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CHAPTER 14 SERIAL INTERFACE (SIO3)
Preliminary User’s Manual U16035EJ1V0UM
(2) Serial operation mode register 31 (CSIM31)
This register is used to enable or disable SIO31’s serial clock, operation modes, and specific operations.
CSIM31 is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets CSIM31 to 00H.
Caution
In 3-wire serial I/O mode, set the port mode register (PMXX) as follows. Set the output latch of the port
set to output mode (PMXX = 0) to 0.
<When SIO31 is used>
During serial clock output
PM36 = 0: Sets P36 (SCK31) to output mode
(master transmission or master reception)
P36 = 0: Sets output latch of P36 to 0
During serial clock input
PM36 = 1: Sets P36 (SCK31) to input mode
(slave transmission or slave reception)
Transmit/receive mode
PM35 = 0: Sets P35 (SO31) to output mode
P35 = 0: Sets output latch of P35 to 0
Receive mode
PM34 = 1: Sets P34 (SI31) to input mode