NEC uPD78056Y - Manual (Page 289)

289
CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
µ
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
V
DD