Rainbow-electronics ATmega163L Bedienungsanleitung PDF herunterladen (Seite 77)

ATmega163(L)

rjmp wait1

in r16, TWSR ; Check value of TWI Status Register.

cpi r16, START ; If status different from START go to ERROR

brne ERROR

ldi r16, 0xc8 ; Load SLA+W into TWDR register

out TWDR, r16

ldi r16, (1<<TWINT) | (1<<TWEN)

out TWCR, r16 ; Clear TWINT bit in TWCR to start transmission of address

wait2: in r16, TWCR ; Wait for TWINT flag set. This indicates that

sbrs r16, TWINT ; SLA+W has been transmitted, and ACK/NACK has

rjmp wait2 ; been received

in r16, TWSR ; Check value of TWI Status Register. If status

cpi r16, MT_SLA_ACK ; different from MT_SLA_ACK, go to ERROR

brne ERROR

ldi r16, 0x33 ; Load data (here, data = 0x33) into TWDR register

out TWDR, r16

ldi r16, (1<<TWINT) | (1<<TWEN)

out TWCR, r16 ; Clear TWINT bit in TWCR to start transmission of data

wait3: in r16, TWCR ; Wait for TWINT flag set. This indicates that

sbrs r16, TWINT ; data has been transmitted, and ACK/NACK has

rjmp wait3 ; been received

in r16, TWSR ; Check value of TWI Status Register. If status

cpi r16, MT_DATA_ACK ; different from MT_DATA_ACK, go to ERROR

brne ERROR

ldi r16, 0x44 ; Load data (here, data = 0x44) into TWDR register

out TWDR, r16

ldi r16, (1<<TWINT) | (1<<TWEN)

out TWCR, r16 ; Clear TWINT bit in TWCR to start transmission of data

;<send more data bytes if needed>

wait4: in r16, TWCR ; Wait for TWINT flag set. This indicates that

sbrs r16, TWINT ; data has been transmitted, and ACK/NACK has

rjmp wait4 ; been received

in r16, TWSR ; Check value of TWI Status Register. If status

cpi r16, MT_DATA_ACK ; different from MT_DATA_ACK, go to ERROR

brne ERROR

ldi r16, (1<<TWINT) | (1<<TWSTO) | (1<<TWEN)

out TWCR, r16 ; Transmit STOP condition

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Rainbow-electronics ATmega163L Bedienungsanleitung Seite 77