CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS

(2) SBI definition

The SBI serial data format and the meaning of the signals used are explained in the following section. Serial data transmitted via the SBI is classified into three types: Commands, addresses and data. Serial data forms a frame with the configuration shown below.

Address, command and data transfer timing is shown in Fig. 5-33.

Fig. 5-33 SBI Transfer Timing

Address Transfer

SCK8 9

SB0

A7

A0

ACK

BUSY

Bus Release

Signal

Command Transfer

Command Signal

SCK9

SB0

C7

C0 ACK

BUSY

READY

Data Transfer

SCK8 9

SB0

D7

D0 ACK

BUSY

READY

The bus release signal and command signal are output by the master. The BUSY signal is output by the slave. ACK can be output by either the master or slave (normally output by the 8-bit data receiver).

The serial clock is output by the master continuously from the start of an 8-bit data transfer until BUSY is released.

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NEC PD75P402, PD75402A user manual SBI definition, SB0 ACK, SB0 C0 ACK Busy, SB0 D0 ACK Busy