supply
OSC1
OSC2
I
O
Crystal or RC
PF0~PF7
OSC1 and OSC2 are connected to an RC network or a crystal (by options)
for the internal system clock. In the case of RC operation, OSC2 is the
output terminal for 1/4 system clock.
Absolute Maximum Ratings
Supply Voltage ...........................VSS-0.3V to VSS+6.0V
Storage Temperature ............................-50°C to 125°C
Input Voltage..............................VSS-0.3V to VDD+0.3V
IOL Total ..............................................................150mA
Total Power Dissipation .....................................500mW
Operating Temperature...........................-40°C to 85°C
IOH Total............................................................-100mA
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may
cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed
in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.
D.C. Characteristics
Ta=25°C
Test Conditions
Symbol
Parameter
Min.
Typ.
Max.
Unit
fSYS=4MHz
2.2
¾
5.5
V
fSYS=8MHz
3.3
¾
5.5
V
Conditions
VDD
VDD
Operating Voltage
¾
Operating Current
(Crystal OSC)
3V No load, f
SYS=4MHz
5V ADC Off, UART Off
¾
0.6
1.5
mA
¾
2
4
mA
Operating Current
(RC OSC)
3V No load, f
SYS=4MHz
5V ADC Off, UART Off
¾
0.8
1.5
mA
¾
2.5
4
mA
Operating Current
(Crystal OSC, RC OSC)
3V No load, f
SYS=4MHz,
5V ADC Off, UART On
¾
1
2
mA
¾
3
6
mA
IDD4
Operating Current
(Crystal OSC, RC OSC)
5V
No load, fSYS=8MHz,
ADC Off, UART Off
¾
4
8
mA
IDD5
Operating Current
(Crystal OSC, RC OSC)
5V
No load, fSYS=8MHz,
ADC Off, UART On
¾
5
10
mA
ISTB2
Standby Current
(WDT Disabled)
3V
¾
¾
1
mA
¾
¾
2
mA
VIL1
Input Low Voltage for I/O Ports,
TMR0, TMR1 and INT
¾
¾
0
¾
0.3VDD
V
VIH1
Input High Voltage for I/O Ports,
TMR0, TMR1 and INT
¾
¾
0.7VDD
¾
VDD
V
IDD1
IDD2
IDD3
Rev. 1.00
No load, system HALT
5V
4
April 23, 2008
HT46RU232
Test Conditions
Symbol
Parameter
VDD
Conditions
Min.
Typ.
Max.
Unit
VIL2
Input Low Voltage (RES)
¾
¾
0
¾
0.4VDD
V
VIH2
Input High Voltage (RES)
¾
¾
0.9VDD
¾
VDD
V
VLVR1
Low Voltage Reset 1
¾
Configuration option: 2.1V
1.98
2.1
2.22
V
VLVR2
Low Voltage Reset 2
¾
Configuration option: 3.15V
2.98
3.15
3.32
V
VLVR3
Low Voltage Reset 3
¾
Configuration option: 4.2V
3.98
4.2
4.42
V
VLVR
Low Voltage Reset Voltage
¾
2.7
3
3.3
V
IOL
4
8
¾
mA
I/O Port Sink Current
10
20
¾
mA
-2
-4
¾
mA
-5
-10
¾
mA
20
60
100
kW
10
30
50
kW
¾
0.5
1
mA
¾
1.5
3
mA
3V
¾
VOL=0.1VDD
5V
IOH
3V
I/O Port Source Current
VOH=0.9VDD
5V
RPH
3V
¾
Pull-high Resistance
5V
Additional Power Consumption
if A/D Converter is Used
3V
DNL
ADC Differential Non-Linear
5V tAD=1ms
¾
¾
±2
LSB
INL
ADC Integral Non-Linear
5V tAD=1ms
¾
±2.5
±4
LSB
¾
¾
12
Bits
IADC
RESOLU Resolution
5V
tAD=1ms
¾
¾
A.C. Characteristics
Ta=25°C
Test Conditions
Symbol
Parameter
fSYS
fTIMER
tWDTOSC
System Clock
Timer I/P Frequency
(TMR0/TMR1/TMR2)
Min.
Typ.
Max.
Unit
Conditions
VDD
¾
2.2V~5.5V
400
¾
4000
kHz
¾
3.3V~5.5V
400
¾
8000
kHz
¾
2.2V~5.5V
0
¾
4000
kHz
¾
3.3V~5.5V
0
¾
8000
kHz
3V
¾
45
90
180
ms
5V
¾
32
65
130
ms
¾
1
¾
¾
ms
¾
1024
¾
*tSYS
Watchdog Oscillator Period
tRES
External Reset Low Pulse Width
¾
tSST
System Start-up Timer Period
¾
tINT
Interrupt Pulse Width
¾
¾
1
¾
¾
ms
tAD
A/D Clock Period
¾
¾
1
¾
¾
ms
tADC
A/D Conversion Time
¾
¾
¾
80
¾
tAD
tADCS
A/D Sampling Time
¾
¾
¾
32
¾
tAD
tIIC
I2C Bus Clock Period
¾
64
¾
¾
*tSYS
Wake-up from HALT
Connect to external
pull-high resistor 2kW
Note: *tSYS=1/fSYS
Rev. 1.00
5
April 23, 2008
HT46RU232
Functional Description
the value of the PC is incremented by 1. The PC then
points to the memory word containing the next instruction code. When executing a jump instruction, conditional skip execution, loading a PCL register, a
subroutine call, an initial reset, an internal interrupt, an
external interrupt, or returning from a subroutine, the PC
manipulates the program transfer by loading the address corresponding to each instruction.
Execution Flow
The system clock is derived from either a crystal or an
RC oscillator. It is internally divided into four
non-overlapping clocks. One instruction cycle consists
of four system clock cycles. Instruction fetching and execution are pipelined in such a way that a fetch takes
one instruction cycle while decoding and execution
takes the next instruction cycle. The pipelining scheme
makes it possible for each instruction to be effectively
executed in a cycle. If an instruction changes the value
of the program counter, two cycles are required to complete the instruction.
The conditional skip is activated by instructions. Once
the condition is met, the next instruction, fetched during
the current instruction execution, is discarded and a
dummy cycle replaces it to get a proper instruction; otherwise proceed to the next instruction.
Program Counter - PC
The lower byte of the PC (PCL) is a readable and
writeable register (06H). Moving data into the PCL performs a short jump. The destination is within 256 locations.
The program counter (PC) is 12 bits wide and it controls
the sequence in which the instructions stored in the program ROM are executed. The contents of the PC can
specify a maximum of 4096 addresses. After accessing
a program memory word to fetch an instruction code,
S y s te m
C lo c k
T 1
T 2
T 3
T 4
When a control transfer takes place, an additional
dummy cycle is required.
T 1
T 2
T 3
T 4
T 1
T 2
T 3
T 4
O S C 2 ( R C o n ly )
P C
P C
P C + 1
F e tc h IN S T (P C )
E x e c u te IN S T (P C -1 )
P C + 2
F e tc h IN S T (P C + 1 )
E x e c u te IN S T (P C )
F e tc h IN S T (P C + 2 )
E x e c u te IN S T (P C + 1 )
Execution Flow
Mode
Program Counter
*11
*10
*9
*8
*7
*6
*5
*4
*3
*2
*1
*0
Initial Reset
0
0
0
0
0
0
0
0
0
0
0
0
External Interrupt or
A/D Converter Interrupt
0
0
0
0
0
0
0
0
0
1
0
0
Timer/Event Counter 0 Overflow
0
0
0
0
0
0
0
0
1
0
0
0
Timer/Event Counter 1 Overflow
0
0
0
0
0
0
0
0
1
1
0
0
UART Interrupt
0
0
0
0
0
0
0
1
0
0
0
0
I2C Bus Interrupt
0
0
0
0
0
0
0
1
0
1
0
0
Timer/Event Counter 2 Overflow
0
0
0
0
0
0
0
1
1
0
0
0
Loading PCL
*11
*10
*9
*8
@7
@6
@5
@4
@3
@2
@1
@0
Jump, Call Branch
#11
#10
#9
#8
#7
#6
#5
#4
#3
#2
#1
#0
Return from Subroutine
S11
S10
S9
S8
S7
S6
S5
S4
S3
S2
S1
S0
Skip
Program Counter + 2
Program Counter
Note:
*11~*0: Program counter bits
#11~#0: Instruction code bits
Rev. 1.00
S11~S0: Stack register bits
@7~@0: PCL bits
6
April 23, 2008
HT46RU232
· Location 018H
Program Memory - EPROM
This area is reserved for the Timer/Event Counter 2 interrupt service program. If a timer interrupt results
from a Timer/Event Counter 2 overflow, and if the interrupt is enabled and the stack is not full, the program
begins execution at location 018H.
The program memory (EPROM) is used to store the program instructions which are to be executed. It also contains data, table, and interrupt entries, and is organized
into 4096´16 bits which are addressed by the program
counter and table pointer.
· Table location
Certain locations in the ROM are reserved for special
usage:
Any location in the ROM can be used as a look-up table. The instructions ²TABRDC [m]² (the current page,
page=256 words) and ²TABRDL [m]² (the last page)
transfer the contents of the lower-order byte to the
specified data memory, and the contents of the
higher-order byte to TBLH (Table Higher-order byte
register) (08H). Only the destination of the lower-order
byte in the table is well-defined; the other bits of the table word are all transferred to the lower portion of
TBLH. The TBLH is read only, and the table pointer
(TBLP) is a read/write register (07H), indicating the table location. Before accessing the table, the location
should be placed in TBLP. All the table related instructions require 2 cycles to complete the operation.
These areas may function as a normal ROM depending upon the users requirements.
· Location 000H
Location 000H is reserved for program initialization.
After chip reset, the program always begins execution
at this location.
· Location 004H
Location 004H is reserved for the external interrupt
service program or A/D conversion interrupt (determined by option). If the INT input pin or A/D conversion interrupt is activated, and the interrupt is enabled,
and the stack is not full, the program begins execution
at location 004H.
· Location 008H
Location 008H is reserved for the Timer/Event Counter 0 interrupt service program. If a timer interrupt results from a Timer/Event Counter 0 overflow, and if the
interrupt is enabled and the stack is not full, the program begins execution at location 008H.
0 0 0 H
D e v ic e In itia liz a tio n P r o g r a m
0 0 4 H
0 0 8 H
· Location 00CH
0 0 C H
This area is reserved for the Timer/Event Counter 1 interrupt service program. If a timer interrupt results
from a Timer/Event Counter 1 overflow, and if the interrupt is enabled and the stack is not full, the program
begins execution at location 00CH.
E x te r n a l In te r r u p t S u b r o u tin e ,
A /D C o n v e r s io n In te r r u p t
T im e r /E v e n t C o u n te r 0 In te r r u p t S u b r o u tin e
T im e r /E v e n t C o u n te r 1 In te r r u p t S u b r o u tin e
0 1 0 H
U A R T B u s In te rru p t
0 1 4 H
0 1 8 H
I2C
B u s In te rru p t
P ro g ra m
M e m o ry
T im e r /E v e n t C o u n te r 2 In te r r u p t S u b r o u tin e
· Location 010H
This area is reserved for the UART interrupt service
program. If the UART interrupt resulting from transmission/reception is completed, and if the interrupt is
enable and the stack is not full, the program begins
execution at location 010H.
n 0 0 H
L o o k - u p ta b le ( 2 5 6 w o r d s )
n F F H
F 0 0 H
· Location 014H
L o o k - u p ta b le ( 2 5 6 w o r d s )
F F F H
2
1 6 b its
This area is reserved for the I C Bus interrupt service
program. If the I2C Bus interrupt resulting from a slave
address is match or completed one byte of data transfer, and if the interrupt is enable and the stack is not
full, the program begins execution at location 014H.
N o te : n ra n g e s fro m
0 to F
Program Memory
Table Location
Instruction
*11
*10
*9
*8
*7
*6
*5
*4
*3
*2
*1
*0
TABRDC [m]
P11
P10
P9
P8
@7
@6
@5
@4
@3
@2
@1
@0
TABRDL [m]
1
1
1
1
@7
@6
@5
@4
@3
@2
@1
@0
Table Location
Note: *11~*0: Table location bits
@7~@0: Table pointer bits
Rev. 1.00
P11~P8: Current program counter bits
7
April 23, 2008
HT46RU232
Stack Register - STACK
access the RAM by combining corresponding indirect
addressing registers.
This is a special part of the memory which is used to
save the contents of the program counter only. The
stack is organized into 8 levels and is neither part of the
data nor part of the program space, and is neither readable nor writeable. The activated level is indexed by the
stack pointer (SP) and is neither readable nor writeable.
At the state of a subroutine call or an interrupt acknowledgment, the contents of the program counter are
pushed onto the stack. At the end of the subroutine or an
interrupt routine, signaled by a return instruction (RET or
RETI), the program counter is restored to its previous
value from the stack. After a chip reset, the SP will point
to the top of the stack.
0 0 H
M P 0
0 2 H
In d ir e c t A d d r e s s in g R e g is te r 1
0 3 H
M P 1
0 4 H
0 5 H
A C C
0 6 H
P C L
0 7 H
T B L P
0 8 H
T B L H
0 9 H
0 A H
If the stack is full and a non-masked interrupt takes
place, the interrupt request flag will be recorded but the
acknowledgment will be inhibited. When the stack
pointer is decremented (by RET or RETI), the interrupt is
serviced. This feature prevents stack overflow, allowing
the programmer to use the structure more easily. If the
stack is full and a ²CALL² is subsequently executed,
stack overflow occurs and the first entry will be lost (only
the most recent 8 return addresses are stored).
Data Memory - RAM
The data memory (RAM) is designed with 238´8 bits,
and is divided into two functional groups, namely; special function registers (46´8 bits) and general purpose
data memory (192´8 bits) most of which are readable/writeable, although some are read only.
S T A T U S
0 B H
IN T C 0
0 C H
T M R 0 H
0 D H
T M R 0 L
0 E H
T M R 0 C
0 F H
T M R 1 H
1 0 H
T M R 1 L
1 1 H
T M R 1 C
1 2 H
P A
1 3 H
P A C
1 4 H
P B
1 5 H
P B C
1 6 H
P C
1 7 H
P C C
1 8 H
P D
1 9 H
P D C
1 A H
P W M 0
1 B H
P W M 1
1 C H
P W M 2
1 D H
P W M 3
1 E H
IN T C 1
S p e c ia l P u r p o s e
D a ta M e m o ry
1 F H
The unused space before 40H is reserved for future expanded usage and reading these locations will get
²00H². The space before 40H is overlapping in each
bank. The general purpose data memory, addressed
from 40H to FFH, is used for data and control information under instruction commands.
All of the data memory areas can handle arithmetic,
logic, increment, decrement and rotate operations directly. Except for some dedicated bits, each bit in the
data memory can be set and reset by ²SET [m].i² and
²CLR [m].i². They are also indirectly accessible through
memory pointer registers (MP0;01H/MP1;03H). The
space before 40H is overlapping in each bank.
2 0 H
H A D R
2 1 H
H C R
2 2 H
H S R
2 3 H
H D R
2 4 H
A D R L
2 5 H
A D R H
2 6 H
A D C R
2 7 H
A C S R
2 8 H
P F
2 9 H
P F C
2 A H
2 B H
2 C H
2 D H
T M R 2
2 E H
T M R 2 C
2 F H
Indirect Addressing Register
Location 00H and 02H are indirect addressing registers
that are not physically implemented. Any read/write operation of [00H] and [02H] accesses the RAM pointed to
by MP0 (01H) and MP1(03H) respectively. Reading location 00H or 02H indirectly returns the result 00H.
While, writing it indirectly leads to no operation. The
function of data movement between two indirect addressing registers is not supported. The memory pointer
registers, MP0 and MP1, are both 8-bit registers used to
Rev. 1.00
In d ir e c t A d d r e s s in g R e g is te r 0
0 1 H
3 0 H
U S R
3 1 H
U C R 1
3 2 H
U C R 2
3 3 H
T X R /R X R
3 4 H
3 5 H
B R G
3 F H
4 0 H
F F H
G e n e ra l P u rp o s e
D a ta M e m o ry
(1 9 2 B y te s )
: U n u s e d
R e a d a s "0 0 "
RAM Mapping
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April 23, 2008
HT46RU232
Accumulator - ACC
cuting the subroutine call, the status register will not be
automatically pushed onto the stack. If the contents of
the status is important, and if the subroutine is likely to
corrupt the status register, the programmer should take
precautions and save it properly.
The accumulator is closely related to ALU operations. It
is also mapped to location 05H of the RAM and capable
of operating with immediate data. The data movement
between two data memory locations must pass through
the accumulator.
Interrupts
Arithmetic and Logic Unit - ALU
The device provides an external interrupt or A/D conversion interrupt (by option), three internal timer/event
counter interrupt, UART interrupt and the I2C Bus interrupts. The interrupt control register 0 (INTC0;0BH) and
interrupt control register 1 (INTC1;1EH) contains the interrupt control bits to set the enable/disable and the interrupt request flags.
This circuit performs 8-bit arithmetic and logic operations.
The ALU provides the following functions:
· Arithmetic operations (ADD, ADC, SUB, SBC, DAA)
· Logic operations (AND, OR, XOR, CPL)
· Rotation (RL, RR, RLC, RRC)
· Increment and Decrement (INC, DEC)
Once an interrupt subroutine is serviced, all the other interrupts will be blocked (by clearing the EMI bit). This
scheme may prevent any further interrupt nesting. Other
interrupt requests may occur during this interval but only
the interrupt request flag is recorded. If a certain interrupt requires servicing within the service routine, the
EMI bit and the corresponding bit of INTC0 and INTC1
may be set to allow interrupt nesting. If the stack is full,
the interrupt request will not be acknowledged, even if the
related interrupt is enabled, until the stack pointer is decremented. If immediate service is desired, the stack must
be prevented from becoming full.
· Branch decision (SZ, SNZ, SIZ, SDZ ....)
The ALU not only saves the results of a data operation
but also changes the status register.
Status Register - STATUS
The status register (0AH) is 8 bits wide and contains, a
carry flag (C), an auxiliary carry flag (AC), a zero flag (Z),
an overflow flag (OV), a power down flag (PDF), and a
Watchdog time-out flag (TO). It also records the status information and controls the operation sequence. Except
for the TO and PDF flags, bits in the status register can be
altered by instructions similar to other registers. Data
written into the status register does not alter the TO or
PDF flags. Operations related to the status register, however, may yield different results from those intended. The
TO and PDF flags can only be changed by a Watchdog
Timer overflow, chip power-up, or clearing the Watchdog
Timer and executing the ²HALT² instruction.
All these kinds of interrupts have a wake-up capability.
As an interrupt is serviced, a control transfer occurs by
pushing the program counter onto the stack, followed by
a branch to a subroutine at specified location in the program memory. Only the program counter is pushed onto
the stack. If the contents of the register or status register
(STATUS) are altered by the interrupt service program
which corrupts the desired control sequence, the contents should be saved in advance.
The Z, OV, AC, and C flags reflect the status of the latest
operations. On entering the interrupt sequence or exe-
Bit No.
Label
Function
0
C
C is set if an operation results in a carry during an addition operation or if a borrow does not
take place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate through carry instruction.
1
AC
AC is set if an operation results in a carry out of the low nibbles in addition or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
2
Z
Z is set if the result of an arithmetic or logic operation is zero; otherwise Z is cleared.
3
OV
OV is set if an operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
4
PDF
PDF is cleared by system power-up or executing the ²CLR WDT² instruction. PDF is set by
executing the ²HALT² instruction.
5
TO
TO is cleared by system power-up or executing the ²CLR WDT² or ²HALT² instruction. TO is
set by a WDT time-out.
6, 7
¾
Unused bit, read as ²0²
Status (0AH) Register
Rev. 1.00
9
April 23, 2008
HT46RU232
caused by a timer overflow. After the interrupt is enabled, and the stack is not full, and the T0F bit is set, a
subroutine call to location 08H occurs. The related interrupt request flag (T0F) is reset, and the EMI bit is
cleared to disable further maskable interrupts.
The trigger source of interrupt vector 04H could be an
external interrupt or an end of A/D conversion, which is
determined by a configuration option. If interrupt trigger
source is from A/D (not from INT0 pin), the option of trigger edge (INT) doesn¢t work and interrupt occurs only
when A/D conversion is completed when EADI and EMI
are enabled.
The Timer/Event Counter 1 and Timer/Event Counter 2
operates in the same manner, The Timer/Event Counter
1 related interrupt request flag is T1F, bit 6 of the INTC0
register, and its subroutine call location is 0CH. The
Timer/Event Counter 2 related interrupt request flags
are MFF, bit 6 of the INTC1 register, and T2F, and its
subroutine call location is 018H. The related interrupt request flags, T1F and T2F, will be reset and the EMI bit
cleared to disable further interrupts.
External interrupts are triggered by a high to low transition of INT and the related interrupt request flag (EIF; bit
4 of INTC0) will be set. When the interrupt is enabled,
the stack is not full and the external interrupt is active, a
subroutine call to location 04H will occur. The interrupt
request flag (EIF) and EMI bits will be cleared to disable
other interrupts.
The UART Bus interrupt is initialized by setting the
UART Bus interrupt request flag, URF; bit 5 of the
INTC1 register, caused by transmit data register empty
(TXIF), received data available(RXIF), transmission idle
(TIDLE), Over run error (OERR) or Address detected.
When the interrupt is enabled, the stack is not full and
the TXIF, RXIF, TIDLE, OERR bit is set or an address is
detected, a subroutine call to location 014H will occur.
The related interrupt request flag, URF, will be reset and
the EMI bit cleared to disable further interrupts.
The A/D converter interrupt is initialized by setting the
A/D converter request flag (ADF; bit 4 of INTC0),
caused by an end of A/D conversion. When the interrupt
is enabled, the stack is not full and the ADF is set, a subroutine call to location 04H will occur. The related interrupt request flag (ADF) will be reset and the EMI bit
cleared to disable further interrupts.
The internal Timer/Event Counter 0 interrupt is initialized by setting the Timer/Event Counter 0 interrupt request flag (T0F; bit 5 of INTC0), which is normally
Bit No.
Label
0
EMI
Controls the master (global) interrupt (1= enabled; 0= disabled)
Function
1
EEI or EADI
Controls the external interrupt (1= enabled; 0= disabled) or
Controls the A/D conversion interrupt (1= enabled; 0= disabled)
2
ET0I
Controls the Timer/Event Counter 0 interrupt (1= enabled; 0= disabled)
3
ET1I
Controls the Timer/Event Counter 1 interrupt (1= enabled; 0= disabled)
4
EIF or ADF
External interrupt request flag or A/D conversion interrupt request flags.
(1= active; 0= inactive)
5
T0F
Internal Timer/Event Counter 0 request flag (1= active; 0= inactive)
6
T1F
Internal Timer/Event Counter 1 request flag (1= active; 0= inactive)
7
¾
For test mode used only.
Must be written as ²0²; otherwise may result in unpredictable operation.
INTC0 (0BH) Register
Bit No.
Label
0
EURI
Function
1
EHI
2
ET2I
3
¾
4
URF
UART bus interrupt request flag (1= active; 0= inactive)
5
HIF
I2C Bus interrupt request flag (1= active; 0= inactive)
6
T2F
Internal Timer/Event Counter 2 request flag (1= active; 0= inactive)
7
¾
Control the UART bus interrupt (1= enabled; 0=disabled)
Control the I2C Bus interrupt (1= enabled; 0= disabled)
Controls the Timer/Event Counter 2 interrupt (1= enabled; 0= disabled)
Unused bit, read as ²0²
Unused bit, read as ²0²
INTC1 (1EH) Register
Rev. 1.00
10
April 23, 2008
HT46RU232
The I2C Bus interrupt is initialized by setting the I2C Bus interrupt request flag (HIF; bit 5 of INTC1), caused by a
slave address match (HAAS=²1²) or one byte of data
transfer is completed. When the interrupt is enabled, the
stack is not full and the HIF bit is set, a subroutine call to
location 14H will occur. The related interrupt request flag
(HIF) will be reset and the EMI bit cleared to disable further
interrupts.
Oscillator Configuration
There are two oscillator circuits in the microcontroller.
V
O S C 1
Priority
Vector
1
04H
Timer/Event Counter 0 Overflow
2
08H
Timer/Event Counter 1 Overflow
3
0CH
UART Bus Interrupt
4
10H
I2C Bus Interrupt
5
14H
Timer/Event Counter 2 Overflow
6
18H
O S C 1
O S C 2
/4
R C
O s c illa to r
System Oscillator
Both are designed for system clocks, namely the RC oscillator and the Crystal oscillator, which are determined
by the option. No matter what oscillator type is selected,
the signal provides the system clock. The HALT mode
stops the system oscillator and ignores an external signal to conserve power.
If an RC oscillator is used, an external resistor between
OSC1 and VSS is required and the resistance must
range from 30kW to 750kW. The system clock, divided
by 4, is available on OSC2 with pull-high resistor, which
can be used to synchronize external logic. The RC oscillator provides the most cost effective solution. However, the frequency of oscillation may vary with VDD,
temperatures and the chip itself due to process variations. It is, therefore, not suitable for timing sensitive
operations where an accurate oscillator frequency is
desired.
If the Crystal oscillator is used, a crystal across OSC1
and OSC2 is needed to provide the feedback and phase
shift required for the oscillator, and no other external
components are required. Instead of a crystal, a resonator can also be connected between OSC1 and OSC2 to
get a frequency reference, but two external capacitors in
OSC1 and OSC2 are required (If the oscillating frequency is less than 1MHz).
The Timer/Event Counter 0/1 interrupt request flag (T0F,
T1F), external interrupt request flag (EIF), A/D converter
request flag (ADF), the I2C Bus interrupt request flag
(HIF), enable timer/event counter bit (ET0I, ET1I), enable external interrupt bit (EEI), enable A/D converter interrupt bit (EADI), enable I2C Bus interrupt bit (EHI) and
enable master interrupt bit (EMI) constitute an interrupt
control register 0 (INTC0) and an interrupt control register 1 (INTC1) which are located at 0BH and 1EH in the
data memory. EMI, EEI, ET0I, ET1I, EADI, EHI are used
to control the enabling/disabling of interrupts. These bits
prevent the requested interrupt from being serviced.
Once the interrupt request flags (T0F, T1F, EIF, ADF,
HIF) are set, they will remain in the INTC0 and INTC1
register until the interrupts are serviced or cleared by a
software instruction.
The WDT oscillator is a free running on-chip RC oscillator,
and no external components are required. Even if the system enters the power down mode, the system clock is
stopped, but the WDT oscillator still works with a period of
approximately 65ms at 5V. The WDT oscillator can be disabled by option to conserve power.
Watchdog Timer - WDT
The WDT clock source is implemented by a dedicated
RC oscillator (WDT oscillator) or instruction clock (system clock divided by 4) decided by options. This timer is
designed to prevent a software malfunction or sequence
jumping to an unknown location with unpredictable results. The watchdog timer can be disabled by a option. If
the watchdog timer is disabled, all the executions related to the WDT result in no operation.
It is recommended that a program does not use the
²CALL subroutine² within the interrupt subroutine. Interrupts often occur in an unpredictable manner or need to
be serviced immediately in some applications. If only one
stack is left and enabling the interrupt is not well controlled, the original control sequence will be damaged
once the ²CALL² operates in the interrupt subroutine.
Rev. 1.00
Y S
C r y s ta l O s c illa to r
Interrupts, occurring in the interval between the rising
edges of two consecutive T2 pulses, will be serviced on
the latter of the two T2 pulses, if the corresponding interrupts are enabled. In the case of simultaneous requests
the following table shows the priority that is applied.
These can be masked by resetting the EMI bit.
Interrupt Source
4 7 0 p F
fS
O S C 2
During the execution of an interrupt subroutine, other interrupt acknowledgments are held until the ²RETI² instruction is executed or the EMI bit and the related
interrupt control bit are set to 1 (of course, if the stack is
not full). To return from the interrupt subroutine, ²RET² or
²RETI² may be invoked. RETI will set the EMI bit to enable an interrupt service, but RET will not.
External Interrupt or
A/D Conversion
D D
Once an internal WDT oscillator (RC oscillator with period 65ms at 5V normally) is selected, it is divided by
212~215 (by option to get the WDT time-out period). The
WDT time-out minimum period is 300ms~600ms. This
11
April 23, 2008
HT46RU232
S y s te m
C lo c k /4
M a s k
o p tio n
s e le c t
fs
D iv id e r
fs/2
8
W D T
O S C
W D T P r e s c a le r
M a s k O p tio n
W D T C le a r
C K
R
T
C K
R
T
T im e
1 5
/fS
2 1 4/fS
1 3
2 /fS
2 1 2/fS
2
-o
~
~
~
~
u t
2 1
2 1
2 1
2 1
6
5
R e s e t
/fS
/fS
4
/fS
3
/fS
Watchdog Timer
time-out period may vary with temperature, VDD and
process variations. By selection from the WDT option,
longer time-out periods can be realized. If the WDT
time-out is selected 215, the maximum time-out period is
divided by 215~216about 2.1s~4.3s.
· The WDT will be cleared and start recounting (if the
If the WDT oscillator is disabled, the WDT clock may still
come from the instruction clock and operate in the same
manner except that in the HALT state the WDT may stop
counting and lose its protecting purpose. In this situation
the logic can only be restarted by external logic. If the
device operates in a noisy environment, using the
on-chip RC oscillator (WDT OSC) is strongly recommended, since the HALT will stop the system clock.
The system quits the HALT mode by an external reset,
an interrupt, an external falling edge signal on port A or a
WDT overflow. An external reset causes a device initialization and the WDT overflow performs a ²warm reset².
After examining the TO and PDF flags, the reason for
chip reset can be determined. The PDF flag is cleared
by system power-up or by executing the ²CLR WDT² instruction and is set when executing the ²HALT² instruction. On the other hand, the TO flag is set if the WDT
time-out occurs, and causes a wake-up that only resets
the program counter and SP; and leaves the others in
their original status.
WDT clock source is from the WDT oscillator or the
real time clock)
· All of the I/O ports maintain their original status
· The PDF flag is set and the TO flag is cleared
The WDT overflow under normal operation will initialize
²chip reset² and set the status bit TO. Whereas in the
HALT mode, the overflow will initialize a ²warm reset²
only the program counter and stack pointer are reset to
zero. To clear the contents of WDT, three methods are
adopted; external reset (a low level to RES), software instructions, or a HALT instruction. The software instructions include CLR WDT and the other set CLR WDT1
and CLR WDT2. Of these two types of instruction, only
one can be active depending on the option - ²CLR WDT
times selection option². If the ²CLR WDT² is selected (i.e.
CLRWDT times equal one), any execution of the CLR
WDT instruction will clear the WDT. In case ²CLR
WDT1² and ²CLR WDT2² are chosen (i.e. CLRWDT
times equal two), these two instructions must be executed to clear the WDT; otherwise, the WDT may reset
the chip because of time-out.
Power Down Operation - HALT
The port A wake-up and interrupt methods can be considered as a continuation of normal execution. Each bit
in port A can be independently selected to wake up the
device by the option. Awakening from an I/O port stimulus, the program will resume execution of the next instruction. If it is awakening from an interrupt, two
sequences may occur. If the related interrupt is disabled
or the interrupt is enabled but the stack is full, the program will resume execution at the next instruction. But if
the interrupt is enabled and the stack is not full, the regular interrupt response takes place. When an interrupt request flag is set to ²1² before entering the HALT mode,
the wake-up function of the related interrupt will be disabled. If wake-up event occurs, it takes 1024 fSYS (system clock period) to resume normal operation. In other
words, a dummy period is inserted after wake-up. If the
wake-up results from an interrupt acknowledgment, the
actual interrupt subroutine execution is delayed by more
than one cycle. However, if the wake-up results in the
next instruction execution, this will be executed performed immediately after the dummy period is finished.
The HALT mode is initialized by the ²HALT² instruction
and results in the following...
To minimize power consumption, all the I/O pins should
be carefully managed before entering the HALT status.
If the WDT time-out period is selected fs/212 (option), the
WDT time-out period ranges from fs/212~fs/213, since the
²CLR WDT² or ²CLR WDT1² and ²CLR WDT2²
instructions only clear the last two stages of the WDT.
· The system oscillator turned off but the WDT oscillator
keeps running (if the WDT oscillator or the real time
clock is selected).
· The contents of the on-chip RAM and registers remain
unchanged
Rev. 1.00
12
April 23, 2008
HT46RU232
Reset
V D D
There are three ways in which a reset may occur:
R E S
· RES reset during normal operation
· WDT time-out reset during normal operation
C h ip
The WDT time-out during HALT differs from other chip
reset conditions, for it can perform a ²warm reset² that
resets only the program counter and stack pointer,
leaves the other circuits at their original state. Some registers remain unaffected during any other reset conditions. Most registers are reset to the ²initial condition²
when the reset conditions are met. Examining the
PDF and TO flags, the program can distinguish between
different ²chip resets².
PDF
0
0
RES reset during power-up
u
RES reset during normal operation
0
1
RES wake-up HALT
1
u
WDT time-out during normal operation
1
1
WDT wake-up HALT
V
1 0 0 k W
R E S
000H
Interrupt
Disable
Prescaler, Divider
Cleared
WDT
Clear. After master reset,
WDT begins counting
Timer/event Counter
Off
Input/output Ports
Input mode
Stack Pointer
Points to the top of the stack
O S C 1
W a rm
Note:
0 .1 m F
H i-n o is e
R e s e t
C ir c u it
Most applications can use the Basic Reset Circuit as shown, however for applications with
extensive noise, it is recommended to use the
Hi-noise Reset Circuit.
Timer/Event Counter
Two Timer/Event Counters (TMR0,TMR1) are implemented in the microcontroller. The timer/event counter 0
contains an 16-bit programmable count-up counter and
the clock may come from an external source or an internal clock source. An internal clock source comes from
fSYS. The timer/event counter 1 contains an 16-bit programmable count-up counter and the clock may come
from an external source or an internal clock source. An
internal clock source comes from fSYS/4. The external
clock input allows the user to count external events,
measure time intervals or pulse widths, or to generate
an accurate time base.
There are six registers related to the Timer/Event Counter 0; TMR0H (0CH), TMR0L (0DH), TMR0C (0EH) and
the Timer/Event Counter 1; TMR1H (0FH), TMR1L
(10H), TMR1C (11H). Writing TMR0L (TMR1L) will only
put the written data to an internal lower-order byte buffer
(8-bit) and writing TMR0H (TMR1H) will transfer the
specified data and the contents of the lower-order byte
buffer to TMR0H (TMR1H) and TMR0L (TMR1L) registers, respectively. The Timer/Event Counter 1/0 preload
register is changed by each writing TMR0H (TMR1H)
operations. Reading TMR0H (TMR1H) will latch the
contents of TMR0H (TMR1H) and TMR0L (TMR1L)
counters to the destination and the lower-order byte
buffer, respectively. Reading the TMR0L (TMR1L) will
read the contents of the lower-order byte buffer. The
TMR0C (TMR1C) is the Timer/Event Counter 0 (1) control register, which defines the operating mode, counting
enable or disable and an active edge.
R e s e t
E x te rn a l
C o ld
R e s e t
S S T
1 0 - b it R ip p le
C o u n te r
P o w e r - o n D e te c tio n
Reset Configuration
Rev. 1.00
R E S
1 0 k W
Reset Circuit
Awaking from the HALT state or system power up an
SST delay is added. An extra SST delay is added during
power up period, and any wake-up from HALT may enable only the SST delay. The functional unit chip reset
status are shown below.
Program Counter
D D
1 0 0 k W
0 .1 m F
To guarantee that the system oscillator is started and
stabilized, the SST (System Start-up Timer) provides an
extra-delay of 1024 system clock pulses when the system awakes from the HALT state or during power up.
H A L T
V
D D
0 .0 1 m F
Note: ²u² stands for ²unchanged²
R E S
P D
R e s e t
B a s ic
R e s e t
C ir c u it
u
W D T
+ tO
Reset Timing Chart
RESET Conditions
W D T
T im e - o u t
R e s e t
S T
S S T T im e - o u t
· RES reset during HALT
TO
tS
13
April 23, 2008
HT46RU232
The registers states are summarized in the following table.
Register
Reset
(Power On)
WDT Time-out
RES Reset
(Normal Operation) (Normal Operation)
RES Reset
(HALT)
WDT Time-out
(HALT)*
MP0
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
MP1
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
ACC
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
000H
000H
000H
000H
000H
TBLP
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
TBLH
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
uuuu uuuu
Program
Counter
STATUS
--00 xxxx
--1u uuuu
--uu uuuu
--01 uuuu
--11 uuuu
INTC0
-000 0000
-000 0000
-000 0000
-000 0000
-uuu uuuu
TMR0H
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TMR0L
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TMR0C
00-0 1000
00-0 1000
00-0 1000
00-0 1000
uu-u uuuu
TMR1H
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TMR1L
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
TMR1C
00-0 1---
00-0 1---
00-0 1---
00-0 1---
uu-u u---
PA
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PAC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PB
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PBC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PCC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PD
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PDC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PWM0
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
PWM1
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
PWM2
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
PWM3
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
INTC1
--00 --00
--00 --00
--00 --00
--00 --00
--uu --uu
HADR
xxxx xxx-
xxxx xxx-
xxxx xxx-
xxxx xxx-
uuuu uuu-
HCR
0--0 0---
0--0 0---
0--0 0---
0--0 0---
u--u u---
HSR
100- -0-1
100- -0-1
100- -0-1
100- -0-1
uuuu uuuu
HDR
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
ADRL
xxxx ----
xxxx ----
xxxx ----
xxxx ----
uuuu ----
ADRH
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADCR
0100 0000
0100 0000
0100 0000
0100 0000
uuuu uuuu
ACSR
1--- --00
1--- --00
1--- --00
1--- --00
u--- --uu
PF
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
PFC
1111 1111
1111 1111
1111 1111
1111 1111
uuuu uuuu
TMR2
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
Rev. 1.00
14
April 23, 2008
HT46RU232
WDT Time-out
RES Reset
(Normal Operation) (Normal Operation)
Reset
(Power On)
Register
RES Reset
(HALT)
WDT Time-out
(HALT)*
TMR2C
00-0 1000
00-0 1000
00-0 1000
00-0 1000
uu-u uuuu
USR
0000 1011
0000 1011
0000 1011
0000 1011
uuuu uuuu
UCR1
0000 00x0
0000 00x0
0000 00x0
0000 00x0
uuuu uuuu
UCR2
0000 0000
0000 0000
0000 0000
0000 0000
uuuu uuuu
TXR/RXR
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
BRG
xxxx xxxx
xxxx xxxx
xxxx xxxx
xxxx xxxx
uuuu uuuu
²*² stands for warm reset
²u² stands for unchanged
²x² stands for unknown
Note:
P W M
(6 + 2 ) o r (7 + 1 )
C o m p a re
fS
T o P D 0 /P D 1 /P D 2 /P D 3 C ir c u it
D a ta B u s
8 - s ta g e P r e s c a le r
Y S
f IN
8 -1 M U X
T 0 P S C 2 ~ T 0 P S C 0
L o w B y te
B u ffe r
T
T 0 M 1
T 0 M 0
T M R 0
1 6 - B it
P r e lo a d R e g is te r
T 0 E
P u ls e W id th
M e a s u re m e n t
M o d e C o n tro l
T 0 M 1
T 0 M 0
T 0 O N
H ig h B y te
R e lo a d
O v e r flo w
L o w B y te
to In te rru p t
1 6 - B it T im e r /E v e n t C o u n te r
P F D 0
Timer/Event Counter 0
D a ta B u s
fS
Y S
/4
f IN
L o w B y te
B u ffe r
T
T 1 M 1
T 1 M 0
T M R 1
1 6 - B it
P r e lo a d R e g is te r
T 1 E
T 1 M 1
T 1 M 0
T 1 O N
P u ls e W id th
M e a s u re m e n t
M o d e C o n tro l
H ig h B y te
L o w
R e lo a d
O v e r flo w to In te r r u p t
B y te
1 6 - B it T im e r /E v e n t C o u n te r
P F D 1
Timer/Event Counter 1
fS
Y S
8 - s ta g e P r e s c a le r
f IN
8 -1 M U X
T 2 P S C 2 ~ T 2 P S C 0
(1 /1 ~ 1 /1 2 8 )
D a ta B u s
T
T 2 M 1
T 2 M 0
T M R 2
8 - B it T im e r /E v e n t
C o u n te r P r e lo a d R e g is te r
R e lo a d
T 2 E
T 2 M 1
T 2 M 0
T 2 O N
8 - B it T im e r /E v e n t
C o u n te r (T M R 2 )
P u ls e W id th
M e a s u re m e n t
M o d e C o n tro l
O v e r flo w
to In te rru p t
Timer/Event Counter 2
Rev. 1.00
15
April 23, 2008
HT46RU232
P F D 0
P F D 1
M
U
1 /2
X
P F D
P A 3 D a ta C T R L
P F D
S o u r c e O p tio n
PFD Source Option
The T0M0/T0M1 (TMR0C), T1M0/T1M1 (TMR1C) and
T2M0/T2M1 (TMR2C) bits define the operation mode.
The event count mode is used to count external events,
which means that the clock source is from an external
(TMR0, TMR1, TMR2) pin. The timer mode functions as
a normal timer with the clock source coming from the internal selected clock source. Finally, the pulse width
measurement mode can be used to count the high or
low level duration of the external signal (TMR0, TMR1,
TMR2), and the counting is based on the internal selected clock source.
reset by instructions. The overflow of the Timer/Event
Counter 0/1 is one of the wake-up sources and can also
be applied to a PFD (Programmable Frequency Divider)
output at PA3 by options. Only one PFD (PFD0 or
PFD1) can be applied to PA3 by options. If PA3 is set as
PFD output, there are two types of selections; One is
PFD0 as the PFD output, the other is PFD1 as the PFD
output. PFD0, PFD1 are the timer overflow signals of
the Timer/Event Counter 0, Timer/Event Counter 1 respectively. No matter what the operation mode is, writing a 0 to ET0I or ET1I disables the related interrupt
service. When the PFD function is selected, executing
²SET [PA].3² instruction to enable PFD output and executing ²CLR [PA].3² instruction to disable PFD output.
In the event count or timer mode, the timer/event counter starts counting at the current contents in the
timer/event counter and ends at FFFFH. Once an overflow occurs, the counter is reloaded from the timer/event
counter preload register, and generates an interrupt request flag.
In the case of timer/event counter OFF condition, writing
data to the timer/event counter preload register also reloads that data to the timer/event counter. But if the
timer/event counter is turn on, data written to the
timer/event counter is kept only in the timer/event counter preload register. The timer/event counter still continues its operation until an overflow occurs.
In the pulse width measurement mode with the values of
the T0ON/T1ON/T2ON and T0E/T1E/T2E bits equal to
1, after the TMR0, TMR1, TMR2 has received a transient from low to high (or high to low if the T0E/T1E/T2E
bit is ²0²), it will start counting until the TMR0, TMR1,
TMR2 returns to the original level and resets the
T0ON/T1ON/ T2ON. The measured result remains in
the timer/event counter even if the activated transient
occurs again. In other words, only 1-cycle measurement
can be made until the T0ON/T1ON/T2ON is set. The cycle measurement will re-function as long as it receives
further transient pulse. In this operation mode, the
timer/event counter begins counting not according to
the logic level but to the transient edges. In the case of
counter overflows, the counter is reloaded from the
timer/event counter register and issues an interrupt request, as in the other two modes, i.e., event and timer
modes.
When the timer/event counter (reading TMR0/TMR1/
TMR2) is read, the clock is blocked to avoid errors, as
this may results in a counting error. Blocking of the clock
should be taken into account by the programmer. It is
strongly recommended to load a desired value into the
TMR0/TMR1/TMR2 register first, before turning on the
related timer/event counter, for proper operation since
the initial value of TMR0/TMR1/TMR2 is unknown. Due
to the timer/event scheme, the programmer should pay
special attention on the instruction to enable then disable the timer for the first time, whenever there is a need
to use the timer/event function, to avoid unpredictable
result. After this procedure, the timer/event function can
be operated normally.
The bit0~bit2 of the TMR0C/TMR2C can be used to define the pre-scaling stages of the internal clock sources
of timer/event counter. The definitions are as shown.
The overflow signal of timer/event counter can be used
to generate the PFD signal. The timer prescaler is also
used as the PWM counter.
To enable the counting operation, the Timer ON bit
should be set to 1. In the pulse width measurement
mode, the T0ON/T1ON/T2ON is automatically cleared
after the measurement cycle is completed. But in the
other two modes, the T0ON/T1ON/T2ON can only be
Rev. 1.00
16
April 23, 2008
HT46RU232
Bit No.
Label
Function
T0PSC0
T0PSC1
T0PSC2
Defines the prescaler stages, T0PSC2, T0PSC1, T0PSC0=
000: fINT=fSYS
001: fINT=fSYS/2
010: fINT=fSYS/4
011: fINT=fSYS/8
100: fINT=fSYS/16
101: fINT=fSYS/32
110: fINT=fSYS/64
111: fINT=fSYS/128
3
T0E
Defines the TMR0 active edge of the timer/event counter:
In Event Counter Mode (T0M1,T0M0)=(0,1):
1:count on falling edge;
0:count on rising edge
In Pulse Width measurement mode (T0M1,T0M0)=(1,1):
1: start counting on the rising edge, stop on the falling edge;
0: start counting on the falling edge, stop on the rising edge
4
T0ON
5
¾
0
1
2
6
7
T0M0
T0M1
Enable/disable timer counting (0=disabled; 1=enabled)
Unused bit, read as ²0²
Defines the operating mode, T0M1, T0M0:
01=Event count mode (external clock)
10=Timer mode (internal clock)
11=Pulse width measurement mode
00=Unused
TMR0C (0EH) Register
Bit No.
Label
0~2
¾
3
T1E
4
T1ON
5
¾
6
7
T1M0
T1M1
Function
Unused bit, read as ²0²
Defines the TMR1 active edge of the timer/event counter:
In Event Counter Mode (T1M1,T1M0)=(0,1):
1:count on falling edge;
0:count on rising edge
In Pulse Width measurement mode (T1M1,T1M0)=(1,1):
1: start counting on the rising edge, stop on the falling edge;
0: start counting on the falling edge, stop on the rising edge
Enable/disable timer counting (0=disabled; 1=enabled)
Unused bit, read as ²0²
Defines the operating mode, T1M1, T1M0:
01=Event count mode (external clock)
10=Timer mode (internal clock)
11=Pulse width measurement mode
00=Unused
TMR1C (11H) Register
Rev. 1.00
17
April 23, 2008
HT46RU232
Bit No.
Label
Function
T2PSC0
T2PSC1
T2PSC2
Defines the prescaler stages, T2PSC2, T2PSC1, T2PSC0=
000: fINT=fSYS
001: fINT=fSYS/2
010: fINT=fSYS/4
011: fINT=fSYS/8
100: fINT=fSYS/16
101: fINT=fSYS/32
110: fINT=fSYS/64
111: fINT=fSYS/128
3
T2E
Defines the TMR2 active edge of the timer/event counter:
In Event Counter Mode (T2M1,T2M0)=(0,1):
1:count on falling edge;
0:count on rising edge
In Pulse Width measurement mode (T2M1,T2M0)=(1,1):
1: start counting on the rising edge, stop on the falling edge;
0: start counting on the falling edge, stop on the rising edge
4
T2ON
0
1
2
¾
5
6
7
T2M0
T2M1
Enables/disables the timer counting (0=disable; 1=enable)
Unused bit, read as ²0²
Defines the operating mode, T2M1, T2M0:
01=Event count mode (external clock)
10=Timer mode (internal clock)
11=Pulse width measurement mode
00=Unused
TMR2C (2EH) Register
After a chip reset, these input/output lines remain at high
levels or floating state (depends on pull-high options).
Each bit of these input/output latches can be set or
cleared by ²SET [m].i² and ²CLR [m].i² (m=12H, 14H,
16H 18H or 28H) instructions.
Input/Output Ports
There are 40 bidirectional input/output lines in the
microcontroller, labeled as PA, PB, PC, PD and PF,
which are mapped to the data memory of [12H], [14H],
[16H], [18H] and [28H] respectively. All of these I/O ports
can be used for input and output operations. For input
operation, these ports are non-latching, that is, the inputs must be ready at the T2 rising edge of instruction
²MOV A,[m]² (m=12H, 14H, 16H, [18H] or 28H). For output operation, all the data is latched and remains unchanged until the output latch is rewritten.
Some instructions first input data and then follow the
output operations. For example, ²SET [m].i², ²CLR
[m].i², ²CPL [m]², ²CPLA [m]² read the entire port states
into the CPU, execute the defined operations
(bit-operation), and then write the results back to the
latches or the accumulator.
Each I/O line has its own control register (PAC, PBC,
PCC, PDC, PFC) to control the input/output configuration. With this control register, CMOS output or Schmitt
trigger input with or without pull-high resistor structures
can be reconfigured dynamically under software control.
To function as an input, the corresponding latch of the
control register must write ²1². The input source also depends on the control register. If the control register bit is
²1², the input will read the pad state. If the control register bit is ²0², the contents of the latches will move to the
internal bus. The latter is possible in the ²read-modifywrite² instruction.
Each line of port A has the capability of waking-up the
device. Each I/O port has a pull-high option. Once the
pull-high option is selected, the I/O port has a pull-high
resistor, otherwise, there¢s none. Take note that a
non-pull-high I/O port operating in input mode will cause
a floating state.
The PA3 and PA5 are pin-shared with the PFD and INT
pins respectively. If the PFD option is selected, the output signal in output mode of PA3 will be the PFD signal
generated by timer/event counter overflow signal. The
input mode always remain in its original functions. Once
the PFD option is selected, the PFD output signal is controlled by PA3 data register only. Writing ²1² to PA3 data
register will enable the PFD output function and writing 0
will force the PA3 to remain at ²0². The I/O functions of
PA3 are shown below.
For output function, CMOS is the only configuration.
These control registers are mapped to locations 13H,
15H, 17H, 19H and 29H.
Rev. 1.00
18
April 23, 2008
HT46RU232
I/O
I/P
Mode (Normal)
Logical
Input
PA3
Note:
O/P
(Normal)
I/P
(PFD)
O/P
(PFD)
Logical
Output
Logical
Input
PFD
(Timer on)
It is recommended that unused or not bonded out I/O
lines should be set as output pins by software instruction
to avoid consuming power under input floating state.
PWM
The PFD frequency is the timer/event counter
overflow frequency divided by 2.
The microcontroller provides 4 channels (6+2)/(7+1) (depends on options) bits PWM output shared with
PD0/PD1/PD2/PD3. The PWM channels have their data
registers denoted as PWM0 (1AH), PWM1 (1BH), PWM2
(1CH) and PWM3 (1DH). The frequency source of the
PWM counter comes from fSYS. The PWM registers are
four 8-bit registers. The waveforms of PWM outputs are as
shown. Once the PD0/PD1/PD2/PD3 are selected as the
PWM outputs and the output function of
PD0/PD1/PD2/PD3 are enabled (PDC.0/PDC.1/
PDC.2/PDC.3 =²0²), writing ²1² to PD0/PD1/PD2/PD3
data register will enable the PWM output function and writing ²0² will force the PD0/PD1/PD2/PD3 to stay at ²0².
The PB can also be used as A/D converter inputs. The
A/D function will be described later. There is a PWM
function shared with PD0/PD1/PD2/PD3. If the PWM
function is enabled, the PWM0/PWM1/PWM2/PWM3
signal will appear on PD0/PD1/PD2/PD3 (if PD0/PD1/
PD2/PD3 is operating in output mode). The I/O functions of PD0/PD1/PD2/PD3 are as shown.
I/O
Mode
PD0~
PD3
I/P
O/P
(Normal) (Normal)
Logical
Input
Logical
Output
I/P
(PWM)
O/P
(PWM)
Logical
Input
PWM0~
PWM3
V
C o n tr o l B it
D a ta B u s
W r ite C o n tr o l R e g is te r
Q
D
C K
D D
P u ll- h ig h
O p tio n
Q
S
C h ip R e s e t
P C 0 /T X
R e a d C o n tr o l R e g is te r
W r ite D a ta R e g is te r
D a ta B it
Q
D
C K
Q
S
M
F ro m
U A R T T X
M
R e a d D a ta R e g is te r
U
U
X
U A R T E N
X
& T X E N
PC0/TX Input/Output Ports
V
C o n tr o l B it
D a ta B u s
W r ite C o n tr o l R e g is te r
Q
D
C K
D D
P u ll- h ig h
O p tio n
Q
S
C h ip R e s e t
R e a d C o n tr o l R e g is te r
W r ite D a ta R e g is te r
P C 1 /R X
D a ta B it
Q
D
C K
S
Q
M
R e a d D a ta R e g is te r
U
X
T o U A R T R X
PC1/RX Input/Output Ports
Rev. 1.00
19
April 23, 2008
HT46RU232
V
C o n tr o l B it
W r ite C o n tr o l R e g is te r
P U
Q
D
D a ta B u s
C K
D D
P A
P A
P A
P A
P A
P A
P B
P C
P D
P D
P D
P D
P D
P F
Q
S
C h ip R e s e t
R e a d C o n tr o l R e g is te r
D a ta B it
Q
D
Q
C K
W r ite D a ta R e g is te r
S
M
M
[P A 3 , P F D ]
o r [P D 0 ,P W M 0 ]
R e a d D a ta R e g is te r
o r [P D 1 ,P W M 1 ]
U
o r [P D 3 ,P W M 3 ]
4
5 /IN
6 /S
7 /S
0 /A
2 ~ P
0 /P
1 /P
2 /P
3 /P
4 ~ P
0 ~ P
T
D A
C L
N 0 ~
C 7
W M
W M
W M
W M
D 7
F 7
0
P B 7 /A N 7
1
2
3
X
E N (P F D o r
P W M 0 ~ P W M 3 )
X
S y s te m W a k e -u p
( P A o n ly )
o r [P D 2 ,P W M 2 ]
U
0 ~ P A 2
3 /P F D
O P 0 ~ O P 7
IN T fo r P A 5 O n ly
PC2~PC7 Input/Output Ports
A (6+2) bits mode PWM cycle is divided into four modulation cycles (modulation cycle 0~modulation cycle 3).
Each modulation cycle has 64 PWM input clock period.
In a (6+2) bit PWM function, the contents of the PWM
register is divided into two groups. Group 1 of the PWM
register is denoted by DC which is the value of
PWM.7~PWM.2. The group 2 is denoted by AC which is
the value of PWM.1~PWM.0.
A (7+1) bits mode PWM cycle is divided into two modulation cycles (modulation cycle0~modulation cycle 1).
Each modulation cycle has 128 PWM input clock period.
In a (7+1) bits PWM function, the contents of the PWM
register is divided into two groups. Group 1 of the PWM
register is denoted by DC which is the value of
PWM.7~PWM.1. The group 2 is denoted by AC which is
the value of PWM.0.
In a (6+2) bits mode PWM cycle, the duty cycle of each
modulation cycle is shown in the table.
Parameter
Modulation cycle i
(i=0~3)
fS
Y S
AC (0~3)
Duty Cycle
i<AC
DC+1
64
i³AC
DC
64
In a (7+1) bits mode PWM cycle, the duty cycle of each
modulation cycle is shown in the table.
Parameter
AC (0~1)
Duty Cycle
i<AC
DC+1
128
i³AC
DC
128
Modulation cycle i
(i=0~1)
/2
[P W M ] = 1 0 0
P W M
2 5 /6 4
2 5 /6 4
2 5 /6 4
2 5 /6 4
2 5 /6 4
2 6 /6 4
2 5 /6 4
2 5 /6 4
2 5 /6 4
2 6 /6 4
2 6 /6 4
2 6 /6 4
2 5 /6 4
2 5 /6 4
2 6 /6 4
2 6 /6 4
2 6 /6 4
2 5 /6 4
2 6 /6 4
[P W M ] = 1 0 1
P W M
[P W M ] = 1 0 2
P W M
[P W M ] = 1 0 3
P W M
2 6 /6 4
P W M
m o d u la tio n p e r io d : 6 4 /fS
M o d u la tio n c y c le 0
Y S
M o d u la tio n c y c le 1
P W M
M o d u la tio n c y c le 2
c y c le : 2 5 6 /fS
M o d u la tio n c y c le 3
M o d u la tio n c y c le 0
Y S
(6+2) PWM Mode
Rev. 1.00
20
April 23, 2008
HT46RU232
fS
Y S
/2
[P W M ] = 1 0 0
P W M
5 0 /1 2 8
5 0 /1 2 8
5 0 /1 2 8
5 1 /1 2 8
5 0 /1 2 8
5 1 /1 2 8
5 1 /1 2 8
5 1 /1 2 8
5 1 /1 2 8
5 1 /1 2 8
5 2 /1 2 8
[P W M ] = 1 0 1
P W M
[P W M ] = 1 0 2
P W M
[P W M ] = 1 0 3
P W M
5 2 /1 2 8
P W M
m o d u la tio n p e r io d : 1 2 8 /fS
Y S
M o d u la tio n c y c le 0
M o d u la tio n c y c le 1
P W M
c y c le : 2 5 6 /fS
M o d u la tio n c y c le 0
Y S
(7+1) PWM Mode
The modulation frequency, cycle frequency and cycle
duty of the PWM output signal are summarized in the
following table.
PWM
Modulation Frequency
fSYS/64 for (6+2) bits mode
fSYS/128 for (7+1) bits mode
ADCR) is end of A/D conversion flag. Check this bit to
know when A/D conversion is completed. The START
bit of the ADCR is used to begin the conversion of the
A/D converter. Giving START bit a rising edge and falling edge means that the A/D conversion has started. In
order to ensure the A/D conversion is completed, the
START should remain at ²0² until the EOCB is cleared
to ²0² (end of A/D conversion).
PWM Cycle PWM Cycle
Frequency
Duty
fSYS/256
[PWM]/256
Bit 7 of the ACSR register is used for test purposes only
and must not be used for other purposes by the application program. Bit1 and bit0 of the ACSR register are
used to select the A/D clock source.
A/D Converter
The 8 channels and 12-bit resolution A/D converter are
implemented in this microcontroller. The reference voltage is VDD. The A/D converter contains 4 special registers which are; ADRL (24H), ADRH (25H), ADCR (26H)
and ACSR (27H). The ADRH and ADRL are A/D result
register higher-order byte and lower-order byte and are
read-only. After the A/D conversion is completed, the
ADRH and ADRL should be read to get the conversion
result data. The ADCR is an A/D converter control register, which defines the A/D channel number, analog
channel select, start A/D conversion control bit and the
end of A/D conversion flag. If the users want to start an
A/D conversion, define PB configuration, select the converted analog channel, and give START bit a raising
edge and falling edge (0®1®0). At the end of A/D conversion, the EOCB bit is cleared and an A/D converter
interrupt occurs (if the A/D converter interrupt is enabled). The ACSR is A/D clock setting register, which is
used to select the A/D clock source.
When the A/D conversion has completed, the A/D interrupt request flag will be set. The EOCB bit is set to ²1²
when the START bit is set from ²0² to ²1².
Important Note for A/D initialization:
Special care must be taken to initialize the A/D converter each time the Port B A/D channel selection bits
are modified, otherwise the EOCB flag may be in an undefined condition. An A/D initialization is implemented
by setting the START bit high and then clearing it to zero
within 10 instruction cycles of the Port B channel selection bits being modified. Note that if the Port B channel
selection bits are all cleared to zero then an A/D initialization is not required.
The A/D converter control register is used to control the
A/D converter. The bit2~bit0 of the ADCR are used to
select an analog input channel. There are a total of eight
channels to select. The bit5~bit3 of the ADCR are used
to set PB configurations. PB can be an analog input or
as digital I/O line decided by these 3 bits. Once a PB line
is selected as an analog input, the I/O functions and
pull-high resistor of this I/O line are disabled and the A/D
converter circuit is power on. The EOCB bit (bit6 of the
Rev. 1.00
ACS2
ACS1
ACS0
Analog Channel
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
Analog Input Channel Selection
21
April 23, 2008
HT46RU232
Bit No.
Label
Function
0
1
2
ACS0
ACS1
ACS2
Defines the analog channel select
3
4
5
PCR0
PCR1
PCR2
Defines the port B configuration select. If PCR0, PCR1 and PCR2 are all zero, the ADC circuit is
power off to reduce power consumption
6
EOCB
Indicates end of A/D conversion. (0 = end of A/D conversion)
Each time bits 3~5 change state the A/D should be initialized by issuing a START signal, otherwise the EOCB flag may have an undefined condition. See ²Important note for A/D initialization².
7
START Starts the A/D conversion. (0®1®0= start; 0®1= Reset A/D converter and set EOCB to ²1²)
ADCR (26H) Register
PCR2
PCR1
PCR0
7
6
5
4
3
2
1
0
0
0
0
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
0
0
1
PB7
PB6
PB5
PB4
PB3
PB2
PB1
AN0
0
1
0
PB7
PB6
PB5
PB4
PB3
PB2
AN1
AN0
0
1
1
PB7
PB6
PB5
PB4
PB3
AN2
AN1
AN0
1
0
0
PB7
PB6
PB5
PB4
AN3
AN2
AN1
AN0
1
0
1
PB7
PB6
PB5
AN4
AN3
AN2
AN1
AN0
1
1
0
PB7
PB6
AN5
AN4
AN3
AN2
AN1
AN0
1
1
1
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
Port B Configuration
Bit No.
Label
Function
Selects the A/D converter clock source
00= system clock/2
01= system clock/8
10= system clock/32
11= undefined
0
1
ADCS0
ADCS1
2~6
¾
Unused bit, read as ²0²
7
TEST
For test mode used only
ACSR (27H) Register
Register
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
ADRL
D3
D2
D1
D0
¾
¾
¾
¾
ADRH
D11
D10
D9
D8
D7
D6
D5
D4
Note:
D0~D11 is A/D conversion result data bit LSB~MSB.
ADRL (24H), ADRH (25H) Register
Rev. 1.00
22
April 23, 2008
HT46RU232
The following two programming examples illustrate how to setup and implement an A/D conversion. In the first example, the method of polling the EOCB bit in the ADCR register is used to detect when the conversion cycle is complete,
whereas in the second example, the A/D interrupt is used to determine when the conversion is complete.
Example: using EOCB Polling Method to detect end of conversion
clr
EADI
; disable ADC interrupt
mov
a,00000001B
mov
ACSR,a
; setup the ACSR register to select fSYS/8 as the A/D clock
mov
a,00100000B
; setup ADCR register to configure Port PB0~PB3 as A/D inputs
mov
ADCR,a
; and select AN0 to be connected to the A/D converter
:
:
; As the Port B channel bits have changed the following START
; signal (0-1-0) must be issued within 10 instruction cycles
:
Start_conversion:
clr
START
set
START
; reset A/D
clr
START
; start A/D
Polling_EOC:
sz
EOCB
; poll the ADCR register EOCB bit to detect end of A/D conversion
jmp
polling_EOC
; continue polling
mov
a,ADRH
; read conversion result high byte value from the ADRH register
mov
adrh_buffer,a
; save result to user defined memory
mov
a,ADRL
; read conversion result low byte value from the ADRL register
mov
adrl_buffer,a
; save result to user defined memory
:
:
jmp
start_conversion
; start next A/D conversion
Example: using interrupt method to detect end of conversion
clr
EADI
; disable ADC interrupt
mov
a,00000001B
mov
ACSR,a
; setup the ACSR register to select fSYS/8 as the A/D clock
mov
mov
a,00100000B
ADCR,a
:
; setup ADCR register to configure Port PB0~PB3 as A/D inputs
; and select AN0 to be connected to the A/D converter
; As the Port B channel bits have changed the following START
; signal (0-1-0) must be issued within 10 instruction cycles
:
Start_conversion:
clr
START
set
START
clr
START
clr
ADF
set
EADI
set
EMI
:
:
:
; ADC interrupt service routine
ADC_ISR:
mov
acc_stack,a
mov
a,STATUS
mov
status_stack,a
:
:
mov
a,ADRH
mov
adrh_buffer,a
mov
a,ADRL
mov
adrl_buffer,a
clr
START
set
START
clr
START
:
:
EXIT_INT_ISR:
mov
a,status_stack
mov
STATUS,a
mov
a,acc_stack
reti
Rev. 1.00
; reset A/D
; start A/D
; clear ADC interrupt request flag
; enable ADC interrupt
; enable global interrupt
; save ACC to user defined memory
; save STATUS to user defined memory
; read conversion result high byte value from the ADRH register
; save result to user defined register
; read conversion result low byte value from the ADRL register
; save result to user defined register
; reset A/D
; start A/D
; restore STATUS from user defined memory
; restore ACC from user defined memory
23
April 23, 2008
HT46RU232
M in im u m
o n e in s tr u c tio n c y c le n e e d e d , M a x im u m
te n in s tr u c tio n c y c le s a llo w e d
S T A R T
E O C B
A /D
tA
P C R 2 ~
P C R 0
s a m p lin g tim e
A /D
tA
D C S
0 0 0 B
s a m p lin g tim e
A /D
tA
D C S
1 0 0 B
1 0 0 B
s a m p lin g tim e
D C S
1 0 1 B
0 0 0 B
1 . P B p o rt s e tu p a s I/O s
2 . A /D c o n v e r te r is p o w e r e d o ff
to r e d u c e p o w e r c o n s u m p tio n
A C S 2 ~
A C S 0
0 0 0 B
P o w e r-o n
R e s e t
0 1 0 B
0 0 0 B
0 0 1 B
S ta rt o f A /D
c o n v e r s io n
S ta rt o f A /D
c o n v e r s io n
S ta rt o f A /D
c o n v e r s io n
R e s e t A /D
c o n v e rte r
R e s e t A /D
c o n v e rte r
E n d o f A /D
c o n v e r s io n
1 : D e fin e P B c o n fig u r a tio n
2 : S e le c t a n a lo g c h a n n e l
A /D
N o te :
A /D
tA D
tA
C S
D C
c lo c k m u s t b e fS
= 3 2 tA D
= 7 6 tA D
Y S
/2 , fS
tA D C
c o n v e r s io n tim e
Y S
/8 o r fS
Y S
d o n 't c a r e
R e s e t A /D
c o n v e rte r
E n d o f A /D
c o n v e r s io n
A /D
tA D C
c o n v e r s io n tim e
E n d o f A /D
c o n v e r s io n
A /D
tA D C
c o n v e r s io n tim e
/3 2
A/D Conversion Timing
Low Voltage Reset - LVR
The relationship between VDD and VLVR is shown below.
The microcontroller provides low voltage reset circuit in
order to monitor the supply voltage of the device. If the
supply voltage of the device is within the range
0.9V~VLVR, such as changing a battery, the LVR will automatically reset the device internally.
V D D
5 .5 V
The LVR includes the following specifications:
3 .0 V
V
O P R
5 .5 V
V
· The low voltage (0.9V~VLVR) has to remain in their
2 .2 V
original state to exceed 1ms. If the low voltage state
does not exceed 1ms, the LVR will ignore it and do not
perform a reset function.
0 .9 V
· The LVR uses the ²OR² function with the external RES
Note: VOPR is the voltage range for proper chip
operation at 4MHz system clock.
signal to perform chip reset.
V
L V R
D D
5 .5 V
V
L V R
L V R
D e te c t V o lta g e
0 .9 V
0 V
R e s e t S ig n a l
N o r m a l O p e r a tio n
R e s e t
*1
R e s e t
*2
Low Voltage Reset
Note:
*1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of 1024 system
clock pulses before entering the normal operation.
*2: Since low voltage state has to be maintained in its original state for over 1ms, therefore after 1ms delay,
the device enters the reset mode.
Rev. 1.00
24
April 23, 2008
HT46RU232
I2C Bus Serial Interface
vice is working in transmit or receive mode. When SRW
bit is set ²1², it means that the master wants to read data
from I2C Bus, the slave device must write data to I2C
Bus, so the slave device is working in transmit mode.
When SRW is reset to ²0², it means that the master
wants to write data to I2C Bus, the slave device must
read data from the bus, so the slave device is working in
receive mode. The RXAK bit is reset ²0² indicates an acknowledges signal has been received. In the transmit
mode, the transmitter checks RXAK bit to know the receiver which wants to receive the next data byte, so the
transmitter continue to write data to the I2C Bus until the
RXAK bit is set to ²1² and the transmitter releases the
SDA line, so that the master can send the STOP signal
to release the bus.
I2C Bus is implemented in the device. The I2C Bus is a
bidirectional two-wire lines. The data line and clock line
are implement in SDA pin and SCL pin. The SDA and
SCL are NMOS open drain output pin. They must connect a pull-high resistor respectively.
Using the I2C Bus, the device has two ways to transfer
data. One is in slave transmit mode, the other is in slave
receive mode. There are four registers related to I2C
Bus; HADR([20H]), HCR([21H]), HSR([22H]),
HDR([23H]). The HADR register is the slave address
setting of the device, if the master sends the calling address which match, it means that this device is selected.
The HCR is I2C Bus control register which defines the
device enable or disable the I2C Bus as a transmitter or
as a receiver. The HSR is I2C Bus status register, it responds with the I2C Bus status. The HDR is input/output
data register, data to transmit or receive must be via the
HDR register.
The HADR bit7-bit1 define the device slave address. At
the beginning of transfer, the master must select a device by sending the address of the slave device. The bit
0 is unused and is not defined. If the I2C Bus receives a
start signal, all slave device notice the continuity of the
8-bit data. The front of 7 bits is slave address and the
first bit is MSB. If the address is match, the HAAS status
bit is set and generate an I2C Bus interrupt. In the ISR,
the slave device must check the HAAS bit to know the
I2C Bus interrupt comes from the slave address that has
match or completed one 8-bit data transfer. The last bit
of the 8-bit data is read/write command bit, it responds in
SRW bit. The slave will check the SRW bit to know if the
master wants to transmit or receive data. The device
check SRW bit to know it is as a transmitter or receiver.
The I2C Bus control register contains three bits. The
HEN bit defines whether to enable or disable the I2C
Bus. If the data wants to transfer via I2C Bus, this bit
must be set. The HTX bit defines whether the I2C Bus is
in transmit or receive mode. If the device is as a transmitter, this bit must be set to ²1². The TXAK defines the
transmit acknowledge signal, when the device received
8-bit data, the device sends this bit to I2C Bus at the 9th
clock. If the receiver wants to continue to receive the
next data, this bit must be reset to ²0² before receiving
data.
The I2C Bus status register contains 5 bits. The HCF bit
is reset to ²0² when one data byte is being transferred. If
one data transfer is completed, this bit is set to ²1². The
HAAS bit is set ²1² when the address is match, and the
I2C Bus interrupt request flag is set to ²1². If the interrupt
is enabled and the stack is not full, a subroutine call to
location 10H will occur. Writing data to the I2C Bus control register clears HAAS bit. If the address is not match,
this bit is reset to ²0². The HBB bit is set to respond the
I2C Bus is busy. It mean that a START signal is detected.
This bit is reset to ²0² when the I2C Bus is not busy. It
means that a STOP signal is detected and the I2C Bus is
free. The SRW bit defines the read/write command bit, if
the calling address is match. When HAAS is set to ²1²,
the device check SRW bit to determine whether the de-
Rev. 1.00
Bit7~Bit1
Bit0
Slave Address
¾
²¾² means undefined
HADR (20H) Register
The HDR register is the I2C Bus input/output data register. Before transmitting data, the HDR must write the
data which needs to be transmitted. Before receiving
data, the device must dummy read data from HDR.
Transmit or Receive data from I2C Bus must be via the
HDR register.
At the beginning of the transfer of the I2C Bus, the device must initial the bus, the following are the notes for
initialing the I2C Bus:
25
April 23, 2008
HT46RU232
S ta rt
W r ite S la v e
A d d re s s to H A D R
S E T H E N
D is a b le
I2C B u s
In te rru p t= ?
E n a b le
C L R E H I
P o ll H IF to d e c id e
w h e n to g o to I2C B u s IS R
S E T E H I
W a it fo r In te r r u p t
G o to M a in P r o g r a m
G o to M a in P r o g r a m
S ta rt
N o
N o
R e a d fro m
Y e s
Y e s
H T X = 1
?
H D R
R E T I
Y e s
Y e s
H A A S = 1
?
R X A K = 1
?
N o
C L R H T X
C L R T X A K
W r ite to H D R
D u m m y R e a d
fro m H D R
R E T I
S R W = 1
?
N o
S E T H T X
C L R H T X
C L R T X A K
W r ite to H D R
D u m m y R e a d
F ro m H D R
R E T I
R E T I
R E T I
Rev. 1.00
26
April 23, 2008
HT46RU232
Note:
1: Write the I2C Bus address register (HADR) to define its own slave address.
2: Set HEN bit of I2C Bus control register (HCR) bit 0 to enable the I2C Bus.
Bit No.
Label
0~2
¾
3
TXAK
4
HTX
5~6
¾
7
HEN
Function
Unused bit, read as ²0²
Enable/disable transmit acknowledge (0= acknowledge; 1= don¢t acknowledge)
Defines the transmit/receive mode (0= receive mode; 1= transmit)
Unused bit, read as ²0²
Enable/disable I2C Bus function (0= disable; 1= enable)
HCR (21H) Register
3: Set EHI bit of the interrupt control register 1 (INTC1) bit 0 to enable the I2C Bus interrupt.
Bit No.
Label
Function
0
RXAK
RXAK is cleared to ²0² when the master receives an 8-bit data and acknowledgment
at the 9th clock, RXAK is set to ²1² means not acknowledged.
1
¾
2
SRW
3~4
¾
5
HBB
HBB is set to ²1² when I2C Bus is busy and HBB is cleared to ²0² means that the I2C
Bus is not busy.
6
HAAS
HAAS is set to ²1² when the calling address has matched, and I2C Bus interrupt will
occur and HCF is set.
7
HCF
HCF is cleared to ²0² when one data byte is being transferred, HCF is set to ²1² indicating 8-bit data communication has been finished.
Unused bit, read as ²0²
SRW is set to ²1² when the master wants to read data from the I2C Bus, so the slave
must transmit data to the master. SRW is cleared to ²0² when the master wants to
write data to the I2C Bus, so the slave must receive data from the master.
Unused bit, read as ²0²
HSR (22H) Register
S C L
S ta rt
S R W
S la v e A d d r e s s
0
1
S D A
1
1
0
1
0
1
D a ta
S C L
1
0
0
1
A C K
0
A C K
0
1
0
S to p
0
S D A
S = S
S A =
S R =
M = S
D = D
A = A
P = S
S
ta rt (1
S la v e
S R W
la v e d
a ta (8
C K (R
to p (1
S A
b it)
A d d r e s s ( 7 b its )
b it ( 1 b it)
e v ic e s e n d a c k n o w le d g e b it ( 1 b it)
b its )
X A K b it fo r tr a n s m itte r , T X A K b it fo r r e c e iv e r 1 b it)
b it)
S R
M
D
A
D
A
S
S A
S R
M
D
A
D
A
P
I2C Communication Timing Diagram
Rev. 1.00
27
April 23, 2008
HT46RU232
Start Signal
Acknowledge Bit
The START signal is generated only by the master device. The other device in the bus must detect the START
signal to set the I2C Bus busy bit (HBB). The START signal is SDA line from high to low, when SCL is high.
One of the slave device generates an acknowledge signal,
when the slave address is matched. The master device
can check this acknowledge bit to know if the slave device
accepts the calling address. If no acknowledge bit, the
master must send a STOP bit and end the communication.
When the I2C Bus status register bit 6 HAAS is high, it
means the address is matched, so the slave must check
SRW as a transmitter (set HTX) to ²1² or as a receiver
(clear HTX) to ²0².
S C L
S D A
Start Bit
S C L
Slave Address
S D A
The master must select a device for transferring the
data by sending the slave device address after the
START signal. All device in the I2C Bus will receive the
I2C Bus slave address (7 bits) to compare with its own
slave address (7 bits). If the slave address is matched,
the slave device will generate an interrupt and save the
following bit (8th bit) to SRW bit and sends an acknowledge bit (low level) to the 9th bit. The slave device also
sets the status flag (HAAS), when the slave address is
matched.
Stop Bit
Data Byte
The data is 8 bits and is sent after the slave device has
acknowledged the slave address. The first bit is MSB
and the 8th bit is LSB. The receiver sends the acknowledge signal (²0²) and continues to receive the next one
byte data. If the transmitter checks and there¢s no acknowledge signal, then it release the SDA line, and the
master sends a STOP signal to release the I2C Bus. The
data is stored in the HDR register. The transmitter must
write data to the HDR before transmitting data and the
receiver must read data from the HDR after receiving
data.
In interrupt subroutine, check HAAS bit to know whether
the I2C Bus interrupt comes from a slave address that is
matched or a data byte transfer is completed. When the
slave address is matched, the device must be in transmit mode or receive mode and write data to HDR or
dummy read from HDR to release the SCL line.
S C L
SRW Bit
The SRW bit means that the master device wants to
read from or write to the I2C Bus. The slave device
check this bit to understand itself if it is a transmitter or a
receiver. The SRW bit is set to ²1² means that the master wants to read data from the I2C Bus, so the slave device must write data to a bus as a transmitter. The SRW
is cleared to ²0² means that the master wants to write
data to the I2C Bus, so the slave device must read data
from the I2C Bus as a receiver.
Rev. 1.00
S D A
S ta r t b it
S to p b it
D a ta
s ta b le
D a ta
a llo w
c h a n g e
Data Timing Diagram
Receive Acknowledge Bit
When the receiver wants to continue to receive the next
data byte, it generates an acknowledge bit (TXAK) at
the 9th clock. The transmitter checks the acknowledge
bit (RXAK) to continue to write data to the I2C Bus or
change to receive mode and dummy read the HDR register to release the SDA line and the master sends the
STOP signal.
28
April 23, 2008
HT46RU232
zero. Similarly, the RX pin is the UART receiver pin,
which can also be used as a general purpose I/O pin,
if the pin is not configured as a receiver, which occurs
if the RXEN bit in the UCR2 register is equal to zero.
Along with the UARTEN bit, the TXEN and RXEN bits,
if set, will automatically setup these I/O pins to their respective TX output and RX input conditions and disable any pull-high resistor option which may exist on
the RX pin.
UART Bus Serial Interface
The HT46RU232 devices contain an integrated full-duplex asynchronous serial communications UART interface that enables communication with external devices
that contain a serial interface. The UART function has
many features and can transmit and receive data serially by transferring a frame of data with eight or nine
data bits per transmission as well as being able to detect
errors when the data is overwritten or incorrectly
framed. The UART function possesses its own internal
interrupt which can be used to indicate when a reception
occurs or when a transmission terminates.
· UART data transfer scheme
The block diagram shows the overall data transfer
structure arrangement for the UART. The actual data
to be transmitted from the MCU is first transferred to
the TXR register by the application program. The data
will then be transferred to the Transmit Shift Register
from where it will be shifted out, LSB first, onto the TX
pin at a rate controlled by the Baud Rate Generator.
Only the TXR register is mapped onto the MCU Data
Memory, the Transmit Shift Register is not mapped
and is therefore inaccessible to the application program.
Data to be received by the UART is accepted on the
external RX pin, from where it is shifted in, LSB first, to
the Receiver Shift Register at a rate controlled by the
Baud Rate Generator. When the shift register is full,
the data will then be transferred from the shift register
to the internal RXR register, where it is buffered and
can be manipulated by the application program. Only
the RXR register is mapped onto the MCU Data Memory, the Receiver Shift Register is not mapped and is
therefore inaccessible to the application program.
It should be noted that the actual register for data
transmission and reception, although referred to in the
text, and in application programs, as separate TXR
and RXR registers, only exists as a single shared register in the Data Memory. This shared register known
as the TXR/RXR register is used for both data transmission and data reception.
· UART features
The integrated UART function contains the following
features:
¨
Full-duplex, asynchronous communication
¨
8 or 9 bits character length
¨
Even, odd or no parity options
¨
One or two stop bits
¨
Baud rate generator with 8-bit prescaler
¨
Parity, framing, noise and overrun error detection
¨
Support for interrupt on address detect
(last character bit=1)
¨
Separately enabled transmitter and receiver
¨
2-byte Deep Fifo Receive Data Buffer
¨
Transmit and receive interrupts
¨
Interrupts can be initialized by the following
conditions:
-
Transmitter Empty
-
Transmitter Idle
-
Receiver Full
-
Receiver Overrun
-
Address Mode Detect
· UART status and control registers
· UART external pin interfacing
There are five control registers associated with the
UART function. The USR, UCR1 and UCR2 registers
control the overall function of the UART, while the
BRG register controls the Baud rate. The actual data
to be transmitted and received on the serial interface
is managed through the TXR/RXR data registers.
To communicate with an external serial interface, the
internal UART has two external pins known as TX and
RX. The TX pin is the UART transmitter pin, which can
be used as a general purpose I/O pin if the pin is not
configured as a UART transmitter, which occurs when
the TXEN bit in the UCR2 control register is equal to
T r a n s m itte r S h ift R e g is te r
M S B
R e c e iv e r S h ift R e g is te r
L S B
T X P in
C L K
T X R
R e g is te r
M S B
R X P in
L S B
C L K
B a u d R a te
G e n e ra to r
M C U
R X R
R e g is te r
B u ffe r
D a ta B u s
UART Data Transfer Scheme
Rev. 1.00
29
April 23, 2008
HT46RU232
· USR register
RXIF flag is cleared when the USR register is read
with RXIF set, followed by a read from the RXR register, and if the RXR register has no data available.
The USR register is the status register for the UART,
which can be read by the program to determine the
present status of the UART. All flags within the USR
register are read only.
Further explanation on each of the flags is given below:
¨
¨
¨
TXIF
The TXIF flag is the transmit data register empty
flag. When this read only flag is ²0² it indicates that
the character is not transferred to the transmit shift
registers. When the flag is ²1² it indicates that the
transmit shift register has received a character from
the TXR data register. The TXIF flag is cleared by
reading the UART status register (USR) with TXIF
set and then writing to the TXR data register. Note
that when the TXEN bit is set, the TXIF flag bit will
also be set since the transmit buffer is not yet full.
TIDLE
The TIDLE flag is known as the transmission complete flag. When this read only flag is ²0² it indicates
that a transmission is in progress. This flag will be
set to ²1² when the TXIF flag is ²1² and when there
is no transmit data, or break character being transmitted. When TIDLE is ²1² the TX pin becomes idle.
The TIDLE flag is cleared by reading the USR register with TIDLE set and then writing to the TXR register. The flag is not generated when a data character,
or a break is queued and ready to be sent.
RXIF
The RXIF flag is the receive register status flag.
When this read only flag is ²0² it indicates that the
RXR read data register is empty. When the flag is
²1² it indicates that the RXR read data register contains new data. When the contents of the shift register are transferred to the RXR register, an interrupt
is generated if RIE=1 in the UCR2 register. If one or
more errors are detected in the received word, the
appropriate receive-related flags NF, FERR, and/or
PERR are set within the same clock cycle. The
b 7
P E R R
¨
RIDLE
The RIDLE flag is the receiver status flag. When
this read only flag is ²0² it indicates that the receiver
is between the initial detection of the start bit and
the completion of the stop bit. When the flag is ²1² it
indicates that the receiver is idle. Between the completion of the stop bit and the detection of the next
start bit, the RIDLE bit is ²1² indicating that the
UART is idle.
¨
OERR
The OERR flag is the overrun error flag, which indicates when the receiver buffer has overflowed.
When this read only flag is ²0² there is no overrun error. When the flag is ²1² an overrun error occurs
which will inhibit further transfers to the RXR receive
data register. The flag is cleared by a software sequence, which is a read to the status register USR
followed by an access to the RXR data register.
¨
FERR
The FERR flag is the framing error flag. When this
read only flag is ²0² it indicates no framing error.
When the flag is ²1² it indicates that a framing error
has been detected for the current character. The
flag can also be cleared by a software sequence
which will involve a read to the USR status register
followed by an access to the RXR data register.
¨
NF
The NF flag is the noise flag. When this read only
flag is ²0² it indicates a no noise condition. When
the flag is ²1² it indicates that the UART has detected noise on the receiver input. The NF flag is set
during the same cycle as the RXIF flag but will not
be set in the case of an overrun. The NF flag can be
cleared by a software sequence which will involve a
read to the USR status register, followed by an access to the RXR data register.
b 0
N F
F E R R
O E R R
R ID L E
R X IF
T ID L E
T X IF
U S R
R e g is te r
T r a n s m it d a ta r e g is te r e m p ty
1 : c h a r a c te r tr a n s fe r r e d to tr a n s m it s h ift r e g is te r
0 : c h a r a c te r n o t tr a n s fe r r e d to tr a n s m it s h ift r e g is te r
T r a n s m is s io n id le
1 : n o tr a n s m is s io n in p r o g r e s s
0 : tr a n s m is s io n in p r o g r e s s
R e c e iv e R X R r e g is te r s ta tu s
1 : R X R r e g is te r h a s a v a ila b le d a ta
0 : R X R r e g is te r is e m p ty
R e c e iv e r s ta tu s
1 : r e c e iv e r is id le
0 : d a ta b e in g r e c e iv e d
O v e rru n e rro r
1 : o v e rru n e rro r d e te c te d
0 : n o o v e rru n e rro r d e te c te d
F r a m in g e r r o r fla g
1 : fr a m in g e r r o r d e te c te d
0 : n o fr a m in g e r r o r
N o is e fla g
1 : n o is e d e te c te d
0 : n o n o is e d e te c te d
P a r ity e r r o r fla g
1 : p a r ity e r r o r d e te c te d
0 : n o p a r ity e r r o r d e te c te d
Rev. 1.00
30
April 23, 2008
HT46RU232
¨
used, if the bit is equal to ²0² then only one stop bit
is used.
PERR
The PERR flag is the parity error flag. When this
read only flag is ²0² it indicates that a parity error
has not been detected. When the flag is ²1² it indicates that the parity of the received word is incorrect. This error flag is applicable only if Parity mode
(odd or even) is selected. The flag can also be
cleared by a software sequence which involves a
read to the USR status register, followed by an access to the RXR data register.
· UCR1 register
The UCR1 register together with the UCR2 register
are the two UART control registers that are used to set
the various options for the UART function, such as
overall on/off control, parity control, data transfer bit
length etc.
Further explanation on each of the bits is given below:
¨
TX8
This bit is only used if 9-bit data transfers are used,
in which case this bit location will store the 9th bit of
the transmitted data, known as TX8. The BNO bit is
used to determine whether data transfers are in
8-bit or 9-bit format.
¨
RX8
This bit is only used if 9-bit data transfers are used,
in which case this bit location will store the 9th bit of
the received data, known as RX8. The BNO bit is
used to determine whether data transfers are in
8-bit or 9-bit format.
¨
TXBRK
The TXBRK bit is the Transmit Break Character bit.
When this bit is ²0² there are no break characters
and the TX pin operates normally. When the bit is
²1² there are transmit break characters and the
transmitter will send logic zeros. When equal to ²1²
after the buffered data has been transmitted, the
transmitter output is held low for a minimum of a
13-bit length and until the TXBRK bit is reset.
¨
STOPS
This bit determines if one or two stop bits are to be
used. When this bit is equal to ²1² two stop bits are
b 7
U A R T E N
¨
PRT
This is the parity type selection bit. When this bit is
equal to ²1² odd parity will be selected, if the bit is
equal to ²0² then even parity will be selected.
¨
PREN
This is parity enable bit. When this bit is equal to ²1²
the parity function will be enabled, if the bit is equal
to ²0² then the parity function will be disabled.
¨
BNO
This bit is used to select the data length format,
which can have a choice of either 8-bits or 9-bits. If
this bit is equal to ²1² then a 9-bit data length will be
selected, if the bit is equal to ²0² then an 8-bit data
length will be selected. If 9-bit data length is selected then bits RX8 and TX8 will be used to store
the 9th bit of the received and transmitted data respectively.
¨
UARTEN
The UARTEN bit is the UART enable bit. When the
bit is ²0² the UART will be disabled and the RX and
TX pins will function as General Purpose I/O pins.
When the bit is ²1² the UART will be enabled and
the TX and RX pins will function as defined by the
TXEN and RXEN control bits. When the UART is
disabled it will empty the buffer so any character remaining in the buffer will be discarded. In addition,
the baud rate counter value will be reset. When the
UART is disabled, all error and status flags will be
reset. The TXEN, RXEN, TXBRK, RXIF, OERR,
FERR, PERR, and NF bits will be cleared, while the
TIDLE, TXIF and RIDLE bits will be set. Other control bits in UCR1, UCR2, and BRG registers will remain unaffected. If the UART is active and the
UARTEN bit is cleared, all pending transmissions
and receptions will be terminated and the module
will be reset as defined above. When the UART is
re-enabled it will restart in the same configuration.
b 0
B N O
P R E N
P R T
S T O P S
T X B R K
R X 8
T X 8
U C R 1 R e g is te r
T r a n s m it d a ta b it 8 ( w r ite o n ly )
R e c e iv e d a ta b it 8 ( r e a d o n ly )
T r a n s m it b r e a k c h a r a c te r
1 : tr a n s m it b r e a k c h a r a c te r s
0 : n o b re a k c h a ra c te rs
D e fin e s th e n u m b e r o f s to p b its
1 : tw o s to p b its
0 : o n e s to p b it
P a r ity ty p e b it
1 : o d d p a r ity fo r p a r ity g e n e r a to r
0 : e v e n p a r ity fo r p a r ity g e n e r a to r
P a r ity e n a b le b it
1 : p a r ity fu n c tio n e n a b le d
0 : p a r ity fu n c tio n d is a b le d
N u m b e r o f d a ta tr a n s fe r b its
1 : 9 - b it d a ta tr a n s fe r
0 : 8 - b it d a ta tr a n s fe r
U A R T e n a b le b it
1 : e n a b le U A R T , T X & R X p in s a s U A R T p in s
0 : d is a b le U A R T , T X & R X p in s a s I/O p o r t p in s
Rev. 1.00
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April 23, 2008
HT46RU232
· UCR2 register
to ²0² and if the MCU is in the Power Down Mode,
any edge transitions on the RX pin will not wake-up
the device.
The UCR2 register is the second of the two UART
control registers and serves several purposes. One of
its main functions is to control the basic enable/disable operation of the UART Transmitter and Receiver
as well as enabling the various UART interrupt
sources. The register also serves to control the baud
rate speed, receiver wake-up enable and the address
detect enable.
Further explanation on each of the bits is given below:
¨
ADDEN
The ADDEN bit is the address detect mode bit.
When this bit is ²1² the address detect mode is enabled. When this occurs, if the 8th bit, which corresponds to RX7 if BNO=0, or the 9th bit, which
corresponds to RX8 if BNO=1, has a value of ²1²
then the received word will be identified as an address, rather than data. If the corresponding interrupt is enabled, an interrupt request will be
generated each time the received word has the address bit set, which is the 8 or 9 bit depending on the
value of BNO. If the address bit is ²0² an interrupt
will not be generated, and the received data will be
discarded.
¨
TEIE
This bit enables or disables the transmitter empty
interrupt. If this bit is equal to ²1² when the transmitter empty TXIF flag is set, due to a transmitter
empty condition, the UART interrupt request flag
will be set. If this bit is equal to ²0² the UART interrupt request flag will not be influenced by the condition of the TXIF flag.
¨
¨
TIIE
This bit enables or disables the transmitter idle interrupt. If this bit is equal to ²1² when the transmitter
idle TIDLE flag is set, the UART interrupt request
flag will be set. If this bit is equal to ²0² the UART interrupt request flag will not be influenced by the
condition of the TIDLE flag.
BRGH
The BRGH bit selects the high or low speed mode
of the Baud Rate Generator. This bit, together with
the value placed in the BRG register, controls the
Baud Rate of the UART. If this bit is equal to ²1² the
high speed mode is selected. If the bit is equal to ²0²
the low speed mode is selected.
¨
¨
RIE
This bit enables or disables the receiver interrupt. If
this bit is equal to ²1² when the receiver overrun
OERR flag or receive data available RXIF flag is
set, the UART interrupt request flag will be set. If
this bit is equal to ²0² the UART interrupt will not be
influenced by the condition of the OERR or RXIF
flags.
¨
WAKE
This bit enables or disables the receiver wake-up
function. If this bit is equal to ²1² and if the MCU is in
the Power Down Mode, a low going edge on the RX
input pin will wake-up the device. If this bit is equal
RXEN
The RXEN bit is the Receiver Enable Bit. When this
bit is equal to ²0² the receiver will be disabled with
any pending data receptions being aborted. In addition the buffer will be reset. In this situation the RX
pin can be used as a general purpose I/O pin. If the
RXEN bit is equal to ²1² the receiver will be enabled
and if the UARTEN bit is equal to ²1² the RX pin will
be controlled by the UART. Clearing the RXEN bit
during a transmission will cause the data reception
to be aborted and will reset the receiver. If this occurs, the RX pin can be used as a general purpose
I/O pin.
b 7
T X E N
b 0
R X E N
B R G H
A D D E N
W A K E
R IE
T IIE
T E IE
U C R 2 R e g is te r
T r a n s m itte r e m p ty in te r r u p t e n a b le
1 : T X IF in te r r u p t r e q u e s t e n a b le
0 : T X IF in te r r u p t r e q u e s t d is a b le
T r a n s m itte r id le in te r r u p t e n a b le
1 : T ID L E in te r r u p t r e q u e s t e n a b le
0 : T ID L E in te r r u p t r e q u e s t d is a b le
R e c e iv e r in te r r u p t e n a b le
1 : R X IF in te r r u p t r e q u e s t e n a b le
0 : R X IF in te r r u p t r e q u e s t d is a b le
D e fin e s th e R X w a k e u p e n a b le
1 : R X w a k e u p e n a b le ( fa llin g e d g e )
0 : R X w a k e u p d is a b le
A d d re s s d e te c t m o d e
1 : e n a b le
0 : d is a b le
H ig h b a u d r a te s e le c t b it
1 : h ig h s p e e d
0 : lo w s p e e d
R e c e iv e r e n a b le b it
1 : r e c e iv e r e n a b le
0 : r e c e iv e r d is a b le
T r a n s m itte r e n a b le b it
1 : tr a n s m itte r e n a b le
0 : tr a n s m itte r d is a b le
Rev. 1.00
32
April 23, 2008
HT46RU232
¨
TXEN
The TXEN bit is the Transmitter Enable Bit. When
this bit is equal to ²0² the transmitter will be disabled
with any pending transmissions being aborted. In
addition the buffer will be reset. In this situation the
TX pin can be used as a general purpose I/O pin. If
the TXEN bit is equal to ²1² the transmitter will be
enabled and if the UARTEN bit is equal to ²1² the
TX pin will be controlled by the UART. Clearing the
TXEN bit during a transmission will cause the transmission to be aborted and will reset the transmitter.
If this occurs, the TX pin can be used as a general
purpose I/O pin.
By programming the BRGH bit which allows selection
of the related formula and programming the required
value in the BRG register, the required baud rate can
be setup. Note that because the actual baud rate is
determined using a discrete value, N, placed in the
BRG register, there will be an error associated between the actual and requested value. The following
example shows how the BRG register value N and the
error value can be calculated.
Calculating the register and error values
For a clock frequency of 8MHz, and with BRGH set to
²0² determine the BRG register value N, the actual
baud rate and the error value for a desired baud rate
of 9600.
From the above table the desired baud rate BR
fSYS
=
[64 (N+1)]
fSYS
Re-arranging this equation gives N =
-1
(BRx64)
8000000
- 1 = 12.0208
Giving a value for N =
(9600x 64)
· Baud rate generator
To setup the speed of the serial data communication,
the UART function contains its own dedicated baud
rate generator. The baud rate is controlled by its own
internal free running 8-bit timer, the period of which is
determined by two factors. The first of these is the
value placed in the BRG register and the second is the
value of the BRGH bit within the UCR2 control register. The BRGH bit decides, if the baud rate generator
is to be used in a high speed mode or low speed
mode, which in turn determines the formula that is
used to calculate the baud rate. The value in the BRG
register determines the division factor, N, which is
used in the following baud rate calculation formula.
Note that N is the decimal value placed in the BRG
register and has a range of between 0 and 255.
UCR2 BRGH Bit
Baud Rate
0
1
fSYS
[64 (N+1)]
fSYS
[16 (N+1)]
To obtain the closest value, a decimal value of 12
should be placed into the BRG register. This gives an
actual or calculated baud rate value of
8000000
BR =
= 9615
[64(12+1)]
Therefore the error is equal to = 0.16%
The following tables show actual values of baud rate and error values for the two values of BRGH.
Baud
Rate
K/BPS
Baud Rates for BRGH=0
fSYS=8MHz
fSYS=7.159MHz
fSYS=4MHz
fSYS=3.579545MHz
BRG
Kbaud
Error
BRG
Kbaud
Error
BRG
Kbaud
Error
BRG
Kbaud
Error
0.3
¾
¾
¾
¾
¾
¾
207
0.300
0.00
185
0.300
0.00
1.2
103
1.202
0.16
92
1.203
0.23
51
1.202
0.16
46
1.19
-0.83
2.4
51
2.404
0.16
46
2.38
-0.83
25
2.404
0.16
22
2.432
1.32
4.8
25
4.807
0.16
22
4.863
1.32
12
4.808
0.16
11
4.661
-2.9
9.6
12
9.615
0.16
11
9.322
-2.9
6
8.929
-6.99
5
9.321
-2.9
19.2
6
17.857
-6.99
5
18.64
-2.9
2
20.83
8.51
2
18.643
-2.9
38.4
2
41.667
8.51
2
37.29
-2.9
1
¾
¾
1
¾
¾
57.6
1
62.5
8.51
1
55.93
-2.9
0
62.5
8.51
0
55.93
-2.9
115.2
0
125
8.51
0
111.86
-2.9
¾
¾
¾
¾
¾
¾
Baud Rates and Error Values for BRGH = 0
Rev. 1.00
33
April 23, 2008
HT46RU232
Baud
Rate
K/BPS
Baud Rates for BRGH=1
fSYS=8MHz
fSYS=7.159MHz
fSYS=4MHz
fSYS=3.579545MHz
BRG
Kbaud
Error
BRG
Kbaud
Error
BRG
Kbaud
Error
BRG
Kbaud
Error
0.3
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
1.2
¾
¾
¾
¾
¾
¾
207
1.202
0.16
185
1.203
0.23
2.4
207
2.404
0.16
185
2.405
0.23
103
2.404
0.16
92
2.406
0.23
4.8
103
4.808
0.16
92
4.811
0.23
51
4.808
0.16
46
4.76
-0.83
9.6
51
9.615
0.16
46
9.520
-0.832
25
9.615
0.16
22
9.727
1.32
19.2
25
19.231
0.16
22
19.454
1.32
12
19.231
0.16
11
18.643
-2.9
38.4
12
38.462
0.16
11
37.287
-2.9
6
35.714
-6.99
5
37.286
-2.9
57.6
8
55.556
-3.55
7
55.93
-2.9
3
62.5
8.51
3
55.930
-2.9
115.2
3
125
8.51
3
111.86
-2.9
1
125
8.51
1
111.86
-2.9
250
1
250
0
¾
¾
¾
0
250
0
¾
¾
¾
Baud Rates and Error Values for BRGH = 1
· Setting up and controlling the UART
¨
¨
Clearing the UARTEN bit will disable the TX and RX
pins and allow these two pins to be used as normal
I/O pins. When the UART function is disabled the
buffer will be reset to an empty condition, at the
same time discarding any remaining residual data.
Disabling the UART will also reset the error and status flags with bits TXEN, RXEN, TXBRK, RXIF,
OERR, FERR, PERR and NF being cleared while
bits TIDLE, TXIF and RIDLE will be set. The remaining control bits in the UCR1, UCR2 and BRG
registers will remain unaffected. If the UARTEN bit
in the UCR1 register is cleared while the UART is
active, then all pending transmissions and receptions will be immediately suspended and the UART
will be reset to a condition as defined above. If the
UART is then subsequently re-enabled, it will restart
again in the same configuration.
Introduction
For data transfer, the UART function utilizes a
non-return-to-zero, more commonly known as
NRZ, format. This is composed of one start bit, eight
or nine data bits, and one or two stop bits. Parity is
supported by the UART hardware, and can be
setup to be even, odd or no parity. For the most
common data format, 8 data bits along with no parity and one stop bit, denoted as 8, N, 1, is used as
the default setting, which is the setting at power-on.
The number of data bits and stop bits, along with the
parity, are setup by programming the corresponding
BNO, PRT, PREN, and STOPS bits in the UCR1
register. The baud rate used to transmit and receive
data is setup using the internal 8-bit baud rate generator, while the data is transmitted and received
LSB first. Although the UART¢s transmitter and receiver are functionally independent, they both use
the same data format and baud rate. In all cases
stop bits will be used for data transmission.
¨
Enabling/disabling the UART
The basic on/off function of the internal UART function is controlled using the UARTEN bit in the UCR1
register. As the UART transmit and receive pins, TX
and RX respectively, are pin-shared with normal I/O
pins, one of the basic functions of the UARTEN control bit is to control the UART function of these two
pins. If the UARTEN, TXEN and RXEN bits are set,
then these two I/O pins will be setup as a TX output
pin and an RX input pin respectively, in effect disabling the normal I/O pin function. If no data is being
transmitted on the TX pin then it will default to a
logic high value.
Rev. 1.00
34
Data, parity and stop bit selection
The format of the data to be transferred, is composed of various factors such as data bit length,
parity on/off, parity type, address bits and the number of stop bits. These factors are determined by
the setup of various bits within the UCR1 register.
The BNO bit controls the number of data bits which
can be set to either 8 or 9, the PRT bit controls the
choice of odd or even parity, the PREN bit controls
the parity on/off function and the STOPS bit decides
whether one or two stop bits are to be used. The following table shows various formats for data transmission. The address bit identifies the frame as an
address character. The number of stop bits, which
can be either one or two, is independent of the data
length.
April 23, 2008
HT46RU232
Start
Bit
Data
Bits
Address
Bits
Parity
Bits
Stop
Bit
¨
Example of 8-bit Data Formats
1
8
0
0
1
1
7
0
1
1
7
1
0
1
1
1
Example of 9-bit Data Formats
1
9
0
0
1
1
8
0
1
1
1
8
11
0
1
Transmitting data
When the UART is transmitting data, the data is
shifted on the TX pin from the shift register, with the
least significant bit first. In the transmit mode, the
TXR register forms a buffer between the internal
bus and the transmitter shift register. It should be
noted that if 9-bit data format has been selected,
then the MSB will be taken from the TX8 bit in the
UCR1 register. The steps to initiate a data transfer
can be summarized as follows:
-
Make the correct selection of the BNO, PRT,
PREN and STOPS bits to define the required
word length, parity type and number of stop bits.
-
Setup the BRG register to select the desired baud
rate.
-
Set the TXEN bit to ensure that the TX pin is used
as a UART transmitter pin and not as an I/O pin.
-
Access the USR register and write the data that is
to be transmitted into the TXR register. Note that
this step will clear the TXIF bit.
-
This sequence of events can now be repeated to
send additional data.
Transmitter Receiver Data Format
The following diagram shows the transmit and receive
waveforms for both 8-bit and 9-bit data formats.
· UART transmitter
Data word lengths of either 8 or 9 bits, can be selected
by programming the BNO bit in the UCR1 register.
When BNO bit is set, the word length will be set to 9
bits. In this case the 9th bit, which is the MSB, needs
to be stored in the TX8 bit in the UCR1 register. At the
transmitter core lies the Transmitter Shift Register,
more commonly known as the TSR, whose data is obtained from the transmit data register, which is known
as the TXR register. The data to be transmitted is
loaded into this TXR register by the application program. The TSR register is not written to with new data
until the stop bit from the previous transmission has
been sent out. As soon as this stop bit has been transmitted, the TSR can then be loaded with new data
from the TXR register, if it is available. It should be
noted that the TSR register, unlike many other registers, is not directly mapped into the Data Memory area
and as such is not available to the application program
for direct read/write operations. An actual transmission of data will normally be enabled when the TXEN
bit is set, but the data will not be transmitted until the
TXR register has been loaded with data and the baud
rate generator has defined a shift clock source. However, the transmission can also be initiated by first
loading data into the TXR register, after which the
TXEN bit can be set. When a transmission of data begins, the TSR is normally empty, in which case a
transfer to the TXR register will result in an immediate
transfer to the TSR. If during a transmission the TXEN
bit is cleared, the transmission will immediately cease
and the transmitter will be reset. The TX output pin will
then return to having a normal general purpose I/O pin
function.
It should be noted that when TXIF=0, data will be inhibited from being written to the TXR register. Clearing the TXIF flag is always achieved using the
following software sequence:
1. A USR register access
2. A TXR register write execution
The read-only TXIF flag is set by the UART hardware and if set indicates that the TXR register is
empty and that other data can now be written into
the TXR register without overwriting the previous
data. If the TEIE bit is set then the TXIF flag will generate an interrupt.
During a data transmission, a write instruction to the
TXR register will place the data into the TXR register, which will be copied to the shift register at the
end of the present transmission. When there is no
data transmission in progress, a write instruction to
the TXR register will place the data directly into the
shift register, resulting in the commencement of
data transmission, and the TXIF bit being immediately set. When a frame transmission is complete,
which happens after stop bits are sent or after the
break frame, the TIDLE bit will be set. To clear the
TIDLE bit the following software sequence is used:
1. A USR register access
2. A TXR register write execution
Note that both the TXIF and TIDLE bits are cleared
by the same software sequence.
P a r ity B it
S ta r t B it
B it 0
B it 1
B it 2
B it 3
B it 4
B it 5
B it 6
B it 7
S to p B it
N e x t
S ta rt
B it
8 -B it D a ta F o r m a t
P a r ity B it
S ta r t B it
B it 0
B it 1
B it 2
B it 3
B it 4
B it 5
B it 6
B it 7
B it 8
S to p B it
N e x t
S ta rt
B it
9 -B it D a ta F o r m a t
Rev. 1.00
35
April 23, 2008
HT46RU232
¨
-
Transmit break
If the TXBRK bit is set then break characters will be
sent on the next transmission. Break character
transmission consists of a start bit, followed by 13´
N ¢0¢ bits and stop bits, where N=1, 2, etc. If a break
character is to be transmitted then the TXBRK bit
must be first set by the application program, then
cleared to generate the stop bits. Transmitting a
break character will not generate a transmit interrupt. Note that a break condition length is at least 13
bits long. If the TXBRK bit is continually kept at a
logic high level then the transmitter circuitry will
transmit continuous break characters. After the application program has cleared the TXBRK bit, the
transmitter will finish transmitting the last break
character and subsequently send out one or two
stop bits. The automatic logic highs at the end of the
last break character will ensure that the start bit of
the next frame is recognized.
At this point the receiver will be enabled which will
begin to look for a start bit.
When a character is received the following sequence of events will occur:
Introduction
The UART is capable of receiving word lengths of either 8 or 9 bits. If the BNO bit is set, the word length
will be set to 9 bits with the MSB being stored in the
RX8 bit of the UCR1 register. At the receiver core lies
the Receive Serial Shift Register, commonly known
as the RSR. The data which is received on the RX
external input pin, is sent to the data recovery block.
The data recovery block operating speed is 16 times
that of the baud rate, while the main receive serial
shifter operates at the baud rate. After the RX pin is
sampled for the stop bit, the received data in RSR is
transferred to the receive data register, if the register
is empty. The data which is received on the external
RX input pin is sampled three times by a majority detect circuit to determine the logic level that has been
placed onto the RX pin. It should be noted that the
RSR register, unlike many other registers, is not directly mapped into the Data Memory area and as
such is not available to the application program for
direct read/write operations.
¨
Receiving data
When the UART receiver is receiving data, the data
is serially shifted in on the external RX input pin,
LSB first. In the read mode, the RXR register forms
a buffer between the internal bus and the receiver
shift register. The RXR register is a two byte deep
FIFO data buffer, where two bytes can be held in the
FIFO while a third byte can continue to be received.
Note that the application program must ensure that
the data is read from RXR before the third byte has
been completely shifted in, otherwise this third byte
will be discarded and an overrun error OERR will be
subsequently indicated. The steps to initiate a data
transfer can be summarized as follows:
-
Make the correct selection of BNO, PRT, PREN
and STOPS bits to define the word length, parity
type and number of stop bits.
-
Setup the BRG register to select the desired baud
rate.
Rev. 1.00
-
The RXIF bit in the USR register will be set when
RXR register has data available, at least one
more character can be read.
-
When the contents of the shift register have been
transferred to the RXR register, then if the RIE bit
is set, an interrupt will be generated.
-
If during reception, a frame error, noise error, parity error, or an overrun error has been detected,
then the error flags can be set.
The RXIF bit can be cleared using the following
software sequence:
1. A USR register access
2. An RXR register read execution
· UART receiver
¨
Set the RXEN bit to ensure that the RX pin is used
as a UART receiver pin and not as an I/O pin.
¨
¨
36
Receive break
Any break character received by the UART will be
managed as a framing error. The receiver will count
and expect a certain number of bit times as specified by the values programmed into the BNO and
STOPS bits. If the break is much longer than 13 bit
times, the reception will be considered as complete
after the number of bit times specified by BNO and
STOPS. The RXIF bit is set, FERR is set, zeros are
loaded into the receive data register, interrupts are
generated if appropriate and the RIDLE bit is set. If
a long break signal has been detected and the receiver has received a start bit, the data bits and the
invalid stop bit, which sets the FERR flag, the receiver must wait for a valid stop bit before looking
for the next start bit. The receiver will not make the
assumption that the break condition on the line is
the next start bit. A break is regarded as a character
that contains only zeros with the FERR flag set. The
break character will be loaded into the buffer and no
further data will be received until stop bits are received. It should be noted that the RIDLE read only
flag will go high when the stop bits have not yet
been received. The reception of a break character
on the UART registers will result in the following:
-
The framing error flag, FERR, will be set.
-
The receive data register, RXR, will be cleared.
-
The OERR, NF, PERR, RIDLE or RXIF flags will
possibly be set.
Idle status
When the receiver is reading data, which means it
will be in between the detection of a start bit and the
reading of a stop bit, the receiver status flag in the
USR register, otherwise known as the RIDLE flag,
will have a zero value. In between the reception of a
stop bit and the detection of the next start bit, the
RIDLE flag will have a high value, which indicates
the receiver is in an idle condition.
April 23, 2008
HT46RU232
¨
-
Receiver interrupt
The read only receive interrupt flag RXIF in the USR
register is set by an edge generated by the receiver.
An interrupt is generated if RIE=1, when a word is
transferred from the Receive Shift Register, RSR, to
the Receive Data Register, RXR. An overrun error
can also generate an interrupt if RIE=1.
No interrupt will be generated. However this bit
rises at the same time as the RXIF bit which itself
generates an interrupt.
Note that the NF flag is reset by a USR register read
operation followed by an RXR register read
operation.
¨
Framing Error - FERR Flag
The read only framing error flag, FERR, in the USR
register, is set if a zero is detected instead of stop
bits. If two stop bits are selected, both stop bits must
be high, otherwise the FERR flag will be set. The
FERR flag is buffered along with the received data
and is cleared on any reset.
¨
Parity Error - PERR Flag
The read only parity error flag, PERR, in the USR
register, is set if the parity of the received word is incorrect. This error flag is only applicable if the parity
is enabled, PREN = 1, and if the parity type, odd or
even is selected. The read only PERR flag is buffered along with the received data bytes. It is
cleared on any reset. It should be noted that the
FERR and PERR flags are buffered along with the
corresponding word and should be read before
reading the data word.
· Managing receiver errors
Several types of reception errors can occur within the
UART module, the following section describes the
various types and how they are managed by the
UART.
¨
Overrun Error - OERR flag
The RXR register is composed of a two byte deep
FIFO data buffer, where two bytes can be held in the
FIFO register, while a third byte can continue to be
received. Before this third byte has been entirely
shifted in, the data should be read from the RXR
register. If this is not done, the overrun error flag
OERR will be consequently indicated.
In the event of an overrun error occurring, the following will happen:
-
The OERR flag in the USR register will be set.
-
The RXR contents will not be lost.
-
The shift register will be overwritten.
· UART interrupt scheme
The UART internal function possesses its own internal interrupt and independent interrupt vector. Several
individual UART conditions can generate an internal
UART interrupt. These conditions are, a transmitter
data register empty, transmitter idle, receiver data
available, receiver overrun, address detect and an RX
pin wake-up. When any of these conditions are created, if the UART interrupt is enabled and the stack is
not full, the program will jump to the UART interrupt
vector where it can be serviced before returning to the
main program. Four of these conditions, have a corresponding USR register flag, which will generate a
UART interrupt if its associated interrupt enable flag in
-
An interrupt will be generated if the RIE bit is set.
The OERR flag can be cleared by an access to the
USR register followed by a read to the RXR register.
¨
Noise Error - NF Flag
Over-sampling is used for data recovery to identify
valid incoming data and noise. If noise is detected
within a frame the following will occur:
-
The read only noise flag, NF, in the USR register
will be set on the rising edge of the RXIF bit.
-
Data will be transferred from the Shift register to
the RXR register.
U S R
R e g is te r
U C R 2 R e g is te r
0
T E IE
T r a n s m itte r E m p ty
F la g T X IF
1
IN T C 1
R e g is te r
U A R T In te rru p t
R e q u e s t F la g
U R F
0
T IIE
T r a n s m itte r Id le
F la g T ID L E
1
R e c e iv e r O v e r r u n
F la g O E R R
R e c e iv e r D a ta
A v a ila b le R X IF
E M I
0
R IE
O R
E U R I
IN T C 0
R e g is te r
1
0
A D D E N
1
0
1
R X P in
W a k e -u p
0
W A K E
R X 7 if B N O = 0
R X 8 if B N O = 1
1
U C R 2 R e g is te r
UART Interrupt Scheme
Rev. 1.00
37
April 23, 2008
HT46RU232
the UCR2 register is set. The two transmitter interrupt
conditions have their own corresponding enable bits,
while the two receiver interrupt conditions have a
shared enable bit. These enable bits can be used to
mask out individual UART interrupt sources.
The address detect condition, which is also a UART
interrupt source, does not have an associated flag,
but will generate a UART interrupt when an address
detect condition occurs if its function is enabled by
setting the ADDEN bit in the UCR2 register. An RX pin
wake-up, which is also a UART interrupt source, does
not have an associated flag, but will generate a UART
interrupt if the microcontroller is woken up by a low going edge on the RX pin, if the WAKE and RIE bits in
the UCR2 register are set. Note that in the event of an
RX wake-up interrupt occurring, there will be a delay
of 1024 system clock cycles before the system resumes normal operation.
Note that the USR register flags are read only and
cannot be cleared or set by the application program,
neither will they be cleared when the program jumps
to the corresponding interrupt servicing routine, as is
the case for some of the other interrupts. The flags will
be cleared automatically when certain actions are
taken by the UART, the details of which are given in
the UART register section. The overall UART interrupt
can be disabled or enabled by the EURI bit in the
INTC1 interrupt control register to prevent a UART interrupt from occurring.
ADDEN
0
0
1
Ö
1
Ö
0
X
1
Ö
ADDEN Bit Function
· UART operation in power down mode
When the MCU is in the Power Down Mode the UART
will cease to function. When the device enters the
Power Down Mode, all clock sources to the module
are shutdown. If the MCU enters the Power Down
Mode while a transmission is still in progress, then the
transmission will be terminated and the external TX
transmit pin will be forced to a logic high level. In a
similar way, if the MCU enters the Power Down Mode
while receiving data, then the reception of data will
likewise be terminated. When the MCU enters the
Power Down Mode, note that the USR, UCR1, UCR2,
transmit and receive registers, as well as the BRG
register will not be affected.
The UART function contains a receiver RX pin
wake-up function, which is enabled or disabled by the
WAKE bit in the UCR2 register. If this bit, along with
the UART enable bit, UARTEN, the receiver enable
bit, RXEN and the receiver interrupt bit, RIE, are all
set before the MCU enters the Power Down Mode,
then a falling edge on the RX pin will wake-up the
MCU from the Power Down Mode. Note that as it
takes 1024 system clock cycles after a wake-up, before normal microcontroller operation resumes, any
data received during this time on the RX pin will be ignored.
For a UART wake-up interrupt to occur, in addition to
the bits for the wake-up being set, the global interrupt
enable bit, EMI, and the UART interrupt enable bit,
EURI must also be set. If these two bits are not set
then only a wake up event will occur and no interrupt
will be generated. Note also that as it takes 1024 system clock cycles after a wake-up before normal
microcontroller resumes, the UART interrupt will not
be generated until after this time has elapsed.
· Address detect mode
Setting the Address Detect Mode bit, ADDEN, in the
UCR2 register, enables this special mode. If this bit is
enabled then an additional qualifier will be placed on
the generation of a Receiver Data Available interrupt,
which is requested by the RXIF flag. If the ADDEN bit
is enabled, then when data is available, an interrupt
will only be generated, if the highest received bit has a
high value. Note that the EURI and EMI interrupt enable bits must also be enabled for correct interrupt
generation. This highest address bit is the 9th bit if
BNO=1 or the 8th bit if BNO=0. If this bit is high, then
the received word will be defined as an address rather
than data. A Data Available interrupt will be generated
every time the last bit of the received word is set. If the
ADDEN bit is not enabled, then a Receiver Data Available interrupt will be generated each time the RXIF
flag is set, irrespective of the data last bit status. The
address detect mode and parity enable are mutually
exclusive functions. Therefore if the address detect
mode is enabled, then to ensure correct operation, the
parity function should be disabled by resetting the parity enable bit to zero.
Rev. 1.00
Bit 9 if BNO=1, UART Interrupt
Bit 8 if BNO=0
Generated
38
April 23, 2008
HT46RU232
Options
The following shows kinds of options in the device. ALL the options must be defined to ensure proper system function.
Options
OSC type selection.
This option is to decide if an RC or crystal oscillator is chosen as system clock.
WDT source selection.
There are three types of selection: on-chip RC oscillator, instruction clock or disable the WDT.
CLRWDT times selection.
This option defines how to clear the WDT by instruction. ²One time² means that the CLR WDT instruction can clear
the WDT. ²Two times² means only if both of the CLR WDT1 and CLR WDT2 instructions have been executed, then
WDT can be cleared.
Wake-up selection.
This option defines the wake-up function activity. External I/O pins (PA only) all have the capability to wake-up the
chip from a HALT by a falling edge. (Bit option)
Pull-high selection.
This option is to decide whether a pull-high resistance is visible or not in the input mode of the I/O ports. PA, PB, PC,
PD and PF are bit option.
PFD selection.
If PA3 is set as PFD output, there are two types of selections; One is PFD0 as the PFD output, the other is PFD1 as
the PFD output. PFD0, PFD1 are the timer overflow signals of the Timer/Event Counter 0, Timer/Event Counter 1 respectively.
PWM selection: (7+1) or (6+2) mode
PD0: level output or PWM0 output
PD1: level output or PWM1 output
PD2: level output or PWM2 output
PD3: level output or PWM3 output
WDT time-out period selection.
212/fS~213/fS, 213/fS~214/fS, 214/fS~215/fS, 215/fS~216/fS.
I2C Bus function: enable or disable
LVR selection.
LVR has enable or disable options
Rev. 1.00
39
April 23, 2008
HT46RU232
Application Circuits
V
D D
V D D
R e s e t
C ir c u it
1 0 0 k W
0 .1 m F
0 .1 m F
V S S
V
P B 0 /A N 0
P B 7 /A N 7
~
R E S
P A 0 ~ P A 2
P A 3 /P F D
P A 4
P A 5 /IN T
P A 6 /S D A
P A 7 /S C L
D D
4 7 0 p F
P C 0 /T X
P C 1 /R X
P C 2 ~ P C 7
R
O S C
fS
Y S
/4
R C S y s te m O s c illa to r
3 0 k W < R O S C < 7 5 0 k W
O S C 2
~
P D 0 /P W M 0
P D 3 /P W M 3
O S C 1
C 1
O S C 1
P D 4 ~ P D 7
O S C
C ir c u it
O S C 1
P F 0 ~ P F 7
O S C 2
T M R 0
T M R 1
C 2
R 1
H T 4 6 R U 2 3 2
O S C 2
O S C
C r y s ta l/R e s o n a to r
S y s te m O s c illa to r
F o r R 1 , C 1 , C 2 s e e n o te
C ir c u it
Note: 1. Crystal/resonator system oscillators
For crystal oscillators, C1 and C2 are only required for some crystal frequencies to ensure oscillation. For
resonator applications C1 and C2 are normally required for oscillation to occur. For most applications it is not
necessary to add R1. However if the LVR function is disabled, and if it is required to stop the oscillator when
VDD falls below its operating range, it is recommended that R1 is added. The values of C1 and C2 should be
selected in consultation with the crystal/resonator manufacturer specifications.
2. Reset circuit
The reset circuit resistance and capacitance values should be chosen to ensure that VDD is stable and remains within its operating voltage range before the RES pin reaches a high level. Ensure that the length of
the wiring connected to the RES pin is kept as short as possible, to avoid noise interference.
3. For applications where noise may interfere with the reset circuit and for details on the oscillator external components, refer to Application Note HA0075E for more information.
Rev. 1.00
40
April 23, 2008
HT46RU232
Instruction Set
subtract instruction mnemonics to enable the necessary
arithmetic to be carried out. Care must be taken to ensure correct handling of carry and borrow data when results exceed 255 for addition and less than 0 for
subtraction. The increment and decrement instructions
INC, INCA, DEC and DECA provide a simple means of
increasing or decreasing by a value of one of the values
in the destination specified.
Introduction
Central to the successful operation of any
microcontroller is its instruction set, which is a set of program instruction codes that directs the microcontroller to
perform certain operations. In the case of Holtek
microcontrollers, a comprehensive and flexible set of
over 60 instructions is provided to enable programmers
to implement their application with the minimum of programming overheads.
Logical and Rotate Operations
For easier understanding of the various instruction
codes, they have been subdivided into several functional groupings.
The standard logical operations such as AND, OR, XOR
and CPL all have their own instruction within the Holtek
microcontroller instruction set. As with the case of most
instructions involving data manipulation, data must pass
through the Accumulator which may involve additional
programming steps. In all logical data operations, the
zero flag may be set if the result of the operation is zero.
Another form of logical data manipulation comes from
the rotate instructions such as RR, RL, RRC and RLC
which provide a simple means of rotating one bit right or
left. Different rotate instructions exist depending on program requirements. Rotate instructions are useful for
serial port programming applications where data can be
rotated from an internal register into the Carry bit from
where it can be examined and the necessary serial bit
set high or low. Another application where rotate data
operations are used is to implement multiplication and
division calculations.
Instruction Timing
Most instructions are implemented within one instruction cycle. The exceptions to this are branch, call, or table read instructions where two instruction cycles are
required. One instruction cycle is equal to 4 system
clock cycles, therefore in the case of an 8MHz system
oscillator, most instructions would be implemented
within 0.5ms and branch or call instructions would be implemented within 1ms. Although instructions which require one more cycle to implement are generally limited
to the JMP, CALL, RET, RETI and table read instructions, it is important to realize that any other instructions
which involve manipulation of the Program Counter Low
register or PCL will also take one more cycle to implement. As instructions which change the contents of the
PCL will imply a direct jump to that new address, one
more cycle will be required. Examples of such instructions would be ²CLR PCL² or ²MOV PCL, A². For the
case of skip instructions, it must be noted that if the result of the comparison involves a skip operation then
this will also take one more cycle, if no skip is involved
then only one cycle is required.
Branches and Control Transfer
Program branching takes the form of either jumps to
specified locations using the JMP instruction or to a subroutine using the CALL instruction. They differ in the
sense that in the case of a subroutine call, the program
must return to the instruction immediately when the subroutine has been carried out. This is done by placing a
return instruction RET in the subroutine which will cause
the program to jump back to the address right after the
CALL instruction. In the case of a JMP instruction, the
program simply jumps to the desired location. There is
no requirement to jump back to the original jumping off
point as in the case of the CALL instruction. One special
and extremely useful set of branch instructions are the
conditional branches. Here a decision is first made regarding the condition of a certain data memory or individual bits. Depending upon the conditions, the program
will continue with the next instruction or skip over it and
jump to the following instruction. These instructions are
the key to decision making and branching within the program perhaps determined by the condition of certain input switches or by the condition of internal data bits.
Moving and Transferring Data
The transfer of data within the microcontroller program
is one of the most frequently used operations. Making
use of three kinds of MOV instructions, data can be
transferred from registers to the Accumulator and
vice-versa as well as being able to move specific immediate data directly into the Accumulator. One of the most
important data transfer applications is to receive data
from the input ports and transfer data to the output ports.
Arithmetic Operations
The ability to perform certain arithmetic operations and
data manipulation is a necessary feature of most
microcontroller applications. Within the Holtek
microcontroller instruction set are a range of add and
Rev. 1.00
41
April 23, 2008
HT46RU232
Bit Operations
Other Operations
The ability to provide single bit operations on Data Memory is an extremely flexible feature of all Holtek
microcontrollers. This feature is especially useful for
output port bit programming where individual bits or port
pins can be directly set high or low using either the ²SET
[m].i² or ²CLR [m].i² instructions respectively. The feature removes the need for programmers to first read the
8-bit output port, manipulate the input data to ensure
that other bits are not changed and then output the port
with the correct new data. This read-modify-write process is taken care of automatically when these bit operation instructions are used.
In addition to the above functional instructions, a range
of other instructions also exist such as the ²HALT² instruction for Power-down operations and instructions to
control the operation of the Watchdog Timer for reliable
program operations under extreme electric or electromagnetic environments. For their relevant operations,
refer to the functional related sections.
Instruction Set Summary
The following table depicts a summary of the instruction
set categorised according to function and can be consulted as a basic instruction reference using the following listed conventions.
Table Read Operations
Table conventions:
Data storage is normally implemented by using registers. However, when working with large amounts of
fixed data, the volume involved often makes it inconvenient to store the fixed data in the Data Memory. To overcome this problem, Holtek microcontrollers allow an
area of Program Memory to be setup as a table where
data can be directly stored. A set of easy to use instructions provides the means by which this fixed data can be
referenced and retrieved from the Program Memory.
Mnemonic
x: Bits immediate data
m: Data Memory address
A: Accumulator
i: 0~7 number of bits
addr: Program memory address
Description
Cycles
Flag Affected
1
1Note
1
1
1Note
1
1
1Note
1
1Note
1Note
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
Z, C, AC, OV
C
1
1
1
1Note
1Note
1Note
1
1
1
1Note
1
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
Z
1
1Note
1
1Note
Z
Z
Z
Z
Arithmetic
ADD A,[m]
ADDM A,[m]
ADD A,x
ADC A,[m]
ADCM A,[m]
SUB A,x
SUB A,[m]
SUBM A,[m]
SBC A,[m]
SBCM A,[m]
DAA [m]
Add Data Memory to ACC
Add ACC to Data Memory
Add immediate data to ACC
Add Data Memory to ACC with Carry
Add ACC to Data memory with Carry
Subtract immediate data from the ACC
Subtract Data Memory from ACC
Subtract Data Memory from ACC with result in Data Memory
Subtract Data Memory from ACC with Carry
Subtract Data Memory from ACC with Carry, result in Data Memory
Decimal adjust ACC for Addition with result in Data Memory
Logic Operation
AND A,[m]
OR A,[m]
XOR A,[m]
ANDM A,[m]
ORM A,[m]
XORM A,[m]
AND A,x
OR A,x
XOR A,x
CPL [m]
CPLA [m]
Logical AND Data Memory to ACC
Logical OR Data Memory to ACC
Logical XOR Data Memory to ACC
Logical AND ACC to Data Memory
Logical OR ACC to Data Memory
Logical XOR ACC to Data Memory
Logical AND immediate Data to ACC
Logical OR immediate Data to ACC
Logical XOR immediate Data to ACC
Complement Data Memory
Complement Data Memory with result in ACC
Increment & Decrement
INCA [m]
INC [m]
DECA [m]
DEC [m]
Rev. 1.00
Increment Data Memory with result in ACC
Increment Data Memory
Decrement Data Memory with result in ACC
Decrement Data Memory
42
April 23, 2008
HT46RU232
Mnemonic
Description
Cycles
Flag Affected
Rotate Data Memory right with result in ACC
Rotate Data Memory right
Rotate Data Memory right through Carry with result in ACC
Rotate Data Memory right through Carry
Rotate Data Memory left with result in ACC
Rotate Data Memory left
Rotate Data Memory left through Carry with result in ACC
Rotate Data Memory left through Carry
1
1Note
1
1Note
1
1Note
1
1Note
None
None
C
C
None
None
C
C
Move Data Memory to ACC
Move ACC to Data Memory
Move immediate data to ACC
1
1Note
1
None
None
None
Clear bit of Data Memory
Set bit of Data Memory
1Note
1Note
None
None
Jump unconditionally
Skip if Data Memory is zero
Skip if Data Memory is zero with data movement to ACC
Skip if bit i of Data Memory is zero
Skip if bit i of Data Memory is not zero
Skip if increment Data Memory is zero
Skip if decrement Data Memory is zero
Skip if increment Data Memory is zero with result in ACC
Skip if decrement Data Memory is zero with result in ACC
Subroutine call
Return from subroutine
Return from subroutine and load immediate data to ACC
Return from interrupt
2
1Note
1note
1Note
1Note
1Note
1Note
1Note
1Note
2
2
2
2
None
None
None
None
None
None
None
None
None
None
None
None
None
Read table (current page) to TBLH and Data Memory
Read table (last page) to TBLH and Data Memory
2Note
2Note
None
None
No operation
Clear Data Memory
Set Data Memory
Clear Watchdog Timer
Pre-clear Watchdog Timer
Pre-clear Watchdog Timer
Swap nibbles of Data Memory
Swap nibbles of Data Memory with result in ACC
Enter power down mode
1
1Note
1Note
1
1
1
1Note
1
1
None
None
None
TO, PDF
TO, PDF
TO, PDF
None
None
TO, PDF
Rotate
RRA [m]
RR [m]
RRCA [m]
RRC [m]
RLA [m]
RL [m]
RLCA [m]
RLC [m]
Data Move
MOV A,[m]
MOV [m],A
MOV A,x
Bit Operation
CLR [m].i
SET [m].i
Branch
JMP addr
SZ [m]
SZA [m]
SZ [m].i
SNZ [m].i
SIZ [m]
SDZ [m]
SIZA [m]
SDZA [m]
CALL addr
RET
RET A,x
RETI
Table Read
TABRDC [m]
TABRDL [m]
Miscellaneous
NOP
CLR [m]
SET [m]
CLR WDT
CLR WDT1
CLR WDT2
SWAP [m]
SWAPA [m]
HALT
Note:
1. For skip instructions, if the result of the comparison involves a skip then two cycles are required,
if no skip takes place only one cycle is required.
2. Any instruction which changes the contents of the PCL will also require 2 cycles for execution.
3. For the ²CLR WDT1² and ²CLR WDT2² instructions the TO and PDF flags may be affected by
the execution status. The TO and PDF flags are cleared after both ²CLR WDT1² and
²CLR WDT2² instructions are consecutively executed. Otherwise the TO and PDF flags
remain unchanged.
Rev. 1.00
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April 23, 2008
HT46RU232
Instruction Definition
ADC A,[m]
Add Data Memory to ACC with Carry
Description
The contents of the specified Data Memory, Accumulator and the carry flag are added. The
result is stored in the Accumulator.
Operation
ACC ¬ ACC + [m] + C
Affected flag(s)
OV, Z, AC, C
ADCM A,[m]
Add ACC to Data Memory with Carry
Description
The contents of the specified Data Memory, Accumulator and the carry flag are added. The
result is stored in the specified Data Memory.
Operation
[m] ¬ ACC + [m] + C
Affected flag(s)
OV, Z, AC, C
ADD A,[m]
Add Data Memory to ACC
Description
The contents of the specified Data Memory and the Accumulator are added. The result is
stored in the Accumulator.
Operation
ACC ¬ ACC + [m]
Affected flag(s)
OV, Z, AC, C
ADD A,x
Add immediate data to ACC
Description
The contents of the Accumulator and the specified immediate data are added. The result is
stored in the Accumulator.
Operation
ACC ¬ ACC + x
Affected flag(s)
OV, Z, AC, C
ADDM A,[m]
Add ACC to Data Memory
Description
The contents of the specified Data Memory and the Accumulator are added. The result is
stored in the specified Data Memory.
Operation
[m] ¬ ACC + [m]
Affected flag(s)
OV, Z, AC, C
AND A,[m]
Logical AND Data Memory to ACC
Description
Data in the Accumulator and the specified Data Memory perform a bitwise logical AND operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²AND² [m]
Affected flag(s)
Z
AND A,x
Logical AND immediate data to ACC
Description
Data in the Accumulator and the specified immediate data perform a bitwise logical AND
operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²AND² x
Affected flag(s)
Z
ANDM A,[m]
Logical AND ACC to Data Memory
Description
Data in the specified Data Memory and the Accumulator perform a bitwise logical AND operation. The result is stored in the Data Memory.
Operation
[m] ¬ ACC ²AND² [m]
Affected flag(s)
Z
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HT46RU232
CALL addr
Subroutine call
Description
Unconditionally calls a subroutine at the specified address. The Program Counter then increments by 1 to obtain the address of the next instruction which is then pushed onto the
stack. The specified address is then loaded and the program continues execution from this
new address. As this instruction requires an additional operation, it is a two cycle instruction.
Operation
Stack ¬ Program Counter + 1
Program Counter ¬ addr
Affected flag(s)
None
CLR [m]
Clear Data Memory
Description
Each bit of the specified Data Memory is cleared to 0.
Operation
[m] ¬ 00H
Affected flag(s)
None
CLR [m].i
Clear bit of Data Memory
Description
Bit i of the specified Data Memory is cleared to 0.
Operation
[m].i ¬ 0
Affected flag(s)
None
CLR WDT
Clear Watchdog Timer
Description
The TO, PDF flags and the WDT are all cleared.
Operation
WDT cleared
TO ¬ 0
PDF ¬ 0
Affected flag(s)
TO, PDF
CLR WDT1
Pre-clear Watchdog Timer
Description
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in conjunction with CLR WDT2 and must be executed alternately with CLR WDT2 to have effect. Repetitively executing this instruction without alternately executing CLR WDT2 will have no
effect.
Operation
WDT cleared
TO ¬ 0
PDF ¬ 0
Affected flag(s)
TO, PDF
CLR WDT2
Pre-clear Watchdog Timer
Description
The TO, PDF flags and the WDT are all cleared. Note that this instruction works in conjunction with CLR WDT1 and must be executed alternately with CLR WDT1 to have effect. Repetitively executing this instruction without alternately executing CLR WDT1 will have no
effect.
Operation
WDT cleared
TO ¬ 0
PDF ¬ 0
Affected flag(s)
TO, PDF
Rev. 1.00
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April 23, 2008
HT46RU232
CPL [m]
Complement Data Memory
Description
Each bit of the specified Data Memory is logically complemented (1¢s complement). Bits
which previously contained a 1 are changed to 0 and vice versa.
Operation
[m] ¬ [m]
Affected flag(s)
Z
CPLA [m]
Complement Data Memory with result in ACC
Description
Each bit of the specified Data Memory is logically complemented (1¢s complement). Bits
which previously contained a 1 are changed to 0 and vice versa. The complemented result
is stored in the Accumulator and the contents of the Data Memory remain unchanged.
Operation
ACC ¬ [m]
Affected flag(s)
Z
DAA [m]
Decimal-Adjust ACC for addition with result in Data Memory
Description
Convert the contents of the Accumulator value to a BCD ( Binary Coded Decimal) value resulting from the previous addition of two BCD variables. If the low nibble is greater than 9 or
if AC flag is set, then a value of 6 will be added to the low nibble. Otherwise the low nibble
remains unchanged. If the high nibble is greater than 9 or if the C flag is set, then a value of
6 will be added to the high nibble. Essentially, the decimal conversion is performed by adding 00H, 06H, 60H or 66H depending on the Accumulator and flag conditions. Only the C
flag may be affected by this instruction which indicates that if the original BCD sum is
greater than 100, it allows multiple precision decimal addition.
Operation
[m] ¬ ACC + 00H or
[m] ¬ ACC + 06H or
[m] ¬ ACC + 60H or
[m] ¬ ACC + 66H
Affected flag(s)
C
DEC [m]
Decrement Data Memory
Description
Data in the specified Data Memory is decremented by 1.
Operation
[m] ¬ [m] - 1
Affected flag(s)
Z
DECA [m]
Decrement Data Memory with result in ACC
Description
Data in the specified Data Memory is decremented by 1. The result is stored in the Accumulator. The contents of the Data Memory remain unchanged.
Operation
ACC ¬ [m] - 1
Affected flag(s)
Z
HALT
Enter power down mode
Description
This instruction stops the program execution and turns off the system clock. The contents
of the Data Memory and registers are retained. The WDT and prescaler are cleared. The
power down flag PDF is set and the WDT time-out flag TO is cleared.
Operation
TO ¬ 0
PDF ¬ 1
Affected flag(s)
TO, PDF
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April 23, 2008
HT46RU232
INC [m]
Increment Data Memory
Description
Data in the specified Data Memory is incremented by 1.
Operation
[m] ¬ [m] + 1
Affected flag(s)
Z
INCA [m]
Increment Data Memory with result in ACC
Description
Data in the specified Data Memory is incremented by 1. The result is stored in the Accumulator. The contents of the Data Memory remain unchanged.
Operation
ACC ¬ [m] + 1
Affected flag(s)
Z
JMP addr
Jump unconditionally
Description
The contents of the Program Counter are replaced with the specified address. Program
execution then continues from this new address. As this requires the insertion of a dummy
instruction while the new address is loaded, it is a two cycle instruction.
Operation
Program Counter ¬ addr
Affected flag(s)
None
MOV A,[m]
Move Data Memory to ACC
Description
The contents of the specified Data Memory are copied to the Accumulator.
Operation
ACC ¬ [m]
Affected flag(s)
None
MOV A,x
Move immediate data to ACC
Description
The immediate data specified is loaded into the Accumulator.
Operation
ACC ¬ x
Affected flag(s)
None
MOV [m],A
Move ACC to Data Memory
Description
The contents of the Accumulator are copied to the specified Data Memory.
Operation
[m] ¬ ACC
Affected flag(s)
None
NOP
No operation
Description
No operation is performed. Execution continues with the next instruction.
Operation
No operation
Affected flag(s)
None
OR A,[m]
Logical OR Data Memory to ACC
Description
Data in the Accumulator and the specified Data Memory perform a bitwise logical OR operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²OR² [m]
Affected flag(s)
Z
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April 23, 2008
HT46RU232
OR A,x
Logical OR immediate data to ACC
Description
Data in the Accumulator and the specified immediate data perform a bitwise logical OR operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²OR² x
Affected flag(s)
Z
ORM A,[m]
Logical OR ACC to Data Memory
Description
Data in the specified Data Memory and the Accumulator perform a bitwise logical OR operation. The result is stored in the Data Memory.
Operation
[m] ¬ ACC ²OR² [m]
Affected flag(s)
Z
RET
Return from subroutine
Description
The Program Counter is restored from the stack. Program execution continues at the restored address.
Operation
Program Counter ¬ Stack
Affected flag(s)
None
RET A,x
Return from subroutine and load immediate data to ACC
Description
The Program Counter is restored from the stack and the Accumulator loaded with the
specified immediate data. Program execution continues at the restored address.
Operation
Program Counter ¬ Stack
ACC ¬ x
Affected flag(s)
None
RETI
Return from interrupt
Description
The Program Counter is restored from the stack and the interrupts are re-enabled by setting the EMI bit. EMI is the master interrupt global enable bit. If an interrupt was pending
when the RETI instruction is executed, the pending Interrupt routine will be processed before returning to the main program.
Operation
Program Counter ¬ Stack
EMI ¬ 1
Affected flag(s)
None
RL [m]
Rotate Data Memory left
Description
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit
0.
Operation
[m].(i+1) ¬ [m].i; (i = 0~6)
[m].0 ¬ [m].7
Affected flag(s)
None
RLA [m]
Rotate Data Memory left with result in ACC
Description
The contents of the specified Data Memory are rotated left by 1 bit with bit 7 rotated into bit
0. The rotated result is stored in the Accumulator and the contents of the Data Memory remain unchanged.
Operation
ACC.(i+1) ¬ [m].i; (i = 0~6)
ACC.0 ¬ [m].7
Affected flag(s)
None
Rev. 1.00
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April 23, 2008
HT46RU232
RLC [m]
Rotate Data Memory left through Carry
Description
The contents of the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7
replaces the Carry bit and the original carry flag is rotated into bit 0.
Operation
[m].(i+1) ¬ [m].i; (i = 0~6)
[m].0 ¬ C
C ¬ [m].7
Affected flag(s)
C
RLCA [m]
Rotate Data Memory left through Carry with result in ACC
Description
Data in the specified Data Memory and the carry flag are rotated left by 1 bit. Bit 7 replaces
the Carry bit and the original carry flag is rotated into the bit 0. The rotated result is stored in
the Accumulator and the contents of the Data Memory remain unchanged.
Operation
ACC.(i+1) ¬ [m].i; (i = 0~6)
ACC.0 ¬ C
C ¬ [m].7
Affected flag(s)
C
RR [m]
Rotate Data Memory right
Description
The contents of the specified Data Memory are rotated right by 1 bit with bit 0 rotated into
bit 7.
Operation
[m].i ¬ [m].(i+1); (i = 0~6)
[m].7 ¬ [m].0
Affected flag(s)
None
RRA [m]
Rotate Data Memory right with result in ACC
Description
Data in the specified Data Memory and the carry flag are rotated right by 1 bit with bit 0 rotated into bit 7. The rotated result is stored in the Accumulator and the contents of the Data
Memory remain unchanged.
Operation
ACC.i ¬ [m].(i+1); (i = 0~6)
ACC.7 ¬ [m].0
Affected flag(s)
None
RRC [m]
Rotate Data Memory right through Carry
Description
The contents of the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0
replaces the Carry bit and the original carry flag is rotated into bit 7.
Operation
[m].i ¬ [m].(i+1); (i = 0~6)
[m].7 ¬ C
C ¬ [m].0
Affected flag(s)
C
RRCA [m]
Rotate Data Memory right through Carry with result in ACC
Description
Data in the specified Data Memory and the carry flag are rotated right by 1 bit. Bit 0 replaces the Carry bit and the original carry flag is rotated into bit 7. The rotated result is
stored in the Accumulator and the contents of the Data Memory remain unchanged.
Operation
ACC.i ¬ [m].(i+1); (i = 0~6)
ACC.7 ¬ C
C ¬ [m].0
Affected flag(s)
C
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April 23, 2008
HT46RU232
SBC A,[m]
Subtract Data Memory from ACC with Carry
Description
The contents of the specified Data Memory and the complement of the carry flag are subtracted from the Accumulator. The result is stored in the Accumulator. Note that if the result
of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or
zero, the C flag will be set to 1.
Operation
ACC ¬ ACC - [m] - C
Affected flag(s)
OV, Z, AC, C
SBCM A,[m]
Subtract Data Memory from ACC with Carry and result in Data Memory
Description
The contents of the specified Data Memory and the complement of the carry flag are subtracted from the Accumulator. The result is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is
positive or zero, the C flag will be set to 1.
Operation
[m] ¬ ACC - [m] - C
Affected flag(s)
OV, Z, AC, C
SDZ [m]
Skip if decrement Data Memory is 0
Description
The contents of the specified Data Memory are first decremented by 1. If the result is 0 the
following instruction is skipped. As this requires the insertion of a dummy instruction while
the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program
proceeds with the following instruction.
Operation
[m] ¬ [m] - 1
Skip if [m] = 0
Affected flag(s)
None
SDZA [m]
Skip if decrement Data Memory is zero with result in ACC
Description
The contents of the specified Data Memory are first decremented by 1. If the result is 0, the
following instruction is skipped. The result is stored in the Accumulator but the specified
Data Memory contents remain unchanged. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not
0, the program proceeds with the following instruction.
Operation
ACC ¬ [m] - 1
Skip if ACC = 0
Affected flag(s)
None
SET [m]
Set Data Memory
Description
Each bit of the specified Data Memory is set to 1.
Operation
[m] ¬ FFH
Affected flag(s)
None
SET [m].i
Set bit of Data Memory
Description
Bit i of the specified Data Memory is set to 1.
Operation
[m].i ¬ 1
Affected flag(s)
None
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April 23, 2008
HT46RU232
SIZ [m]
Skip if increment Data Memory is 0
Description
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the
following instruction is skipped. As this requires the insertion of a dummy instruction while
the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the program
proceeds with the following instruction.
Operation
[m] ¬ [m] + 1
Skip if [m] = 0
Affected flag(s)
None
SIZA [m]
Skip if increment Data Memory is zero with result in ACC
Description
The contents of the specified Data Memory are first incremented by 1. If the result is 0, the
following instruction is skipped. The result is stored in the Accumulator but the specified
Data Memory contents remain unchanged. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not
0 the program proceeds with the following instruction.
Operation
ACC ¬ [m] + 1
Skip if ACC = 0
Affected flag(s)
None
SNZ [m].i
Skip if bit i of Data Memory is not 0
Description
If bit i of the specified Data Memory is not 0, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two
cycle instruction. If the result is 0 the program proceeds with the following instruction.
Operation
Skip if [m].i ¹ 0
Affected flag(s)
None
SUB A,[m]
Subtract Data Memory from ACC
Description
The specified Data Memory is subtracted from the contents of the Accumulator. The result
is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will
be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
Operation
ACC ¬ ACC - [m]
Affected flag(s)
OV, Z, AC, C
SUBM A,[m]
Subtract Data Memory from ACC with result in Data Memory
Description
The specified Data Memory is subtracted from the contents of the Accumulator. The result
is stored in the Data Memory. Note that if the result of subtraction is negative, the C flag will
be cleared to 0, otherwise if the result is positive or zero, the C flag will be set to 1.
Operation
[m] ¬ ACC - [m]
Affected flag(s)
OV, Z, AC, C
SUB A,x
Subtract immediate data from ACC
Description
The immediate data specified by the code is subtracted from the contents of the Accumulator. The result is stored in the Accumulator. Note that if the result of subtraction is negative, the C flag will be cleared to 0, otherwise if the result is positive or zero, the C flag will
be set to 1.
Operation
ACC ¬ ACC - x
Affected flag(s)
OV, Z, AC, C
Rev. 1.00
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April 23, 2008
HT46RU232
SWAP [m]
Swap nibbles of Data Memory
Description
The low-order and high-order nibbles of the specified Data Memory are interchanged.
Operation
[m].3~[m].0 « [m].7 ~ [m].4
Affected flag(s)
None
SWAPA [m]
Swap nibbles of Data Memory with result in ACC
Description
The low-order and high-order nibbles of the specified Data Memory are interchanged. The
result is stored in the Accumulator. The contents of the Data Memory remain unchanged.
Operation
ACC.3 ~ ACC.0 ¬ [m].7 ~ [m].4
ACC.7 ~ ACC.4 ¬ [m].3 ~ [m].0
Affected flag(s)
None
SZ [m]
Skip if Data Memory is 0
Description
If the contents of the specified Data Memory is 0, the following instruction is skipped. As
this requires the insertion of a dummy instruction while the next instruction is fetched, it is a
two cycle instruction. If the result is not 0 the program proceeds with the following instruction.
Operation
Skip if [m] = 0
Affected flag(s)
None
SZA [m]
Skip if Data Memory is 0 with data movement to ACC
Description
The contents of the specified Data Memory are copied to the Accumulator. If the value is
zero, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two cycle instruction. If the result is not 0 the
program proceeds with the following instruction.
Operation
ACC ¬ [m]
Skip if [m] = 0
Affected flag(s)
None
SZ [m].i
Skip if bit i of Data Memory is 0
Description
If bit i of the specified Data Memory is 0, the following instruction is skipped. As this requires the insertion of a dummy instruction while the next instruction is fetched, it is a two
cycle instruction. If the result is not 0, the program proceeds with the following instruction.
Operation
Skip if [m].i = 0
Affected flag(s)
None
TABRDC [m]
Read table (current page) to TBLH and Data Memory
Description
The low byte of the program code (current page) addressed by the table pointer (TBLP) is
moved to the specified Data Memory and the high byte moved to TBLH.
Operation
[m] ¬ program code (low byte)
TBLH ¬ program code (high byte)
Affected flag(s)
None
TABRDL [m]
Read table (last page) to TBLH and Data Memory
Description
The low byte of the program code (last page) addressed by the table pointer (TBLP) is
moved to the specified Data Memory and the high byte moved to TBLH.
Operation
[m] ¬ program code (low byte)
TBLH ¬ program code (high byte)
Affected flag(s)
None
Rev. 1.00
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April 23, 2008
HT46RU232
XOR A,[m]
Logical XOR Data Memory to ACC
Description
Data in the Accumulator and the specified Data Memory perform a bitwise logical XOR operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²XOR² [m]
Affected flag(s)
Z
XORM A,[m]
Logical XOR ACC to Data Memory
Description
Data in the specified Data Memory and the Accumulator perform a bitwise logical XOR operation. The result is stored in the Data Memory.
Operation
[m] ¬ ACC ²XOR² [m]
Affected flag(s)
Z
XOR A,x
Logical XOR immediate data to ACC
Description
Data in the Accumulator and the specified immediate data perform a bitwise logical XOR
operation. The result is stored in the Accumulator.
Operation
ACC ¬ ACC ²XOR² x
Affected flag(s)
Z
Rev. 1.00
53
April 23, 2008
HT46RU232
Package Information
28-pin SKDIP (300mil) Outline Dimensions
A
B
2 8
1 5
1
1 4
H
C
D
E
Symbol
Rev. 1.00
F
a
G
I
Dimensions in mil
Min.
Nom.
Max.
A
1375
¾
1395
B
278
¾
298
C
125
¾
135
D
125
¾
145
E
16
¾
20
F
50
¾
70
G
¾
100
¾
H
295
¾
315
I
330
¾
375
a
0°
¾
15°
54
April 23, 2008
HT46RU232
28-pin SOP (300mil) Outline Dimensions
2 8
1 5
A
B
1
1 4
C
C '
G
H
D
E
Symbol
Rev. 1.00
a
F
Dimensions in mil
Min.
Nom.
Max.
A
394
¾
419
B
290
¾
300
C
14
¾
20
C¢
697
¾
713
D
92
¾
104
E
¾
50
¾
F
4
¾
¾
G
32
¾
38
H
4
¾
12
a
0°
¾
10°
55
April 23, 2008
HT46RU232
48-pin SSOP (300mil) Outline Dimensions
4 8
2 5
A
B
2 4
1
C
C '
G
H
D
F
E
Symbol
Rev. 1.00
a
Dimensions in mil
Min.
Nom.
Max.
A
395
¾
420
B
291
¾
299
C
8
¾
12
C¢
613
¾
637
D
85
¾
99
E
¾
25
¾
F
4
¾
10
G
25
¾
35
H
4
¾
12
a
0°
¾
8°
56
April 23, 2008
HT46RU232
Product Tape and Reel Specifications
Reel Dimensions
D
T 2
A
C
B
T 1
SOP 28W (300mil)
Symbol
Description
A
Reel Outer Diameter
B
Reel Inner Diameter
Dimensions in mm
330±1.0
62±1.5
13.0+0.5
-0.2
C
Spindle Hole Diameter
D
Key Slit Width
2.0±0.5
T1
Space Between Flange
24.8+0.3
-0.2
T2
Reel Thickness
30.2±0.2
SSOP 48W
Symbol
Description
Dimensions in mm
A
Reel Outer Diameter
330±1.0
B
Reel Inner Diameter
100±0.1
C
Spindle Hole Diameter
13.0+0.5
-0.2
D
Key Slit Width
2.0±0.5
T1
Space Between Flange
32.2+0.3
-0.2
T2
Reel Thickness
38.2±0.2
Rev. 1.00
57
April 23, 2008
HT46RU232
Carrier Tape Dimensions
P 0
D
P 1
t
E
F
W
C
D 1
B 0
P
K 0
A 0
SOP 28W (300mil)
Symbol
Description
Dimensions in mm
W
Carrier Tape Width
24.0±0.3
P
Cavity Pitch
12.0±0.1
E
Perforation Position
1.75±0.1
F
Cavity to Perforation (Width Direction)
11.5±0.1
D
Perforation Diameter
1.5+0.1
D1
Cavity Hole Diameter
1.5+0.25
P0
Perforation Pitch
4.0±0.1
P1
Cavity to Perforation (Length Direction)
2.0±0.1
A0
Cavity Length
10.85±0.1
B0
Cavity Width
18.34±0.1
K0
Cavity Depth
2.97±0.1
t
Carrier Tape Thickness
0.35±0.01
C
Cover Tape Width
Rev. 1.00
21.3
58
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HT46RU232
P 0
D
P 1
t
E
F
W
D 1
C
B 0
K 1
P
K 2
A 0
SSOP 48W
Symbol
Description
Dimensions in mm
W
Carrier Tape Width
32.0±0.3
P
Cavity Pitch
16.0±0.1
E
Perforation Position
1.75±0.1
F
Cavity to Perforation (Width Direction)
14.2±0.1
D
Perforation Diameter
2.0 Min.
D1
Cavity Hole Diameter
1.5+0.25
P0
Perforation Pitch
4.0±0.1
P1
Cavity to Perforation (Length Direction)
2.0±0.1
A0
Cavity Length
12.0±0.1
B0
Cavity Width
16.20±0.1
K1
Cavity Depth
2.4±0.1
K2
Cavity Depth
3.2±0.1
t
Carrier Tape Thickness
C
Cover Tape Width
Rev. 1.00
0.35±0.05
25.5
59
April 23, 2008
HT46RU232
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Copyright Ó 2008 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used
solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable
without further modification, nor recommends the use of its products for application that may present a risk to human life
due to malfunction or otherwise. Holtek¢s products are not authorized for use as critical components in life support devices
or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information,
please visit our web site at http://www.holtek.com.tw.
Rev. 1.00
60
April 23, 2008