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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
(b) To transmit/receive MSB-first data using an external clock (slave operation).
➤
➤
➤
P01/SCK
µ
PD75402A
SI
SO/SB0
SCK
SO
SI
Other Microcomputer
<Sample program>
Main routine
MOV
XA, #80H
MOV
CSIM, XA
; Serial operation stopped, external clock specification
MOV
XA, TDATA
MOV
SIO, XA
; Transfer data setting & start of transfer
EI
IECSI
EI
Interrupt routine
MOV
XA, TDATA
XCH
XA, SIO
; Receive data
÷
send data & start of transfer
MOV
RDATA, XA
; Receive data save
RETI