;_______________________________________________
; CRC8 computing functions
; Polynome 	x^8 + x^5 + x^4 + x^0 			->8C 	CRC-8-Dallas/Maxim
;   		x^8 + x^7 + x^4 + x^3 + x + 1 	->D9	CRC-8-WCDMA 
;_______________________________________________


;_______________________________________________
; Code segment
;_______________________________________________
;.cseg
;Sortie  R20 crc
;Entrée  R18 DATA
;Compeur R17 Count
;Général R16 A
;		 R19 temp
;_______________________________________________
; Update crc value
;_______________________________________________
CRC8Update:
  push A
  push count
  push DATA
  push temp
  ldi temp, 0x8C
  ldi count, 8	;pour boucle 8 bits
CRC8L:
  mov A,DATA	;ODD=DATA
  eor A,crc		;ODD=ODD^CRC
  lsr crc		;CRC>>1
  lsr DATA		;DATA>>1
  sbrc A, 0		;Saute si bit0 de ODD=0
  eor crc, temp	;CRC^0x8C
  
  dec count		;dec pour boucle	
  brne CRC8L	;continue la boucle si count<0
  pop temp
  pop DATA
  pop count
  pop A
  ret
;_______________________________________________
; Clear crc value
;_______________________________________________
CRC8Init:
  ldi crc ,0
  ret
;_______________________________________________
; Copy crc value to DATA
;_______________________________________________
GetCRC8:
  mov DATA,crc
  ret
;_______________________________________________
; End of crc8.inc file
;_______________________________________________