Cirrus-logic AN88 Manuel d'utilisateur télécharger pdf (Page 10)

AN88

10 AN88Rev2

;*************************************************************************************

;* Routine - write_register

;* Input - COMMANDBYTE, HIGHBYTE, MIDBYTE, LOWBYTE

;* Output - none

;* This subroutine instructs the CS5525/6/9 to write to an internal register.

;*************************************************************************************

write_register BCF PORTA,CS ; Clear Chip Select

MOVF COMMANDBYTE,0 ; Load W with COMMANDBYTE

CALL send_spi ; transfer byte

MOVF HIGHBYTE,0 ; Load W with HIGHBYTE

CALL send_spi ; transfer byte

MOVF MIDBYTE,0 ; Load W with MIDBYTE

CALL send_spi ; transfer byte

MOVF LOWBYTE,0 ; Load W with LOWBYTE

CALL send_spi ; transfer byte

BSF PORTA,CS ; Set Chip Select

RETURN ; Exit Subroutine

;*************************************************************************************

;* Routine - read_register

;* Input - COMMANDBYTE

;* Output - HIGHBYTE, MIDBYTE, LOWBYTE

;* This subroutine reads an internal register of the ADC.

;*************************************************************************************

read_register BCF PORTA,CS ; Clear Chip Select

MOVF COMMANDBYTE,0 ; Load W with COMMANDBYTE

CALL send_spi ; transfer byte

CALL receive_spi ; receive byte

MOVWF HIGHBYTE ; Move W to HIGHBYTE

CALL receive_spi ; receive byte

MOVWF MIDBYTE ; Move W to MIDBYTE

CALL receive_spi ; receive byte

MOVWF LOWBYTE ; Move W to LOWBYTE

BSF PORTA,CS ; Set Chip Select

RETURN ; Exit Subroutine

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Cirrus-logic AN88 Manuel d'utilisateur Page 10