uPD789074 Subseries 8-Bit Single-Chip Microcontrollers UD - Home

CHAPTER 2 PIN FUNCTIONS(2) Non-port pinsPin Name I/O Function After Reset Alternate FunctionINTP0INTP1INTP2InputExternal interrupt input for which the valid edge (rising edge,falling edge, or both rising and falling edges) can be specifiedInputP24P25P26/CPT90SCK20 I/O Serial interface (SIO10) serial clock input Input P20/ASCK20SI20 Input Serial interface (SIO20) serial data input Input P22/RxD20SO20 Output Serial interface (SIO20) serial data output Input P21/TxD20SS20 Input Serial interface chip select input Input P23ASCK20 Input Serial clock input for asynchronous serial interface Input P20/SCK20RxD20 Input Serial data input for asynchronous serial interface Input P22/SI20TxD20 Output Serial data output for asynchronous serial interface Input P21/SO20TO90 Output 16-bit timer (TM90) output Input P30BZO90 Output Buzzer output Input P31CPT90 Input Capture edge input Input P26/INTP2TO80 Output 8-bit timer (TM80) output Input P27/TI80TI80 Input External count clock input to 8-bit timer (TM80) Input P27/TO80X1 Input Connecting crystal resonator for system clock oscillation− −X2−−−RESET Input System reset input Input −VDD − Positive supply voltage − −VSS − Ground potential − −IC − Internally connected. Connect directly to VSS. − −VPP − This pin is used to set the flash memory programming modeand applies a high voltage when a program is written orverified.−−User’s Manual U14801EJ3V1UD 31