please dont rip this site

PIC Microcontoller Radix Math Method


Binary to ASCII, 16 bit to 5 digits with leading zero suppression and fixed decimal point

from Dontronics and Scott Edwards

Also: PIC Microcontoller Radix Math Methods

; BIN_ASC 16-bit value
; This routine converts a 16-bit number into a counted string of
; ASCII characters compatible with Serout. It suppresses
; leading zeros so that numbers like 17 are sent as "17" not "00017".

buffer = 31 ; String buffer at end of memory.
ASC_0 = '0'     ; ASCII numbers: 30h thru 39h.
ASC_dp = '.'     ; ASCII char for decimal point (period).
fix = 3 ; Position for fixed decimal point.

 org 8
dec_no Res 1 ; Decade (1,10,100...) to work on.
tempH Res 1 ; 16-bit temporary variable used by
tempL Res 1 ; the BIN_ASC routine.
hiB Res 1 ; MSB of number to convert.
lowB Res 1 ; LSB of number to convert.
flags ds 1
zs = flags.0 ; Leading-zero suppression flag.

             P = pic16c55
;  device pic16c55,xt_osc,wdt_off,protect_off
 reset start
 org 0

; Table consisting of values 10,000, 1000, 100, 10, and 1.

decade      ADDWF 02, _W
             RETLW 39
             RETLW 16
             RETLW 3
             RETLW 232
             RETLW 0
             RETLW 100
             RETLW 0
             RETLW 10
             RETLW 0
             RETLW 1

start        MOVLW $FF			; To see routines output, either
             MOVWF hiB
             MOVLW $FF			; use the PSIM PIC simulator, or
             MOVWF lowB
             CALL BIN_ASC		; merge with Serout.
             GOTO $			; Endless loop

; This routine accepts a 16-bit number in hiB, lowB and converts it into
; a counted ASCII text string located at the address "buffer." The buffer
; grows downward in memory. The first (0th) item in buffer is the number
; of characters in the string. The routine destroys the contents of
; hiB, lowB. If this value is required elsewhere, make a copy.

BIN_ASC      CLRF buffer		; Clear char count (item 0 in buf).
             CLRF flags			; Clear zs flag.
             CLRF dec_no		; Clear decade no.
             MOVLW buffer-1		; Reserve 0th byte of buffer for count.
             MOVWF fsr
BIN_ASC_loop
             MOVF dec_no ,_w
             CALL decade		; from the lookup table.
             MOVWF tempH
             INCF dec_no ,F		; Get 2nd digit of decade no.
             MOVF dec_no ,_w
             CALL decade                
             MOVWF tempL
             CALL d_point		; Insert decimal point.
             CALL sub_it		; Divide hiB,lowB by tempH,tempL
             MOVF indirect ,_w
             BTFSC flags, 0		; If zs = 0 AND digit = 0 then
             GOTO BIN_ASC_no_zs
             BTFSC 3,2			; digit is a leading zero to be
             GOTO BIN_ASC_no_zed
BIN_ASC_no_zs
             MOVWF indirect
             ADD indirect,#ASC_0 	; an included zero (as in 7501)
             INCF buffer, F		; or a non-zero digit.
             DECF fsr, F		; Point to next memory location.
             BSF flags, 0		; First non-zero digit sets zs bit.
BIN_ASC_no_zed
             INCF dec_no,F		; Next decade.
             MOVLW 8			; If dec_no = 8, we're down to ones.
             SUBWF dec_no ,_w
             BTFSS 3,2
             GOTO BIN_ASC		; Otherwise, do next decade.
             INCF dec_no ,F		; Update decade number for d_point.
             CALL d_point		; Decimal point here?
             MOVF lowB ,_w
             MOVWF indirect
             ADD indirect,#ASC_0 	; Add offset for conversion to ASCII.
             INCF buffer, F		; Add 1 to character count.
             RETLW 0h                   

; This routine performs division by iterated subtraction. It is efficient
; in this application because the dividend and divisor keep getting smaller
; as BIN_ASC runs, so the quotient is never larger than nine. A general-
; purpose division routine would be slower (and longer).

sub_it       CLRF indirect		; Clear to track no. of subtractions.
sub_it_loop  MOVF tempL,_w		; Subtract LSB.
             SUBWF lowB, F
             BTFSC 3,0			; If no borrow, continue w/MSB.
             GOTO sub_it_skip
             MOVLW 1			; Otherwise borrow from MSB.
             SUBWF hiB, F
             BTFSC 3,0			; If borrow causes a carry, then
             GOTO sub_it_skip
             INCF hiB, F		; add numbers back and return.
             MOVF tempL,_w               
             ADDWF lowB, F
             RETLW 0h                   
sub_it_skip  MOVF tempH,_w		; Subtract MSB.
             SUBWF hiB, F
             BTFSC 3,0			; If no borrow, subtract again.
             GOTO sub_it_skip2
             ADD lowB,tempL		; Otherwise, undo the subtraction
             BTFSC 3,0			; by adding entire 16-bit no.
             INCF hiB, F		; back together and return.
             ADD hiB,tempH
             RETLW 0                   
sub_it_skip2 INCF indirect, F		; No borrow, so do it again.
             GOTO sub_it_loop

; This routine adds a decimal point in the location set by "fix" in the
; equates at the beginning of the program. The location of the decimal point
; is in front of the "fix"ed digit, numbered starting with 0. If you fix the
; point at 0, the first (0th) character in the string produced by BIN_ASC
; will be a decimal point. If you don't want a decimal point, either move
; it out of range (fix = 6), or delete this routine and the "call d_point"
; in the body of BIN_ASC above.

d_point      MOVLW fix*2+1              
             SUBWF dec_no ,_w
             BTFSS 3,2
             RETLW 0h                   
             BSF flags, 0
             MOVLW ASC_dp               
             MOVWF indirect
             INCF buffer, F
             DECF fsr, F
             RETLW 0h

Questions:

Comments:

See also:


file: /Techref/microchip/math/radix/b2a-16b5dlzd.htm, 12KB, , updated: 2009/11/23 16:43, local time: 2014/8/28 22:28, owner: JMN-EFP-786,
TOP NEW HELP FIND: 
54.205.99.71:LOG IN

 ©2014 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE! / 

<A HREF="http://www.piclist.com/techref/microchip/math/radix/b2a-16b5dlzd.htm"> PIC Microcontoller Radix Math Method Binary to ASCII, 16 bit to 5 digits </A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

  PICList 2014 contributors:
o List host: MIT, Site host massmind.org, Top posters @20140828 RussellMc, Richard R. Pope, IVP, John Gardner, alan.b.pearce, David C Brown, James Cameron, Josh Koffman, Bob Blick, Isaac Marino Bavaresco,
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
 

Welcome to www.piclist.com!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .