Author Topic: PIC programming super noob  (Read 344 times)

oip

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PIC programming super noob
« on: December 03, 2017, 08:53:34 PM »
hey folks

currently building the FV-1 project from DIY stompboxes and i'm stuck at the point of programming the 12F683 PIC it uses to convert pot values to pin voltage for the FV-1 program select pins.

i have the code in what i guess is assembly language,

Code: [Select]
;3 bit glitchless A2D converter
;Version 1 05/09/2011
;          __________
;   VDD ---|        |--- VSS
;       ---| 12F683 |--- Bit 0
; CV In ---|        |--- Bit 1
;       ---|________|--- Bit 2

    list   P=PIC12F683
    #include "P12F683.INC"
     __config (_INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF & _CP_OFF & _IESO_OFF & _FCMEN_OFF & _BOD_OFF)
     
    cblock 0x20
    new
    current
    count
    endc

    org 0

Start:
     banksel GPIO
     clrf GPIO          ;clear GPIO
     movlw 07h
     movwf CMCON0       ;turn off comparators
     banksel TRISIO
     movlw b'00010000'  ;set pin3 as input rest as output
     movwf TRISIO
     banksel ANSEL
     movlw b'00011000'  ;set pin3 as analogue input (AN3)
     movwf ANSEL
     banksel ADCON0
     movlw b'00001101'  ;turn on ADC on AN3 left justified
     movwf ADCON0
     
Mainloop:
    nop                 ;wait for a bit
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    nop
    banksel ADCON0
    bsf ADCON0,GO       ;Do ADC
    btfsc ADCON0,GO
    goto $-1

    banksel ADRESH
    movf ADRESH,w
    movwf new           ;write upper 8 bits to new register
    swapf new,f         ;swap upper and lower bits
    rrf new,w           ;move 1 step to the right bits 5,6,7 now in positions 0,1,2
    andlw b'00000111'   ;clear 5 upper bits
    movwf new           ;write back to new register
    subwf current,w     ;subtract from current value
    skpz                ;skip next line if zero ie:- new = current
    goto counter        ;if new <> current goto counter
    movlw b'11111111'   ;reset count to 255
    movwf count
    goto Mainloop       ;back to the start

counter:
    decfsz count,f      ;deduct 1 from count, if count = 0 skip the next line
    goto Mainloop       ;if count > 0 go back to the start
    movf new,w          ;if count = 0 move value of new to current
    movwf current
    banksel GPIO
    movwf GPIO          ;and send to GPIO
    goto Mainloop       ;back to the start

    end

and i have etched a SOIC adapter with the pickit2 hooked up, and i've installed the MPLAB software, it seems to read the PIC fine.  but i have no idea how to compile the hex aside from copying the code into an MPLAB project source folder and hitting 'compile' which.. doesn't work.  i don't know if i need to set up the PIC differently first, or am missing some configuration type files, or have the wrong language, or location.

anyone got any advice as to programming these things?  i've been kinda slamming my head into various online resources but i lack the knowledge to know where i'm even going wrong and it's pretty overwhelming.  my programming knowledge extends to messing around with an arduino briefly.  i've been interested in the relay bypass threads and checked out coda effects' great write up but can't seem to apply to this PIC.

i would post in the DIYstompboxes thread but it's already a million pages long and would rather work it out first then post the answer there for any foragers.

many thanks for any assistance!  any pointers at all appreciated, my next bet is to start from scratch learning to program some simple LED blink type code onto the PIC to see how it works and then try and sorta reverse engineer the pot conversion code from there.
« Last Edit: December 03, 2017, 10:08:24 PM by oip »

Andlord

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Re: PIC programming super noob
« Reply #1 on: December 09, 2017, 07:19:51 AM »
.hex are already compiled. You only need to burn it in.
If you only have assambler code, that you need to compile I'd check youtube for a proper tutoriel:
https://www.youtube.com/results?search_query=pic+compile+assambler

Andlord

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Re: PIC programming super noob
« Reply #2 on: December 09, 2017, 07:22:08 AM »
If you want to get into designing your own uC applications I would highly recommend learning C not assambler. For most hobby projects it really makes not difference and C is so much easier to get into.

oip

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Re: PIC programming super noob
« Reply #3 on: December 09, 2017, 07:32:33 PM »
many thanks - yeah the more i think about it, it's probably best to try and program it myself from scratch by learning C.  the actual logic of the code seems pretty straightforward and it would be good to learn anyway in the long run, just a lot more work than i need to make a switch right now but oh well.  will check out some tutorials.