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(1) Function of P9 pins
Port 9 is a 7-bit I/O port for which I/O settings can be controlled bitwise. I/O settings are controlled via the port 9
mode register (PM9).
During output mode, the values set to each bit are output to the port register (P9).
When using this port in input mode, the pin statuses can be read by reading the P9 register. Also, the P9
register (output latch) values can be read by reading the P9 register while in output mode.
A software pull-up function is not implemented.
When using the P9 for control signals during expansion mode, set the pin functions via the memory expansion
register (MM).
Since BV
is used as the power supply, if BV
DD
occur at ports 0, 1, 3, 7, 8, 10, and 11.
When a reset is input, the settings are initialized to input mode.
(2) Control registers
(a) Port 9 mode register (PM9)
Read and write in 8-bit units and bitwise are enabled.
7FH
After reset:
7
PM9
0
PM9n
0
1
CHAPTER 14
DD
Figure 14-23. Format of Port 9 Mode Register (PM9)
R/W
Address: FFFFF032H
6
5
PM96
PM95
Output mode
Input mode
PORT FUNCTION
and V
have different voltage values, different I/O levels will
DD
4
3
PM94
PM93
Control of I/O Mode
2
1
PM92
PM91
PM90
0
347
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