NEC PD75402A User Manual
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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
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.
[When output in synchronization with 11th SCK clock cycke]
SCK
SCK
SB0
SB0
[When output in synchronization with 9th SCK clock cycke]
ACK
ACK
8
9
10
11
8
9