157
CHAPTER 7 8-BIT PWM TIMER
7.10
Program Example for PWM Timer
This section describes program examples of an 8-bit PWM timer.
■
Program Example of Interval Timer Functions
●
Processing specifications
•
5 ms interval timer interrupts occur repeatedly.
•
The square waveform that inverts at an interval is output to the P50/PWM pin.
•
The following expression yields the COMR register value for which the interval is about 5 ms when the
top speed of the gear (one instruction cycle = 4/F
CH
) is obtained at an oscillation frequency of 12.5
MHz. The count clock is 64 t
INST
of the internal count clock.
COMR register value = 5 ms/(64
×
4/12.5 MHz) - 1 = 244.1 (0F4
H
)
●
Coding example
CNTR
EQU
0022H
; Address of the PWM control register
COMR
EQU
0023H
; Address of the PWM compare register
TPE
EQU
CNTR:3
; Defining the bit to enable the counter operation
TIR
EQU
CNTR:2
; Defining the interrupt request flag bit
ILR3
EQU
007D
; Address of the register to set the interrupt level
INT_V
DSEG
ABS
; [DATA SEGMENT]
ORG
0FFF8H
IRQ9
DW
WARI1
; Setting the interrupt vector
INT_V
ENDS
;------------------------Main program---------------------------------------------------------------------------------
CSEG
; [CODE SEGMENT]
; The stack pointer (SP) and others are assumed to have
been initialized.
:
CLRI
; Disabling interrupts
CLRB
TPE
; Stopping the counter operation
MOV
ILR3,#11110111B
; Setting the interrupt level (level 1)
MOV
COMR,#0F4H
; Comparison value with the counter value (interval)
MOV
CNTR,#00101011B
; Enabling the output of the PWM
; Interval timer operation, selection of 64 t
INST
; Starting the counter operation and enabling the output
of interrupt requests
SETI
; Enabling interrupts
:
;------------------------Interrupt program----------------------------------------------------------------------------
WARI1
CLRB
TIR
; Clearing the interrupt request flag
PUSHW
A
XCHW
A,T
; Saving A and T
PUSHW
A
Содержание F2MC-8L F202RA
Страница 2: ......
Страница 4: ......
Страница 32: ...16 CHAPTER 1 OVERVIEW ...
Страница 90: ...74 CHAPTER 3 CPU ...
Страница 142: ...126 CHAPTER 5 TIME BASE TIMER POPW A RETI ENDS END ...
Страница 150: ...134 CHAPTER 6 WATCHDOG TIMER ...
Страница 174: ...158 CHAPTER 7 8 BIT PWM TIMER User processing POPW A XCHW A T Restoring A and T POPW A RETI ENDS ...
Страница 176: ...160 CHAPTER 7 8 BIT PWM TIMER ...
Страница 220: ...204 CHAPTER 8 8 16 BIT CAPTURE TIMER COUNTER ...
Страница 240: ...224 CHAPTER 9 12 BIT PPG TIMER ...
Страница 258: ...242 CHAPTER 10 EXTERNAL INTERRUPT CIRCUIT 1 EDGE PUSHW A User processing POPW A XCHW A T POPW A RETI ENDS END ...
Страница 274: ...258 CHAPTER 11 EXTERNAL INTERRUPT CIRCUIT 2 LEVEL ...
Страница 362: ...346 CHAPTER 15 BUZZER OUTPUT ...
Страница 371: ...355 CHAPTER 16 WILD REGISTER FUNCTION 16 3 5 Data Test Set Register WROR A test register Do not access this register ...
Страница 390: ...374 CHAPTER 17 FLASH MEMORY ...
Страница 419: ...403 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Страница 434: ...418 INDEX ...
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