NEC PD750008 User Manual
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µPD750008 USER'S MANUAL
(2) SBI definition
The format of serial data and signal used in the SBI mode are described below.
Serial data to be transferred in the SBI mode is classified into three types: Address, command, and data.
Serial data forms one frame as shown below.
Figure 5-51 is a timing chart for transferring address, command, and data.
Figure 5-51. Timing of SBI Transfer
The bus release signal and command signal are output by the master. BUSY is output by a slave. ACK
is output by either the master or a slave. (Normally, the device which received 8-bit data outputs ACK.)
The master continues to output the serial clock from when 8-bit data transfer starts to when BUSY is
released.
SCK
A7
SB0, SB1
BUSY
8
9
A0
ACK
C7
SB0, SB1
READY
9
C0 ACK
BUSY
SB0, SB1
8
9
D7
READY
D0 ACK
BUSY
Address transfer
Bus release signal
Command transfer
Command signal
Data transfer
SCK
SCK