UPD784907 Datasheet, PDF (46/98 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784907, 784908
(2) 3-wire serial I/O mode
In this mode, the master device makes the serial clock active to start transmission, then transfers 1-byte data
in synchronization with this clock.
This mode is designed for communication with a device incorporating a conventional synchronous serial interface.
Basically, three lines are used for communication: the serial clock line (SCK) and the two serial data lines (SI
and SO). In general, a handshake line is required to check the state of communication.
Figure 8-12. Block Diagram of 3-Wire Serial I/O Mode
Internal bus
SI1, SI2
Direction control
circuit
SIO1, SIO2
Shift register
Output latch
SO1, SO2
SCK1, SCK2
Serial clock counter
Serial clock
control circuit
Interrupt
generator
INTCSI1,
INTCSI2
1/m
1/2ⁿ⁺¹
fXX
Remark
fXX: Oscillating frequency or external clock input frequency
n = 0 to 11
m = 1, 16 to 30
46
Data Sheet U11680EJ2V0DS00