
CHAPTER 4 PORT FUNCTIONS
User’s Manual U15905EJ2V1UD
109
(e) Port function register 3 (PF3)
This 8-bit register specifies normal output or N-ch open-drain output.
It can be read or written in 8-bit or 1-bit units.
0
Normal output
N-ch open-drain output
PF3n
0
1
Controls normal output or N-ch open-drain output (n = 1, 2)
PF3
0
PF32
PF31
0
After reset: 00H
R/W
Address: FFFFFC66H
Cautions 1. The N-ch open-drain output voltage is the normal voltage, not the medium voltage.
2. PF3n = 1 is enabled only in the following cases. Otherwise, the setting is prohibited.
n = 1: SO1
n = 2: SCK1
(f) Pull-up resistor option register 3 (PU3)
This is an 8-bit register that specifies connection of an internal pull-up resistor.
This register can be read or written in 8-bit or 1-bit units.
0
Not connected.
Connected.
PU3n
0
1
Controls connection of internal pull-up resistor (n = 0 to 2)
PU3
0
PU32
PU31
PU30
After reset: 00H
R/W
Address: FFFFFC46H