7220 Datasheet, PDF (206/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
5.5 Example of I²C-BUS control by software (M37220M3-XXXSP/FP)
(8) Return ACK processing routine
Return ACK
Bit 0 of port P2 direction register
= “output mode”
P20 (SDA) = “0”
Wait 6 µs
P21 (SCL) = “1”
Wait 6 µs
P21 (SCL) = “0”
RETURN
Fig. 5.5.11 Flowchart of return ACK processing routine
(9) Return NACK processing routine
Return NACK
Bit 0 of port P2 direction register
= “output mode”
P20 (SDA) = “1”
Wait 6 µs
P21 (SCL) = “1”
Wait 6 µs
P21 (SCL) = “0”
RETURN
Fig. 5.5.12 Flowchart of return NACK processing routine
7220 Group User’s Manual
5-33