Electronics America 8-Bit Single-Chip Microcontrollers User's Manual

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CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (

PD78054 Subseries)

(4) 2-wire serial I/O mode (MSB-first)

This mode is used for 8-bit data transfer using two lines of serial clock (SCK0) and serial data bus (SB0 or

SB1).

This mode enables to cope with any one of the possible data transfer formats by controlling the SCK0 level

and the SB0 or SB1 output level. Thus, the handshake line previously necessary for connection of two or

more devices can be used as input/output ports.

Figure 16-1. Serial Bus Interface (SBI) System Configuration Example

Master CPU

SCK0

SB0

SCK0

SB0

Slave CPU1

SCK0

SB0

Slave CPU2

SCK0

SB0

Slave CPUn