
CHAPTER 4 PORT FUNCTIONS
User’s Manual U15905EJ2V1UD
128
(2) Registers
(a) Port register 9 (P9)
Port register 9 (P9) is a 16-bit register that controls reading a pin level and writing an output level. This
register can be read or written in 16-bit units.
If the higher 8 bits of the P9 register is used as P9H and the lower 8 bits as P9L, however, P9H and P9L
can be manipulated in 8-bit or 1-bit units.
P915
Outputs 0.
Outputs 1.
P9n
0
1
Controls output data (in output mode) (n = 0 to 15)
P9 (P9HNote)
(P9L)
P914
P913
P912
P911
P910
P99
P98
After reset: Undefined
R/W
Address: P9 FFFFF412H,
P9L FFFFF412H, P9H FFFFF413H
P97
P96
P95
P94
P93
P92
P91
P90
8
9
10
11
12
13
14
15
Note
When reading or writing bits 8 to 15 of the P9 register in 8-bit or 1-bit units, specify these bits as bits 0 to
7 of the P9H register.
Remarks 1. In input mode:
When port 9 (P9) is read, the pin level at that time is read. When written, the
data written to P9 is written. The input pin is not affected.
In output mode: When port 9 (P9) is read, the value of P9 is read. When a value is written to P9,
it is immediately output.
2. After reset, an undefined value (pin input level) is read from P9 in the input mode. When P9 is
read in the output mode, 00H (value of the output latch) is read.