NEC PD75402A User Manual
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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
(f)
Busy signal (BUSY), ready signal (READY)
The busy signal notifies the master that a slave is preparing for data transmission/reception.
The ready signal notifies the master that a slave is ready for data transmission/reception.
Fig. 5-41 Busy Signal & Ready Signal
With the SBI a slave reports its busy status to the master by driving the SB0 line low.
The busy signal is output following the acknowledge signal output by the master or slave. Busy signal
setting/release is performed in synchronization with the fall of SCK. When the busy signal is released the
master automatically terminates output of the SCK serial clock.
When the busy signal is released and the ready signal sate is entered the master can start the next transfer.
SCK
SB0
ACK
BUSY
READY
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