+ Reply to Thread
Results 1 to 6 of 6
  1. #1
    Join Date
    Apr 2014
    Location
    Northeast
    Posts
    203

    Default Some ASM Help Please

    I am trying to use an all new PIC16F18426 for a personal project. I built a bench power supply, but the resolution on the LCD readout for Volts & Amps needed more resolution. The PIC16F18426 offers 12-bit ADC. However, since PBP3 cannot yet work with this new PIC, I'm trying my hand at ASM with MPLABX.


    The challenge I'm facing in the software is converting the ADC values to decimal and isolating the digits to print to the LCD. The Basic code works like a charm on a PIC16F1824:


    Code:
    Get_Ch1:                                    ;Get Channel 1 Values
        ADCON0 = 000011                      ;AN0, Volt1
        DO
            LOOP WHILE ADCON0.1 = 1
        V1.HIGHBYTE = ADRESH
        V1.LOWBYTE = ADRESL
        ADCON0 = 000111                      ;AN1, Amp1
        DO
            LOOP WHILE ADCON0.1 = 1
        A1.HIGHBYTE = ADRESH
        A1.LOWBYTE = ADRESL
        IF (V1 = V1p) AND (A1 = A1p) THEN
    RETURN
        ENDIF
        Volt1 = ((V1 + V1p) * 10) / 53
        GOSUB Print_V1
        V1p = V1
        IF (A1 + A1p) > (V1 + V1p) THEN
            Amp1 = (A1 + A1p) - (V1 + V1p)
        ELSE
            Amp1 = 0
        ENDIF
        GOSUB Print_A1
        A1p = A1
    RETURN
    
    
    Print_A1:                                   ;Amp1 Changed, Send to LCD, Line 2
        RS = 0
        LCD = $C0
        GOSUB Send
        RS = 1
        pause 1 
        for b0 = 0 to 7
            lookup b0, ["1-Amps: "], b1
            LCD = b1
            gosub Send
        next b0
        ARRAYWRITE Amp1a, [#Amp1]
        IF Amp1 < 100 THEN
            Amp1a[2] = Amp1a[1]
            Amp1a[1] = Amp1a[0]
            Amp1a[0] = " "
        ENDIF
        IF Amp1 < 10 THEN
            Amp1a[2] = Amp1a[1]
            Amp1a[1] = " "
            Amp1a[0] = " "
        ENDIF
        FOR b0 = 0 TO 2
            LCD = Amp1a[b0]
            GOSUB Send
        NEXT b0
        FOR b0 = 0 TO 3
            LOOKUP b0, [" mA "], b1
            LCD = b1
            GOSUB Send
        NEXT b0
    RETURN

    The Assembly Code generated for Print_A1 is as follows:


    Code:
    Print_A1:                                       ;Amp1 Changed, Send to LCD, Line 2
        LABEL?L    _Print_A1    
        MOVE?CT    000h, _RS            ;RS = 0
        MOVE?CB    0C0h, _LCD            ;LCD = $C0
        GOSUB?L    _Send                ;GOSUB Send
        MOVE?CT    001h, _RS            ;RS = 1
        PAUSE?C    001h                ;pause 1
        MOVE?CB    000h, _b0            ;for b0 = 0 to 7
        LABEL?L    L00031    
        CMPGT?BCL    _b0, 007h, L00032
        LOOKUP?BCLB    _b0, 008h, L00001, _b1    ;lookup b0, ["1-Amps: "], b1
        LURET?C    031h
        LURET?C    02Dh
        LURET?C    041h
        LURET?C    06Dh
        LURET?C    070h
        LURET?C    073h
        LURET?C    03Ah
        LURET?C    020h
    
    
        LABEL?L    L00001    
        MOVE?BB    _b1, _LCD            ;LCD = b1
        GOSUB?L    _Send                ;gosub Send
        NEXT?BCL    _b0, 001h, L00031    ;next b0
        LABEL?L    L00032
        ARRAYWRITENAME?B    _Amp1a        ;ARRAYWRITE Amp1a, [#Amp1]
        ARRAYWRITECOUNT?C    000h
        ARRAYWRITENUM?W    _Amp1
        ARRAYWRITEDEC?    
        CMPGE?WCL    _Amp1, 064h, L00033    ;IF Amp1 < 100 THEN
        MOVE?BB    _Amp1a + 00001h, _Amp1a + 00002h ;Amp1a[2] = Amp1a[1]
        MOVE?BB    _Amp1a, _Amp1a + 00001h        ;Amp1a[1] = Amp1a[0]
        MOVE?CB    020h, _Amp1a            ;Amp1a[0] = " "
        LABEL?L    L00033                ;ENDIF    
        CMPGE?WCL    _Amp1, 00Ah, L00035    ;IF Amp1 < 10 THEN
        MOVE?BB    _Amp1a + 00001h, _Amp1a + 00002h Amp1a[2] = Amp1a[1]
        MOVE?CB    020h, _Amp1a + 00001h        ;Amp1a[1] = " "
        MOVE?CB    020h, _Amp1a            ;Amp1a[0] = " "
        LABEL?L    L00035                ;ENDIF    
        MOVE?CB    000h, _b0            ;FOR b0 = 0 TO 2
        LABEL?L    L00037    
        CMPGT?BCL    _b0, 002h, L00038
        AOUT?BBB    _Amp1a, _b0, _LCD    ;LCD = Amp1a[b0]
        GOSUB?L    _Send                ;GOSUB Send
        NEXT?BCL    _b0, 001h, L00037    ;NEXT b0
        LABEL?L    L00038                ;FOR b0 = 0 TO 3    
        MOVE?CB    000h, _b0
        LABEL?L    L00039    
        CMPGT?BCL    _b0, 003h, L00040
        LOOKUP?BCLB    _b0, 004h, L00002, _b1    ;LOOKUP b0, [" mA "], b1
        LURET?C    020h
        LURET?C    06Dh
        LURET?C    041h
        LURET?C    020h
    
    
        LABEL?L    L00002
        MOVE?BB    _b1, _LCD            ;LCD = b1
        GOSUB?L    _Send                ;GOSUB Send
        NEXT?BCL    _b0, 001h, L00039    ;NEXT b0
        LABEL?L    L00040    
        RETURN?                    ;RETURN

    I tried copy/pasting the above code into MPLABX & pretty much all of it generated errors. I've tried numerous approaches but none have worked. Any ideas how to isolate decimal digits (1000s, 100s, 10s, 1s) from a larger value?

  2. #2
    Join Date
    Apr 2014
    Location
    Northeast
    Posts
    203

    Default Re: Some ASM Help Please

    Oh, the PIC16F18426 uses the mid-range instruction set, so there are no DAW or CMPFSEQ type commands.

  3. #3
    Join Date
    Sep 2009
    Posts
    637

    Default Re: Some ASM Help Please

    That isn't ASM instruction. It is ASM macro, from PBP library.
    Alos arraywrite, etc... All instruction with ? are from PBP lib's.

  4. #4
    Join Date
    Apr 2014
    Location
    Northeast
    Posts
    203

    Default Re: Some ASM Help Please

    Something to go on.

  5. #5
    Join Date
    Sep 2009
    Posts
    637

    Default Re: Some ASM Help Please

    You must dig little dipper in PBP librarys. Look for PBPPICxx.mac and PBPPICxx.LIB files for macro definition.
    If I was in your place, I would start from controlling PIN, then LCD basic communication, to display char, then to math involved in digit extraction...
    EDIT:
    PBP libs are great resource for learning ASM.... Lot of work and testing are organized and described in one place....
    I learned ASM from PBP lib, and PIC datasheet. Now all interrupts my are written in ASM.
    Last edited by pedja089; - 13th May 2018 at 18:43.

  6. #6
    Join Date
    Apr 2014
    Location
    Northeast
    Posts
    203

    Default Re: Some ASM Help Please

    Thanks, predja089. Spent the day fighting with it, but I have something that works. I tried typing it into PBP3 & looking at the ASM, but that didn't get me there. Now I'm able to take an ADC-12 read (0 >> 4095) and convert it into 4 decimal digits:

    Code:
    	MOVF	ADRESH,W
    	MOVWF	b0
    	MOVF	ADRESL,W
    	MOVF	b1
    	CALL	DoMath
    	MOVLW	0x30
    	ADDWF	Dig1,W
    	MOVWF	Volts11
    	MOVLW	0x30
    	ADDWF	Dig2,W
    	MOVWF	Volts12
    	MOVLW	0x30
    	ADDWF	Dig3,W
    	MOVWF	Volts13
    	MOVLW	0x30
    	ADDWF	Dig4,W
    	MOVWF	Volts14
    	CALL	Display
    	RETURN
    
    DoMath:
        BANKSEL Dig1
        CLRF    Dig1
        CLRF    Dig2
        CLRF    Dig3
        CLRF    Dig4
        BCF	    STATUS, C
        BCF	    STATUS, DC
    Math2:			    ;Find the 1000,s Digit
        MOVLW   0x03
        SUBWF   b1, W
        BTFSS   STATUS,C
        BRA	    Math3
        MOVLW   0xE8
        SUBWF   b0, W
        BTFSS   STATUS,C
        BRA	    Math2a
        MOVLW   0x03
        SUBWF   b1, F
        MOVLW   0xE8
        SUBWF   b0, F
        INCF    Dig1
        BRA	    Math2
    Math2a:
        MOVLW   0x04
        SUBWF   b1,W
        BTFSS   STATUS,C
        GOTO    Math3
        MOVLW   0x04
        SUBWF   b1,F
        MOVLW   0x18
        ADDWF   b0
        INCF    Dig1
        BRA	    Math2
    Math3:			    ;Find the 100,s Digit
        MOVLW   0x64
        SUBWF   b0, W
        BTFSS   STATUS,C
        BRA	    Math4
        MOVLW   0x64
        SUBWF   b0, F
        INCF    Dig2
        BRA	    Math3
    Math4:			    ;Account for V1H Carry/Borrow
        DECF    b1, W
        BTFSS   STATUS,Z
        GOTO    Math5
        DECF    b1,F
        MOVLW   0x9C
        ADDWF   b0
        INCF    Dig2
        BRA	    Math3
    Math5:			    ;Find the 10,s Digit
        MOVLW   0x0A
        SUBWF   b0, W
        BTFSS   STATUS,C
        BRA	    Math6
        MOVLW   0x0A
        SUBWF   b0, F
        INCF    Dig3
        BRA	    Math5
    Math6:
        MOVF    b0,W
        MOVWF   Dig4
     RETURN

Similar Threads

  1. ASM help
    By Charles Linquis in forum mel PIC BASIC Pro
    Replies: 16
    Last Post: - 21st October 2009, 03:08
  2. ASM or PBP First?
    By mackrackit in forum Off Topic
    Replies: 4
    Last Post: - 10th October 2009, 12:08
  3. ASM Help
    By fbraun in forum mel PIC BASIC Pro
    Replies: 2
    Last Post: - 11th October 2007, 16:05
  4. How to do this in ASM?
    By Kamikaze47 in forum mel PIC BASIC Pro
    Replies: 10
    Last Post: - 19th November 2005, 07:38
  5. asm to picbasic
    By wilfried in forum mel PIC BASIC Pro
    Replies: 1
    Last Post: - 12th March 2003, 01:18

Members who have read this thread : 13

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts