Register To Control Serial Interface Sio3 - NEC mPD780344 Series User Manual

8-bit single-chip microcontrollers

Table of Contents

14.3 Register to Control Serial Interface SIO3

The serial interface SIO3 is controlled by serial operation mode register 3 (CSIM3).

(1) Serial operation mode register 3 (CSIM3)

This register is used to enable or disable SIO3's serial clock, operation modes, and specific operations.

CSIM3 is set by a 1-bit or 8-bit memory manipulation instruction.

RESET input sets the value of this register to 00H.

Caution In 3-wire serial I/O mode, set the port mode register (PMXX) as follows. Set the output latch

of a port set to output mode (PMXX = 0) to 0.

During serial clock output

(master transmission or master reception)

During serial clock input

(slave transmission or slave reception)

Transmit/receive mode

Receive mode

CHAPTER 14 SERIAL INTERFACE SIO3

PM22 = 0; Sets P22 (SCK3) to output mode

P22 = 0; Sets output latch of P22 to 0

PM22 = 1; Sets P22 (SCK3) to input mode

PM21 = 0; Sets P21 (SO3) to output mode

P21 = 0; Sets output latch of P21 to 0

PM20 = 1; Sets P20 (SI3) to input mode

User's Manual U15798EJ2V0UD