CHAPTER 4 PORT FUNCTIONS
Preliminary User’s Manual U16898EJ1V0UD
57
Figure 4-12. Format of Port Mode Register
Address: FF22H, After reset: FFH, R/W
Symbol
7 6 5 4 3 2 1 0
PM2
1 1 1 1
PM23
PM22
PM21
PM20
Address: FF23H, After reset: FFH, R/W
Symbol
7 6 5 4 3 2 1 0
PM3
1 1 1 1 1 1
PM31
PM30
Address: FF24H, After reset: FFH, R/W
Symbol
7 6 5 4 3 2 1 0
PM4
1
1
PM45 PM44 PM43 PM42 PM41 PM40
Address: FF2CH, After reset: FFH, R/W
Symbol
7 6 5 4 3 2 1 0
PM12
1 1 1 1
PM123
PM122
PM121
1
PMmn
Selection of I/O mode of Pmn pin (m = 2, 3, 4, or 12; n = 0 to 7)
0
Output mode (output buffer ON)
1
Input mode (output buffer OFF)
(2) Port registers (P2, P3, P4, P12, P13)
These registers are used to write data to be output from the corresponding port pin to an external device
connected to the chip.
When a port register is read, the pin level is read in the input mode, and the value of the output latch of the
port is read in the output mode.
P20 to P23, P30, P31, P34, P40 to P45, P121 to P123, and P130 are set by using a 1-bit or 8-bit memory
manipulation instruction.
Reset input sets these registers to 00H.
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