UPD784218 Datasheet, PDF (41/92 Pages) NEC – 16-/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784218, 784218Y
(2) 3-wire serial I/O mode
In this mode, the master device starts transfer by making the serial clock active and transfers 1-byte data
in synchronization with this clock.
This mode is used to communicate with a device having the conventional clocked serial interface. Basically,
communication is established by using three lines: serial clocks (SCK1 and SCK2), serial data inputs (SI1
and SI2), and serial data outputs (SO1 and SO2). To connect two or more devices, a handshake line is
necessary.
Figure 8-11. Block Diagram When in 3-Wire Serial I/O Mode
Internal bus
SI1, SI2
SO1, SO2
SCK1, SCK2
8
Serial I/O shift register
1, 2 (SIO1, SIO2)
Serial clock
counter
Serial clock
controller
Interrupt
generator
Selector
INTCSI1,
INTCSI2
TO2
fXX/8
fXX/16
Data Sheet U12304EJ2V0DS00
41