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ML66517 Family User’s Manual
Chapter 5
Port Functions
5 – 26
5.11 Port 8 (P8)
Port 8 is a 6-bit I/O port. Each individual bit can be specified as input or output by the port 8 mode register
(P8IO). When output is specified (corresponding bits of P8IO = “1”), the value of the corresponding bits in the
port 8 data register (P8) will be output from their appropriate pins.
In addition to its port function, P8 is assigned secondary functions (such as SIO1 receive data input). If a
secondary function output is to be used, set the corresponding bits of the port 8 mode register (P8IO) and the port
8 secondary function control register (P8SF) to “1”. If a secondary function input is to be used, reset
corresponding bits of the port 8 mode register (P8IO) to “0” to configure the input mode (same input as the
primary function input).
If the port is set as an input (corresponding bits of P8IO = “0”) and the port 8 secondary function control register
(P8SF) is set to “1”, the pin inputs corresponding to those bits will be pulled-up.
If bit 0 of port 8 is set as a secondary function output (P8IO0 = 1, P8SF0 = 1), the output will be fixed at “0”,
regardless of the value of the port 8 data register.
Figure 5-13 shows the configuration of the port 8 data register (P8), port 8 mode register (P8IO) and the port 8
secondary function control register (P8SF).
Figure 5-13
P8, P8IO, P8SF Configuration
7
P8IO7
6
5
4
3
2
1
0
P8IO6
P8IO2
P8IO3
P8IO1
P8IO0
7
P8SF7
6
5
4
3
2
1
0
P8SF6
TXD1
P8SF1
P8SF0
7
P8_7
6
5
4
3
2
1
0
P8_6
P8_3
P8_2
P8_1
P8_0
0
RXC1
P8SF2
TXC1
P8SF3
0
Not pulled-up
P8_0 input
SIO1 receive
data input
Primary function
P8_0 output
1
Pulled-up
0 output*
Not pulled-up
P8_1 input
Primary function
P8_1 output
Pulled-up
Not pulled-up
P8_2 input
SIO1 receive
clock input
Primary function
P8_2 output
Pulled-up
Not pulled-up
P8_3 output
Pulled-up
Not pulled-up
P8_6 input
Primary function
P8_6 output
Pulled-up
PWM2 output
Not pulled-up
P8_7 input
Primary function
P8_7 output
Pulled-up
PWM3 output
0
1
0
1
0
1
0
1
0
1
0 (Input setting)
1 (Output setting)
P8IO
At reset
P8SF
At reset
P8
At reset
Address: 00C8 [H]
R/W access: R/W
Address: 00C0 [H]
R/W access: R/W
Address: 00B8 [H]
R/W access: R/W
P8_3 input
SIO1 transmit
clock input
Primary function
0 output*: “0” is output, regardless of the value of the port data register
“
” indicates a bit that does not exist. If read, the value will be “0”.
PWM3OUT PWM2OUT
Secondary function
SIO1 transmit data output
SIO1 receive clock output
SIO1 transmit clock output