Hi các bác,
Em có viết đoạn chương trình sau để quét 4 con LED, thực tế em lắp mạch và chạy được rồi tuy nhiên khi mô phỏng bằng Proteus 7.2sp6 thì chương trình báo stack underflow, chạy được vài ngắt rồi đứng yên không chịu chạy nữa. Code như dưới đây:
list p=16f628A ; list directive to define processor
#include <p16F628A.inc> ; processor specific variable definitions
errorlevel -302 ; suppress message 302 from list file
__CONFIG _CP_OFF & _DATA_CP_OFF & _LVP_OFF & _BOREN_OFF & _MCLRE_ON & _WDT_OFF & _PWRTE_ON & _INTOSC_OSC_NOCLKOUT
;************************************************* *********************
;***** CONSTANTS DEFINITIONS WRITTEN HERE
w_temp EQU 0x7D ; variable used for context saving
status_temp EQU 0x7E ; variable used for context saving
pclath_temp EQU 0x7F ; variable used for context saving
LED_CTRL_TRIS EQU TRISA
LED_CTRL_PORT EQU PORTA ; dat PORTA la cung la PORT co chan dieu khien quet LED
LED1 EQU 0 ; dat chan RA0 dieu khien LED1
LED2 EQU 1
LED3 EQU 2
LED4 EQU 3
LED_DATA_TRIS EQU TRISB
LED_DATA_PORT EQU PORTB ; dat PORTB la PORT cap data cho LED
;***** VARIABLES DEFINITIONS WRITTEN HERE
ORG 0x20 ;start of general purpose registers
;***** VARIABLES FOR MAIN PROG
LED_COUNT RES 1 ; counter for selecting of LED to send data to
LED4_DATA RES 1 ; LED data register
LED3_DATA RES 1
LED2_DATA RES 1
LED1_DATA RES 1
;************************************************* *********************
ORG 0x000 ; processor reset vector
goto BEGIN ; go to beginning of program
ORG 0x0004
goto INTERRUPT
ORG 0x0005 ; interrupt vector location
;************************************************* *********************
;***** MAIN PROGRAM GOES HERE
BEGIN
movlw 0x07
movwf CMCON ;turn comparators off
Initialise
clrf PORTA
clrf PORTB
clrf INTCON ; disable all Interrupt sources and some Interrupt Flags
SetPorts
bsf STATUS, RP0
movlw 0x00 ; dat cac chan cap DATA cho LED la chan Out
movwf LED_DATA_TRIS
movlw 0x00 ; cac chan dieu khien LED la Out
movwf LED_CTRL_TRIS
bcf STATUS, RP0
Main
;****** ENABLE TIMER0 INTERRUPT
movlw b'10100000'
movwf INTCON ; Enable General Interrupt and Timer0 Interrupt
bsf STATUS, RP0 ; select bank 1
movlw b'11000011'
movwf OPTION_REG ; Initialise Timer0 with 1:16 prescaler
bcf STATUS, RP0 ; select bank 0
;*****
movlw b'10111111' ; so 0
movwf LED4_DATA ; set LED data register number 0
movlw b'10000110' ; so 1
movwf LED3_DATA
movlw b'11011011' ; so 2
movwf LED2_DATA
movlw b'11001111' ; so 3
movwf LED1_DATA
clrf LED_COUNT
goto $
;************************************************* *********************
;***** INTERRUPT SUB-ROUTINES WRITTEN HERE
INTERRUPT
movwf w_temp ; save off current W register contents
movf STATUS, W ; move STATUS register into W register
movwf status_temp ; save off contents of STATUS register
movf PCLATH, W ; move PCLATH register into W register
movwf pclath_temp ; save off contents of PCLATH register
;*****
clrf STATUS ; Chon bank 0
btfsc INTCON, T0IF ; Ngat tran timer0 da xay ra chua?
goto T0_INT
INT_ERROR
goto END_ISR
T0_INT ; Xu ly ngat tran timer0
LED4_OUT
bcf LED_CTRL_PORT, LED1
clrf LED_DATA_PORT
movf LED_COUNT, W
xorlw d'0'
btfss STATUS, Z ; kiem tra xem co dung thu tu LED4 ko?
goto LED3_OUT ; neu ko dung thi qua quet LED3
movf LED4_DATA, W ; neu dung thi quet LED4
movwf LED_DATA_PORT ; send DATA to LED4 (pin RA3 of PORTA)
bsf LED_CTRL_PORT, LED4
incf LED_COUNT, F
goto END_ISR
LED3_OUT
bcf LED_CTRL_PORT, LED4 ; tat LED4
clrf LED_DATA_PORT ; xoa data
movf LED_COUNT, W
xorlw d'1'
btfss STATUS, Z
goto LED2_OUT
movf LED3_DATA, W
movwf LED_DATA_PORT ; send DATA to LED3 (pin RA2 of PORTA)
bsf LED_CTRL_PORT, LED3
incf LED_COUNT, F
goto END_ISR
LED2_OUT
bcf LED_CTRL_PORT, LED3
clrf LED_DATA_PORT
movf LED_COUNT, W
xorlw d'2'
btfss STATUS, Z
goto LED1_OUT
movf LED2_DATA, W
movwf LED_DATA_PORT ; send DATA to LED2 (pin RA1 of PORTA)
bsf LED_CTRL_PORT, LED2
incf LED_COUNT, F
goto END_ISR
LED1_OUT
bcf LED_CTRL_PORT, LED2
clrf LED_DATA_PORT
movf LED_COUNT, W
xorlw d'3'
btfss STATUS, Z
goto END_ISR
movf LED1_DATA, W
movwf LED_DATA_PORT ; send DATA to LED2 (pin RA0 of PORTA)
bsf LED_CTRL_PORT, LED1
clrf LED_COUNT ; reset LED counter
goto END_ISR
END_ISR
bcf INTCON, T0IF ; Xoa co ngat tran timer0
;*****
movf pclath_temp, w ; retrieve copy of PCLATH register
movwf PCLATH ; restore pre-isr PCLATH register contents
movf status_temp, w ; retrieve copy of STATUS register
movwf STATUS ; restore pre-isr STATUS register contents
swapf w_temp, f
swapf w_temp, w ; restore pre-isr W register contents
Retfie ; Return from Interrupt
;************************************************* *********************
END ; directive 'end of program'
Như vậy là proteus ko hỗ trợ ngắt cho PIC16 hở các bác? Hay là chương trình em viết sai? Nếu sai thì sai chỗ nào các bác chỉ dùm em với. Thanks.