PIC Microcontoller Radix Conversion Math Methods

• ASCII
  • 1 digit Hex to Binary 4 bits From Regulus Berdin, Tracy Smith, Samuel Tardieu
  • 2 digit Hex to Binary 8 bits from Andrew Warren
  • 2 digit Hex to Binary 8 bits from Peter F. tsetsetse at hotmail.com
  • 2 digit Hex to Binary 8 bits from Paulswork
  • 2 digit Decimal to Binary 8 bits from Scott Dattalo and Dmitry Kiryashov
  • 3 digit Decimal to Binary 8 bits from Robert White
• BCD
  • packed to binary 2 digit to 8 bit from Scott Dattalo
  • Packed BCD to 16 bit binary conversion by Nikolai Golovchenko
  • half-packed to ASCII decimal 3 digit to 8 bit from Scott Dattalo
  • unpacked to binary 2 digit to 8 bit from Mike Keitz
  • Unpacked BCD to 16 bit binary conversion by Tony Kübek
  • Unpacked BCD to 16 bit binary conversion by Nikolai Golovchenko
  • 5 digit BCD unpacked to 16bit binary in 33 inst, 33 cycles by Peter Hemsley +
  • 10 digit BCD unpacked to 32bit binary by Brian Beard
  • RTC formats by Drew Vassallo
• Binary
  • to BCD
    • 4bit to BCD 2 digits from Bob Ammerman
    • 8bit to BCD half-packed (3 digits) from Scott Dattalo
    • 8bit to BCD half-packed (3 digits) by Mike McLaren, K8LH
    • 8bit to extract decimal 1's, 10's, 100's from jsvetlin
    • 10bit to BCD unpacked 3 digit in 25 inst 28 cycles by Djula Djarmati (for PIC's with hardware multiplier only)
    • 10bit to BCD unpacked 4 digit in 38 inst ~88 cycles by E. A. Grens with:
      12bit to BCD unpacked 4 digit in 35 inst ~118 cycles by Peter Hemsley +
    • 16bit to BCD unpacked 5 digit 50 inst, ~200 executed 5 output registers from John Payson
    • 16bit to BCD unpacked 5 digit 131 inst, isosyncronos from Juan Mayoral
    • 17bit to BCD unpacked 5 full digits from Mike Mansheim of Graco, Inc.
    • 24bit to BCD 8 digits by Oliver Broad
    • 24bit to BCD unpacked 8 digits (several versions) in as little as 25 inst or as few as 1242 cycles by Peter Hemsley, Steve Teal, Harry West, and Michael McLoughlin +
    • 32bit to BCD packed and ASCII 10 digits from Ron Kreymborg and Mike Keitz
    • 32bit to BCD unpacked 10 digits by Brian Beard
  • to ASCII
    • 4bit to ASCII HEX 1 digit fast from http://www.myke.com/basic.htm
    • 4bit to ASCII HEX 1 digits by Scott Dattalo and Sean H. Breheny
    • 4bit to ASCII HEX 1 digit indirect by Samuel Tardieu +
    • 8bit to ASCII HEX 2 digits by Scott Dattalo and Sean H. Breheny
    • 8Bit to ASCII HEX 2 digits from Paulswork
    • 7bit to ASCII decimal 3 digits by Bob Axtell +
    • 8bit to ASCII Decimal 3 digits from A. Borowski
    • 8bit to ASCII Decimal 3 digits from Daniel Serpell
    • 16bit to ASCII Decimal 5 digits with leading zero suppression and fixed decimal point from Dontronics and Scott Edwards
    • 16bit to ASCII Decimal 5 digits in 1 temp register, 76 instructions, ~500 executed by James Newton (Parallax menomics see Macros for using Parallax instructions with MPASM also Prlx.asm)
    • 16bit to ASCII Decimal 5 digits in 0 temp registers, 42 instructions, ~266 executed by Rich Leggit tweaked by Scott Dattalo.and bugfix by Dmitry Kiryashov and Nikolai Golovchenko
    • 16bit to ASCII Decimal 5 digits in 0 temp registers, 68 instructions, ~220 executed by Nikolai Golovchenko
    • 16bit to ASCII Decimal 3 digits (999) in 0 temp registers, 34 instructions, ~87 executed by Nikolai Golovchenko
    • 16bit to ASCII Decimal 3 digits (999) in 0 temp registers, 59 instructions, ~60 executed by Nikolai Golovchenko
    • 24bit signed to ASCII Decimal 8/9 digit decimal with point and minus sign (if negative) by Tony Kübek
    • 32bit to BCD packed and ASCII Decimal 10 digits from Ron Kreymborg and Mike Keitz

Also:

• C code for Base Conversion
• Convert ASCII to upper case
• Conditionally replaceing one value with another
• Borowski Hex Format
• The "Bill & Pookie" 10 bit A2D binary to decimal w/scaleing code generator

See also:

• http://www.shm.monash.edu.au/~r.kreymborg/pic/dopic.cgix?ascii16 This is a dead link
• http://www.shm.monash.edu.au/~r.kreymborg/code.html 16 or 32 bit binary to ASCII

Archive:

• PICList post "Brute force 16bit to BCD" +
• PICList post "fixed point to ASCII on 16F87x?" +
• PICList post "24Bit and 32 Bit Binary to ASCII conversion with DAW instruction, How?" Bob Ammerman's MPASM macro for ANY size of Binary to ASCII conversion. +
• PICList post "10 bit binary value to 4 char BCD." +
• PICList post "16 bit value" Converted to decimal milliVolts +
• PICList post "16bit divide by 10" +
• PICList post "CCS 'C' Code Help Req'"
• PICList post "Binary to Decimal output ???" ASM for CCS C compiler
• PICList post "24-bit binary to BCD?" conditional assembly of 16,24 or 32 bit conversion

Comments:

• Thank's a lot for such an useful site ! I got several routines there and all of them work perfectly well, saving hours of brain storming for me with probably not such so good results... Denis, from France+
• You are VERY welcome! Please do consider shareing any code you do end up writing

Questions:

• brianszczepanik~NOSPAM~ at KILLspamyahoo.ca asks: " im looking for a way to convert an eight digit decimal number to two 16 bit words using only 16 bit architecture" +
• szaroletta~NOSPAM~ at KILLspamhotmail.com asks: " I am looking for relocatable code, or a macro which converts a hex number like FE8A into the corresponding ASCII-Code."

  Convert the Hex digits to binary (16bits) and then convert the binary to ASCII.

  Apply one of the "2 digit Hex to Binary 8 bits" routines to the first two hex digits and then again to the second, thereby producing two 8 bit values that are then passed to any one of the "16bit to ASCII Decimal 5 digits" routines. +

Interested:

See:

Code:

• shares this code:

  ;some code snippets that someone might find useful...
  
  ;This routine will return the number of decimal 
  ;hundreds from an 8-bit binary
  ;Input: w
  ;Output: w
  ;RAM:2
  ;Cycles: 12-24
  
  GETHNDS		movwf	t1
                  clrf    w2
  gethnds_loop	movlw	.100
  		incf	w2,f
  		subwf	t1,f
  		btfsc	STATUS,C
  		goto 	gethnds_loop
  		decf	w2,w
  		return		
  ;---
  ;This routine will return the number of decimal 
  ;tens from an 8-bit binary
  ;Loop based, so it might take some time...
  ;It needs getones too
  GETTENS		movwf	t1
                  clrf    w2
  gettens_loop	movlw	.10
  		incf	w2,f
  		subwf	t1,f
  		btfsc	STATUS,C
  		goto 	gettens_loop
  		decf	w2,w
  		goto	getones
  
  ;---
  ;This routine will return the number of decimal 
  ;ones from an 8-bit binary	
  GETONES		movwf	w2
  		movlw	.10
  deltens_loop	subwf	w2,f
  		btfsc	STATUS,C
  		goto 	deltens_loop
  		addwf	w2,w	
  		return
  
  

  +

Code:

• Compact and fast 10bit to BCD conversion for converting 
  small / midrange PIC 10bit ADC ADRSH and ADRSL 	
   
  ;****************************************************
  ;*	10bit BINARY to BCD		*
  ;****************************************************
  ;
  ;An implimentation of the 'Shift and add-3' Algorithm
  ;		for small MicroChip 'PIC' microcomputers
  ;
  ;ALGORITHM
  ;
  ;1)Shift binary number one bit left (into a BCD 'result'
  ;  (initially empty)
  ;2)If any 4 bit BCD column is greater than 5[hex] add 3[hex]
  ;3)Goto 1) {until the LSB binary bit is shifted out}
  ;
  ;<------MSB				LSB-----&gt;
  ;------------- BCD ------------]  [------ binary -----
  ;					
  ;	   TENS		  UNITS
  ;	BCD column	BCD column	MSB	bit	bit	
  ;	0  0  0  0	0  0  0  0	 1	 0	 1	 
  ;
  ;				<------	/  <---/    <---/ 
  ;Inalisation
  ;**************
  
  Processor 16F818
  include <p16f818.inc>
  
  
  cblock	0x020	;Define variable block starting at $020
  
  binH		;bin is the 8bit binary value to be converted
  bin		;The 2bit binary MSB's to be converted
  bcdH		;Thousands (always blank)/ Hundreds nybbles
  bcdL		;Tens / Units nybbles
  counter
  temp
  	
  endc
  
  
  	
  
  _bin2bcd	  movlw    	d'8'
  
  	movwf   counter
  
          clrf    bcdL		
          clrf    bcdH
  			
  ;Save time by not shifting in first 6 bits  (always '0's)
  ;--------------------------------------------------------
  	swapf	binH,1	;Chop off first nybble (TEN THOUSANDS)
  	rlf	binH,1	;Shift out first 2 MSB's(always '0's)
  	rlf	binH,1
  
  ;Ssave more ime by no test and add +3' for first TWO shifts
  ;---------------------------------------------------------------------
  			
  	 rlf    binH,F	;Shifting 'binH' left through carry into BCD nybbles
           rlf    bcdL,F	
           rlf    binH,F
           rlf   	bcdL,F	;binH (pic ADC register ADRESH) done with!
  
             
  ;Iteration loop shifts the 4 'columns' (10TH, THO, HUN, TEN, UNT) 1 bit left
  ;Tests each coulmn (4bit nybble) if > 5, adds '3' 
  ;Shifts in the next MSB of the binary for conversion on the right. 
  ;(for remaining EIGHT shifts)
  
  Next_bit movfw   bcdL
           addlw   0x33	 ;Add 3 to both nybbles (T/U) in 'temp'
           movwf   temp
           movfw   bcdL
           btfsc   temp,3  ;Test MSB of Units+3 nybble in 'temp 
           addlw   0x03	  ;Add 3 to U nybble if units+3 MSB = 1 
           btfsc   temp,7  ;Test MSB of Tens+3nybble in 'temp'
           addlw   0x30	 ;Add 3 to T nybbleiftens+3 MSB=1 (>5)	
           movwf   bcdL
  		
  	 movfw	 bcdH
  	 addlw	 0x33	 ;Add 3 to both nybbles (T/H) in temp
  	 mmovfw	 bcdH
  	 btfsc   temp,3  ;Test MSB of Hundreds+3 nybble in temp 
           addlw   0x03	  ;Add 3 to H nybble if units+3 MSB=1
           btfsc   temp,7  ;Test MSB of Thousand+3 nybble in temp
           addlw   0x30	 ;Add 3 to TH nybble if tens+3 MSB=1
  	 movwf	 bcdH
  
   	 rlf     bin,F	 ;Shift in next MSB from bin into T/UNITS
    	 rlf	 bcdL,F  ;Shift next MSB from TENS/UNITS to TH/H
           rlf     bcdH,F  ;Shift up 
  
           decfsz  counter,F
           goto    Next_bit
           return
  
  
  
  end
  

  +

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