; ;******************************************************************** ; Binary To BCD Conversion Routine ; This routine converts a 16 Bit binary Number to a 5 Digit ; BCD Number. This routine is useful since PIC16C55 & PIC16C57 ; have two 8 bit ports and one 4 bit port ( total of 5 BCD digits) ; ; The 16 bit binary number is input in locations H_byte and ; L_byte with the high byte in H_byte. ; The 5 digit BCD number is returned in R0, R1 and R2 with R0 ; containing the MSD in its right most nibble. ; ; Performance : ; Program Memory : 35 ; Clock Cycles : 885 ; ; ; Program: B16TOBCD.ASM ; Revision Date: ; 1-13-97 Compatibility with MPASMWIN 1.40 ; ;*******************************************************************; ; ; include "p16f887.inc" ; global B2_BCD, H_byte, L_byte, R0, R1, R2 udata count res 1 temp res 1 ; H_byte res 1 L_byte res 1 R0 res 1 ; RAM Assignments R1 res 1 R2 res 1 B16TOBCD code B2_BCD bcf STATUS,0 ; clear the carry bit movlw .16 movwf count clrf R0 clrf R1 clrf R2 loop16 rlf L_byte, F rlf H_byte, F rlf R2, F rlf R1, F rlf R0, F ; decfsz count, F goto adjDEC RETLW 0 ; adjDEC movlw R2 movwf FSR call adjBCD ; movlw R1 movwf FSR call adjBCD ; movlw R0 movwf FSR call adjBCD ; goto loop16 ; adjBCD movlw 3 addwf 0,W movwf temp btfsc temp,3 ; test if result > 7 movwf 0 movlw 30 addwf 0,W movwf temp btfsc temp,7 ; test if result > 7 movwf 0 ; save as MSD RETLW 0 END