NEC PD75402A - Manual (Page 81)

70
CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
5.5 SERIAL INTERFACE
5.5.1 Serial Interface Functions
The
µ
PD75402A incorporates a clocked 8-bit serial interface, with the following three modes available.
(1) Operation-halted mode
This mode is used when no serial transfer is to be performed, and allows power dissipation to be reduced.
(2) 3-wire serial I/O mode
In this mode, 8-bit data transfer is performed using three lines: The serial clock (SCK), serial output (SO), and
serial input (SI).
In the 3-wire serial I/O mode simultaneous transmission and reception is possible, increasing the data transfer
processing speed.
The 3-wire serial I/O mode allows connection to 75X series and 78K series devices and various peripheral I/O
devices.
Serial data transfer is performed MSB-first.