NEC PD75402A User Manual page 102

(7) 3-wire serial I/O mode applications
(a) To transfer data MSB-first (master operation) using a 262 kHz transfer clock (when operating at 4.19 MHz).
<Sample program>
MOV XA, #10000010B
MOV CSIM, XA
MOV XA, TDATA
MOV SIO, XA
Note From the second time onward, the transfer can be started by setting data in SIO (MOV SIO, XA or XCH XA,
SIO).
In this application the PD75402A SI pin can be used as an input port.
CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
; Transfer mode setting
; TDATA is transfer data storage address
; Transfer data setting & start of transfer
PD75402A
SCK
SO/SB0
SCK
SI
91