CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS

(e) Acknowledge signal (ACK)

The acknowledge signal is used to confirm serial data reception between the sender and receiver.

Fig. 5-40 Acknowledge Signal

[When output in synchronization with 11th SCK clock cycke]

SCK

8

9

10

11

SB0

 

 

 

ACK

[When output in synchronization with 9th SCK clock cycke]

SCK

8

9

SB0

 

ACK

The acknowledge signal is a one-shot pulse synchronized with the fall of SCK after an 8-bit data transfer. Its position is arbitrary and it can be synchronized with any SCK clock cycle.

After 8-bit data transmission the sender checks whether the receiver has sent back an acknowledge signal. If an acknowledge signal is not returned within a specific time after data transmission, reception can be judged not to have been performed correctly.

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NEC PD75P402, PD75402A user manual Acknowledge signal ACK, SCK SB0 ACK