
CHAPTER 2 PIN FUNCTIONS
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2.2.3 TI0, TI1 ... inputs shared with port 1
These are the external pulse event input pins of timers/event counters 0 and 1.
These can be used by selecting external event pulse input to the count pulse (CP) using the timer/event counter
mode register (TM0, TM1).
TI0 and TI1 are Schmitt trigger input pins.
2.2.4 PTO0, PTO1 ... outputs shared with port 2
These are the output pins of timers/event counters 0 and 1, and output square wave pulses. To output the signal
of a timer/event counter, clear the output latch of the corresponding pin of port 2 to “0”. Then, set the bit corresponding
to port 2 of the port mode register to “1” to set the output mode.
The outputs of TOUT F/F are cleared to “0” by the timer start instruction.
For details, refer to
5.5.2(3) Operation in 8-bit timer/event counter mode.
2.2.5 PCL ... output shared with port 2
This is a programmable clock output pin and is used to supply the clock to a peripheral LSI (such as a slave
microcontroller). When the RESET signal is asserted, the contents of the clock output mode register (CLOM) are
cleared to “0”, disabling the output of the clock. In this case, the PCL pin can be used as an ordinary port pin.
For details, refer to
5.2.4 Clock output circuit.
2.2.6 BUZ ... output shared with port 2
This is a frequency output pin and is used to issue a buzzer sound or trim the system clock frequency by outputting
a specified frequency (2, 4, or 32 kHz @4.19 MHz with main system clock, or @32.768 kHz with subsystem clock).
This pin is shared with the P23 pin and is valid only when the bit 7 (WM7) of the watch mode register (WM) is set
to “1”.
When the RESET signal is asserted, WM7 is cleared to 0, so that the BUZ pin is used as an ordinary port pin.
For details, refer to
5.4.2 Watch mode register.
2.2.7 SCK, SO/SB0, and SI/SB1 ... I/Os shared with port 0
These are serial interface I/O pins and operate according to the setting of the serial operation mode register (CSIM).
When the three-wire serial I/O mode is selected, the SCK, SO, and SI pins function as CMOS I/O, CMOS output,
CMOS input, respectively. When the two-wire serial I/O mode is selected, the SCK and SB1(SB0) pins function as
CMOS I/O and N-ch open-drain I/O, respectively.
When the RESET signal is asserted, the serial interface operation is stopped, and these pins served as input port
pins.
All these pins are Schmitt trigger input pins.
For details, refer to
5.6 Serial Interface
.
2.2.8 INT4 ... input shared with port 0
This is an external vector interrupt input pin and becomes active at both the rising and falling edges. The interrupt
request flag is set whenever there is a positive or negative transition of the signal input to this pin.
INT4 is an asynchronous input pin and the interrupt is acknowledged whenever a high- or low-level signal is input
to this pin for a fixed time, regardless of the operating clock of the CPU.
INT4 can also be used to release the STOP and HALT modes. This pin is a Schmitt trigger input pin.