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CHAPTER 4 PORT FUNCTIONS
User’s Manual U19780EJ2V0UD
115
(2) Port
registers
(Pxx)
These registers write the data that is output from the chip when data is output from a port.
If the data is read in the input mode, the pin level is read. If it is read in the output mode, the output latch value is
read.
These registers can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears these registers to 00H.
Figure 4-26. Format of Port Register (1/2)
(1) 78K0/KB2-A
Symbol
7 6 5 4 3 2 1 0
Address
After
reset
R/W
P1 0 0 0 0
P13
P12
P11
P10
FF01H
00H
(output
latch)
R/W
P2
0
0 P25 P24 P23 P22 P21 P20 FF02H
00H
(output
latch)
R/W
P3 0 0 P35 0 0 P32
P31 0 FF03H
00H
(output
latch)
R/W
P6 0 0 0 0 0 0
P61
P60
FF06H
00H
(output
latch)
R/W
P8 0 0 0 0
P83
P82
P81
P80
FF08H
00H
(output
latch)
R/W
P12 0 0 0 0 0
P122
Note
P121
Note
P120
FF0CH
00H (output latch)
R/W
m = 1 to 3, 6, 8, 12; n = 0 to 5
Pmn
Output data control (in output mode)
Input data read (in input mode)
0
Output 0
Input low level
1
Output 1
Input high level
Note
“0” is always read from the output latch of P121 and P122 if the pin is in the external clock input
mode.