assembly - Stack overflow in Pic16F684 Microcontroller when using Lookup tables -
task develop program blink leds d7 d0.
i have develop solution blinks them once , have stack overflow.
i suspicious on lookup tables becouse previosly have faced error on last trisa configuration(commented now) pasting code.
;********************************************************************************* ; filename: pic_demonstration.asm -it should be! ; author: alexander drabek ; date: 01.05.13 ; description: assembler program pic16f684 turns on , off leds d7 d0 ; delay of 0.5 second ;check if trisa reaching 4th , porta 8 leds. ;to report: ;1.separate pcl in bank1 , bank0 ;2.lookup table , undaestanding of options of code. ;3.we assuming work in bank0 ;4.overflow. list p=16f684 ; list directive define processor #include <p16f684.inc> ; processor specific variable definitions __config _cp_off & _wdt_off & _pwrte_on & _intrc_osc_noclkout & _mclre_off & _cpd_off ;****************************** assignment statements **************************** ;delay counters count1 equ 20h ; store count1 @ address 20h count2 equ 21h ; store count2 @ address 21h normal equ 22h ; store normal @ address 22h - responsible general loop(4 times change trisa) count3 equ 26h ; counter make more delay ;loops counters porta_internal equ 23h ;store porta_internal @ address 21h count_led_number equ 24h ; store count_led_number @ address 21h count_trisa_number equ 25h ; store count_trisa_number @ address 21h ;****************************** "start" of program ****************************** ; initial configuration ;errorlevel -302 ; disable bank switch warning org 0x000 ; processor reset vector bcf status,rp0 ; bank 0 selected movlw 07h ; set ra<2:0> digital , movwf cmcon0 ; comparators turned off bsf status,rp0 ; bank 1 selected clrf ansel ; digital i/o selected movlw b'00111111' ; move in w - 0x3f - set i/o pins digital inputs movwf trisa ; configure i/o ports clrf intcon ; disable interrupts, clear flags bcf status,rp0 ; bank 0 selected clrf porta ; clear outputs ;********************************************************************************* ; load values counters . again;reset value movlw b'11101010' ; first load value of say, f0h in w register movwf count2 ; move count2 register movlw 0x03; ; first load value of say, f0h in w register movwf count3 ; move count2 register movlw b'00000100' ; load value 4, in w register movwf normal ; move normal movlw b'00000010' ; first load value of say, 1 in w register movwf porta_internal ; move porta_internal movlw b'00000000' ; first load value of say, 1 in w register movwf count_led_number ; move count2 register movlw b'00000000' ; first load value of say, 1 in w register movwf count_trisa_number ; move count2 register goto start_loop ;******************************************************************************** ;********************************************************************************* lookup_porta movlw low tableporta addwf count_led_number,0 movwf pcl ; jump specified entry tableporta retlw b'00000010' ; sending high d7 -ok retlw b'00000100' ; sending high d6 -ok retlw b'00000100' ; sending high d5 -ok retlw b'00100000' ; sending high d4 -ok retlw b'00000100' ; sending high d3 -ok retlw b'00010000' ; sending high d2 -ok retlw b'00100000' ; sending high d1 -ok retlw b'00010000' ; sending high d0 -ok-------- lookup_trisa movlw low tabletrisa addwf count_trisa_number,0 movwf pcl ; jump specified entry ; retlw b'00111001'; 57 - overflow! tabletrisa retlw b'00011011'; 27-decimal ; element 0 of lookup table retlw b'00101011'; 43-decimal ; element 1 of lookup table retlw b'00001111'; 15-decimal ; element 2 of lookup table ;it loading first 1 of eac lookup tables! ;********************************************************************************* start_loop ;temporary solution overflow bsf status,rp0 ; bank 1 selected movlw b'00111001' ; trisa d6 , d7 movwf trisa bcf status, rp0 ; bank 0 selected call delay call lookup_porta ; call table. -it should obtain address next memory cell porta config movwf porta ;light diod! call delay ; half second clrf porta ; clear porta incfsz count_led_number,1 ;increase led number! save variable! call delay call lookup_porta ; call table. -it should obtain address next memory cell porta config movwf porta ;light diod! call delay ; half second clrf porta ; clear porta incfsz count_led_number,1 ;end of temporary solution iternal_trisa_loop ;change trisa after 2 diods ,do till end of lookup table call lookup_trisa ; call table. -it should obtain address next memory cell trisa config bsf status,rp0 ;bank 1 movwf trisa ;move config trisa bcf status, rp0 ;reset bank 0 decfsz normal,1 ;decrease number of posible configuration in iteration value of 5 -not sure --it omit las 1 (option 4) goto internal_loop_2diods ; blink 2 diods including delays goto again ; internal_loop_2diods ;develop delay ! +trisa change bcf status, rp0 ; call delay call lookup_porta ; call table. -it should obtain address next memory cell porta config movwf porta ;light diod! call delay ; half second clrf porta ; clear porta incfsz count_led_number,1 ;increase led number! save variable! decfsz porta_internal,1 ; should have value of 2 xd goto internal_loop_2diods ; 1 repeat! incfsz count_trisa_number,1 ;increase trisa config number movlw b'00000010' ; first load value of say, 1 in w register movwf porta_internal ; move count2 register goto iternal_trisa_loop ;- loop forever - goto again ;********************************************************************************* ; delay subroutine ;********************************************************************************* ; generate delay period delay loop1 decfsz count1,1 ; decrement count1 , skip next instruction if 0 goto loop1 ; else loop loop1 decfsz count2,1 ; decrement count2 , skip next instruction if 0 goto loop1 ; else loop loop1 decfsz count3,1 ; decrement count1 , skip next instruction if 0 goto loop1 ; else loop loop1 movlw 0x03 ; reload second counter next iteration movwf count3 ; decrement count3 , skip next instruction if 0 movlw 0xf0 ; reload second counter next iteration movwf count2 return ; else loop loop1 ;********************************************************************************* end ;*********************************************************************************
anyone know wrong? during debuging value each counter seems ok me.
have tried quite new in assembly programming.
your goto lookup table routine made wrong! set pclath before using computed goto. like:
lookup_porta movlw high tableporta movwf pclath movlw low tableporta addwf count_led_number,0 movwf pcl ; jump specified entry tableporta retlw b'00000010' ; sending high d7 -ok retlw b'00000100' ; sending high d6 -ok ... and ensure table tableporta inside 256 byte page.
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