CHAPTER 4 PORT FUNCTIONS
User’s Manual U15905EJ2V1UD
114
(2) Registers
(a) Port register 4 (P4)
Port register 4 (P4) is an 8-bit register that controls reading the pin level and writing the output level. This
register can be read or written in 8-bit or 1-bit units.
0
Outputs 0.
Outputs 1.
P4n
0
1
Controls output data (in output mode) (n = 0 to 6)
P4
P46
P45
P44
P43
P42
P41
P40
After reset: Undefined
R/W
Address: FFFFF408H
Remarks 1. In input mode:
When port 4 (P4) is read, the pin level at that time is read. When written, the
data written to P4 is written. The input pin is not affected.
In output mode: When port 4 (P4) is read, the value of P4 is read. When a value is written to P4,
it is immediately output.
2. After reset, an undefined value (pin input level) is read from P4 in the input mode. When P4 is
read in the output mode, 00H (value of the output latch) is read.
(b) Port mode register 4 (PM4)
This is an 8-bit register that specifies the input or output mode.
This register can be read or written in 8-bit or 1-bit units.
1
Output mode
Input mode
PM4n
0
1
Controls input/output mode (n = 0 to 6)
PM4
PM46
PM45
PM44
PM43
PM42
PM41
PM40
After reset: FFH
R/W
Address: FFFFF428H