469CHAPTER 20 SERIAL INTERFACE CHANNEL 220.4 Serial Interface Channel 2 OperationSerial interface channel 2 has the following three modes.• Operation stop mode• Asynchronous serial interface (UART) mode• 3-wire serial I/O mode20.4.1 Operation stop modeIn the operation stop mode, serial transfer is not performed, and therefore power consumption can be reduced.In the operation stop mode, the P70/SI2/RxD, P71/SO2/TxD and P72/SCK2/ASCK pins can be used as normalinput/output ports.(1) Register settingOperation stop mode is set using serial operating mode register 2 (CSIM2) and the asynchronous serialinterface mode register (ASIM).(a) Serial operating mode register 2 (CSIM2)CSIM2 is set with a 1-bit or 8-bit memory manipulation instruction.RESET input sets CSIM2 to 00H.CSIM226 5 4 3 2 1 0<7>SymbolCSIM2 CSIE2 0 0 0 0 CSCK 0 FF72H 00H R/WAddress After Reset R/WCSIE201Operation Control in 3-wire Serial I/O ModeOperation stoppedOperation enabledCaution Ensure that bit 0 and bits 3 through 6 are set to 0.
