
RL78/G13
CHAPTER 4 PORT FUNCTIONS
R01UH0146EJ0100 Rev.1.00
218
Sep 22, 2011
4.2.9 Port 8
Port 8 is an I/O port with an output latch. Port 8 can be set to the input mode or output mode in 1-bit units using port
mode register 8 (PM8). When the P80 to P87 pins are used as an input port, use of an on-chip pull-up resistor can be
specified in 1-bit units by pull-up resistor option register 8 (PU8).
Input to the P80 and P81 pins can be specified through a normal input buffer or a TTL input buffer in 1-bit units using
port input mode register 8 (PIM8).
Output from the P80 to P82 pin can be specified as N-ch open-drain output (VDD tolerance) in 1-bit units using port
output mode register 8 (POM8).
Reset signal generation sets port 8 to input mode.
Table 4-12. Settings of Registers When Using Port 8
Pin Name
Name
I/O
PM8
×
PIM8
×
POM8
×
Alternate Function Setting
Note 2
Remark
1
0
×
CMOS input
Input
1
×
TTL input
0
×
0
CMOS output
P80
Output
0
×
1
(SCK10/SCL10 output = 1
Note 1
)
N-ch O.D. output
1
0
×
CMOS input
Input
1
×
TTL input
0
×
0
CMOS output
P81
Output
0
×
1
(SDA10 output = 1
Note 1
)
N-ch O.D. output
Input
1
×
0
CMOS output
P82
Output
0
1
(TxD1/SO10 output = 1
Note 1
)
N-ch O.D. output
Input
1
×
P83 to P87
Output
0
×
Notes 1.
To use P80 to P82 as a general-purpose port when PIOR5 = 1, set serial channel enable status register 1
(SE1), serial output register 1 (SO1) and serial output enable register 1 (SOE1) to the default status.
2.
The descriptions in parentheses indicate the case where PIORx = 1.
Remark
×:
don’t care
PM8
×:
Port mode register 8
PIM8
×:
Port input mode register 8
POM8
×:
Port output mode register 8
PIOR
×:
Peripheral I/O redirection register
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