Cirrus Logic AN74 - Manual (Page 12)

AN74
12 AN74Rev2
;****************************************************************
;* Routine - TOGGLE_SDO
;* Input
- none
;* Output - none
;* Description -
This routine reset the DRDY pin by toggling
;* SCLK 8 times after SDO falls.
; This routine polls SDO, waits for it to be asserted, then clears SDO
; for next conversion by pulsing SCLK eight times after SDO falls
; This functions prototype in C is: void toggle_sdo(void);
;****************************************************************
$DEBUG
USING 0
; Use register bank 0
TCOD SEGMENT CODE ; Define Rout as a segment of code
PUBLIC TOGGLE_SDO ; Make subroutine public
RSEG TCOD ; Make code relocatable
TOGGLE_SDO:
MOV R1,#08 ; Setup counter
CLR P1.1 ; Clear SDI
JB P1.2,$ ; Poll SDO
loop:
SETB P1.3 ; Set SCLK
CLR P1.3 ; Clear SCLK
DJNZ R1,loop ; Decrement byte, repeat loop if not zero
RET ; Exit Subroutine
END