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MSM66573 Family User's Manual
Chapter 5 Port Functions
5.12 Port 8 (P8)
Port 8 is a 7-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 5-15 shows the configuration of the port 8 data register (P8), port 8 mode register
(P8IO) and the port 8 secondary function control register (P8SF).
7
P8IO7
6
5
4
3
2
1
0
P8IO6
P8IO2
P8IO3
P8IO1
P8IO0
7
PWM3OUT
P8SF7
6
5
4
3
2
1
0
PWM2OUT
P8SF6
TXD1
P8SF1
P8SF0
7
P8_7
6
5
4
3
2
1
0
P8_6
P8_3
P8_2
P 8 _1
P8_0
000
0
00
0
00
000
0
RXC1
P8SF2
TXC1
P8SF3
—
P8IO4
PTM4OUT
P8SF4
P8_4
0
Not pulled-up
P8_0 input
SIO1 receive
data input
Primary function
P8_0 output
1
Pulled-up
Secondary function
0 output*
Not pulled-up
P8_1 input
Primary function
P8_1 output
Pulled-up
Secondary function SIO1 transmit data output
Not pulled-up
P8_2 input
SIO1 receive
clock input
Primary function
P8_2 output
Pulled-up
Secondary function SIO1 receive clock output
Not pulled-up
P8_3 output
Pulled-up
Secondary function SIO1 transmit clock output
Not pulled-up
P8_4 output
Pulled-up
Secondary function Timer 4 output
Not pulled-up
P8_6 input
Primary function
P8_6 output
Pulled-up
Secondary function PWM2 output
Not pulled-up
P8_7 input
Primary function
P8_7 output
Pulled-up
Secondary function PWM3 output
0
1
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:
R/W access:
00C8 [H]
R/W
Address:
R/W access:
00C0 [H]
R/W
Address:
R/W access:
00B8 [H]
R/W
P8_3 input
SIO1 transmit
clock input
Primary function
P8_4 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."
Figure 5-15 P8, P8IO, P8SF Configuration