Cirrus-logic AN131 Manual de usuario descargar pdf (Pagina 9)

AN131

AN131REV2 9

; Setup 4 Settings - (A1-A0 = 00, Physical Channel = 3, OWR = 15Hz,

; input V-range = 25mV, Unipolar)

LDA #$4C ;Load ACCA with first byte of CSR #2

JSR send_spi ;Send byte number one

LDA #$01 ;Load ACCA with second byte of CSR #2

JSR send_spi ;Send byte number two

LDA #$05 ;Load ACCA with third byte of CSR #2

JSR send_spi ;Send byte number three

RTS ;Exit subroutine

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

;* Routine - calibrate

;* Input - none

;* Output - none

;* This subroutine instructs the CS5521/22/23/24/28 to perform a self-calibration on

;* Setup 1.

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

calibrate LDA #$81 ;Command for Self-Offset Cal, Setup 1

JSR send_spi ;Send Self-Cal command to ADC

poll_sdo1 BRSET 2,PORTD, poll_sdo1 ;Wait for SDO to fall

RTS ;Exit Routine

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

;* Routine - rwgain

;* Input - none

;* Output - contents of gain register on PC1 in HIGH, MID and LOW bytes

;* This subroutine first writes, and then reads back the value of the gain

;* register on Physical Channel 1

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

;*** Write to Gain Register of Physical Channel 1 ***

rwgain LDA #$02 ;Command to Write Gain Register of PC 1

STA COMMAND ;Prepeare COMMAND byte

LDA #$80 ;Value for High Byte

STA HIGHBYTE ;Prepare HIGHBYTE

CLR MIDBYTE ;Prepare MIDBYTE

CLR LOWBYTE ;Prepare LOWBYTE

JSR write_register;Write to Gain Register

;*** Read From Gain Register of Physical Channel 1 ***

LDA #$0A ;Command to Read Gain Register of PC 1

STA COMMAND ;Prepare COMMAND byte

JSR read_register;Read from Gain Register

RTS ;Return

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Cirrus-logic AN131 Manual de usuario Pagina 9