Maxim Integrated MAXQ Family Users Guide: MAXQ8913 Supplement - Manual (Page 95)

MAXQ Family User’s Guide:
MAXQ8913 Supplement
22-9
22.2.4 I 2 C Example 4: Slave Mode Receive
; I2C configured as slave with address 1ah
; Setup for Slave Mode Receive
move I2CSLA, #01ah
; I2C Slave Address = 01ah
move I2CCN, #0001h ; I2CEN = 1, I2CMST = 0, I2CMODE = 0, I2CSTART = 0
call wait_start ; Polling routine to wait for I2CSTART to be set,
; indicating a received START
;; Check for address match
move ACC, I2CST
and #0020h ; Check for Address Match flag set
cmp #0020h
jump ne, no_match ; Not an address match
move ACC, I2CCN ; Check transfer mode is set
and #004h
cmp #004h
jump ne, not_sl_xmit ; If transfer mode is low, not a slave transmit, else:
move I2CBUF, #0aah ; Data byte to be transmitted
call wait_xmit ; Poll for transmit done
;; Verify ACK received from master
move ACC, I2CST
and #080h
cmp #000h
jump ne, FAIL ; If NACK bit set, handle retransmission, else continue
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