CHAPTER 4 PORT FUNCTIONS
(2) Registers
(a) Port 0 register (P0)
The port 0 register (P0) is an 8-bit register that controls pin level read and output level write. This register
can be read/written in 8-bit or 1-bit units.
After Reset: Undefined
R/W
Address: FFFFF400H
P0
0
P06
P05
P04
P03
P02
P01
P00
P0n
0
Control of output data (in output mode) (n = 0 to 6)
Output 0
Output 1
1
Remark In input mode: When read, port 0 (P0) returns the current pin level.
When written to, the data written to P0 is written. This has no
influence on the input pins.
In output mode: When read, port 0 (P0) returns the P0 value. When written to, the
value is written to P0 and the written value is immediately output.
(b) Port 0 mode register (PM0)
This is an 8-bit register that specifies the input mode/output mode.
This register can be read/written in 8-bit or 1-bit units.
After Reset: FFH
R/W
Address: FFFFF420H
PM0
1
PM06
PM05
PM04
PM03
PM02
PM01
PM00
PM0n
Control of I/O mode
0
1
Output mode
Input mode
User’s Manual U15862EJ3V0UD
143
NEC [ NEC ]
