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Rev. 1.00, 05/04, page 118 of 544
7.8 Port 8
Port 8 is an 8-bit I/O port. Port 8 pins also function as SCI_1 I/O pins, the IIC_1 I/O pins, LPC I/O
pins, and interrupt input pins. The output type of P86 and SCK1 is NMOS push-pull output. The
output type of SCL1 is NMOS open-drain output and direct bus driving is enabled. Port 8 has the
following registers.
• Port 8 data direction register (P8DDR)
• Port 8 data register (P8DR)
7.8.1 Port 8 Data Direction Register (P8DDR)
P8DDR specifies input or output for the pins of port 8 on a bit-by-bit basis.
Bit Bit Name
Initial
Value
R/W Description
7 — 1 — Reserved
The initial value should not be changed.
6 P86DDR 0 W
5 P85DDR 0 W
4 P84DDR 0 W
3 P83DDR 0 W
2 P82DDR 0 W
1 P81DDR 0 W
0 P80DDR 0 W
P8DDR has the same address as PBPIN, and if read,
the port B state will be returned.
The corresponding port 8 pins are output ports when
P8DDR bits are set to 1, and input ports when cleared
to 0.
7.8.2 Port 8 Data Register (P8DR)
P8DR stores output data for the port 8 pins (P86 to P80).
Bit Bit Name
Initial
Value R/W Description
7 — 1 — Reserved
The initial value should not be changed.
6 P86DR 0 R/W
5 P85DR 0 R/W
4 P84DR 0 R/W
3 P83DR 0 R/W
2 P82DR 0 R/W
1 P81DR 0 R/W
0 P80DR 0 R/W
If a port 8 read is performed while P8DDR bits are set
to 1, the P8DR values are read directly, regardless of
the actual pin states. If a port 8 read is performed while
P8DDR bits are cleared to 0, the pin states are read.