Atmega163(l) – Rainbow Electronics ATmega163L User Manual
Page 80
ATmega163(L)
80
wait6:
in
r16,TWCR
; Wait for TWINT flag set. This indicates that
sbrs
r16, TWINT
; SLA+R has been transmitted, and ACK/NACK has
rjmp
wait6
; been received
in
r16, TWSR
; Check value of TWI Status Register. If status
cpi
r16, MR_SLA_ACK
; different from MR_SLA_ACK, go to ERROR
brne
ERROR
ldi
r16, (1< out TWCR, r16 ; Clear TWINT bit in TWCR to start reception of data. ; Setting TWEA causes ACK to be ; returned after reception of data byte wait7: in r16,TWCR ; Wait for TWINT flag set. This indicates that sbrs r16, TWINT ; data has been received and ACK returned rjmp wait7 in r16, TWSR ; Check value of TWI Status Register. If status cpi r16, MR_DATA_ACK ; different from MR_DATA_ACK, go to ERROR brne ERROR in r16, TWDR ; Input received data from TWDR. nop ; ldi r16, (1< out TWCR, r16 ; Clear TWINT bit in TWCR to start reception ; of data. Setting TWEA causes ACK to be ; returned after reception of data byte ; ;receive next to last data byte. wait8: in r16,TWCR ; Wait for TWINT flag set. This indicates that sbrs r16, TWINT ; data has been received and ACK returned rjmp wait8 in r16, TWSR ; Check value of TWI Status Register. If status cpi r16, MR_DATA_ACK ; different from MR_DATA_ACK, go to ERROR brne ERROR in r16, TWDR ; Input received data from TWDR. nop ; ldi r16, (1< out TWCR, r16 ; Clear TWINT bit in TWCR to start reception of data. ; Not setting TWEA causes NACK to be ; returned after reception of next data byte ; receive last data byte. Signal this to slave by returning NACK wait9: in r16,TWCR ; Wait for TWINT flag set. This indicates that sbrs r16, TWINT ; data has been received and NACK returned rjmp wait9 in r16, TWSR ; Check value of TWI Status Register. If status cpi r16, MR_DATA_NACK ; different from MR_DATA_NACK, go to ERROR