Datasheet

CHAPTER 4 PORT FUNCTIONS
User’s Manual U18172EJ3V0UD
55
Table 4-2. Port Functions ( μ PD78F950x)
Pin Name I/O Function After Reset Alternate-
Function Pin
P20 TOH1
P21 INTP0
P22
−
P23
Note
I/O Port 2.
4-bit I/O port.
Can be set to input or output mode in 1-bit units.
On-chip pull-up resistor can be connected by setting software.
Input
EXCLK
Note
P32 I/O Can be set to input or output mode in 1-
bit units.
Input INTP1
P34
Note
Input
Port 3.
On-chip pull-up
resistor can be
connected by
setting software.
Input only Input
RESET
Note
P40 and P43 I/O Port 4.
2-bit I/O port.
Can be set to input or output mode in 1-bit units.
On-chip pull-up resistor can be connected setting software.
Input
−
Note For the setting method for pin functions, see CHAPTER 15 OPTION BYTE.
Caution The P22 and P23/EXCLK pins are pulled down during reset. The P34/RESET pin is pulled up during
reset by the reset pin function/power-on clear circuit.
Remark P23 can be allocated when the high-speed internal oscillation is selected as the system clock.
4.2 Port Configuration
Ports consist of the following hardware units.
Table 4-3. Configuration of Ports
Item Configuration
Control registers Port mode registers (PM2 to PM4)
Port registers (P2 to P4)
Port mode control register 2 (PMC2) (
μ PD78F920x only)
Pull-up resistor option registers (PU2 to PU4)
Ports Total: 8 (CMOS I/O: 7, CMOS input: 1)
Pull-up resistor Total: 7
<R>
<R>