CHAPTER 2 PIN FUNCTIONS
26 User’s Manual U10676EJ3V0UM
2.2 Description of Pin Functions
2.2.1 P30 to P33 (Port 3) ... I/O pins shared with PTO0 to PTO2
P60 to P63 (Port 6) ... I/O pins shared with AVREF, INT0, PTH00, PTH01
P80 (Port 8) ... I/O pin
These are 4-bit I/O ports with output latches (ports 3 and 6) and a 1-bit I/O port with an output latch (port 8).
Ports 3 and 6 also have the following functions, in addition to the I/O port function.
• Port 3: Timer counter output (PTO0 to PTO2)
• Port 6: Programmable threshold port reference voltage input (AVREF)
Vectored interrupt input (INT0)
Threshold variable voltage input (PTH00, PTH01)
The input or output mode of ports 3 and 6 is selected by port mode register group A (PMGA), and the input
or output mode of port 8 is selected by port mode register group C (PMGC). Ports 3 and 6 can be set to the input
or output mode in 1-bit units.
Ports 3, 6, and 8 can also be connected to an internal pull-up resistor by software. This is done by manipulating
the pull-up resistor specification registers (POGA and POGB). Specify connection of the pull-up resistor to ports
3 and 6 in 4-bit units. Connection of the pull-up resistor to port 8 can be specified in 1-bit units.
I/O for ports 3 and 6 is possible in 4-bit or 1-bit units. Manipulation in 8-bit units is not possible.
Generation of the RESET signal sets the input mode.
2.2.2 P70 to P73 (Port 7) ... input pins shared with KR4 to KR7
Port 7 is a 4-bit input port.
This port also has a key interrupt input (KR4 to KR7) function, in addition the input port function.
Each pin is always set to input irrespective of the operation of alternate function pins. These pins have Schmitt-
triggered input to prevent malfunction due to noise.
Internal pull-up resistors are specifiable by a mask option in 1-bit units.
2.2.3 PTO0 to PTO2 ... output pins shared with port 3
These are the output pins of timer counters 0 to 2, and output square-wave pulses. To output the signal of a timer
counter, clear the output latch of the corresponding pin of port 3 to “0”. Then, set the bit corresponding to port 3 of
port mode register group A (PMGA) to “1” to set the output mode.
The output of the TOUT F/F pin is cleared to “0” by the timer start instruction.
For details, refer to 6.4.2 (3) Timer counter operation (8-bit).