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MSM66573 Family User's Manual
Chapter 5 Port Functions
5.13 Port 9 (P9)
Port 9 is a 5-bit I/O port. Each individual bit can be specified as input or output by the port
9 mode register (P9IO). When output is specified (corresponding bits of P9IO = "1"), the
value of the corresponding bits in the port 9 data register (P9) will be output from their
appropriate pins.
In addition to its port function, P9 is assigned secondary functions (such as external
interrupt input). If a secondary function output is to be used, set the corresponding bits of
the port 9 mode register (P9IO) and the port 9 secondary function control register (P9SF)
to "1". If a secondary function input is to be used, reset corresponding bits of the port 9 mode
register (P9IO) 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 P9IO = "0") and the port 9 secondary
function control register (P9SF) is set to "1", the pin inputs corresponding to those bits will
be pulled-up.
If bits 0 to 3 of port 9 are set as secondary function outputs (P9IOn = 1, P9SFn = 1), the
output will be fixed at "0", regardless of the value of the port 9 data register.
Figure 5-16 shows the configuration of the port 9 data register (P9), port 9 mode register
(P9IO) and the port 9 secondary function control register (P9SF).
7
6
5
4
3
2
1
0
P9IO3
P9IO2
P9IO1
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
P9_7
P9_3
P 9 _2
P9_1
000
0
00
0
00
000
0
HLDACK
P9SF7
P9SF3
—
——
P9SF2
P9SF1
P9IO7
P9IO0
P9_0
P9SF0
0
Not pulled-up
P9_0 input
External interrupt
4 input
Primary function
P9_0 output
1
Pulled-up
Secondary function
0 output*
Not pulled-up
P9_1 input
External interrupt
5 input
Primary function
P9_1 output
Pulled-up
Secondary function
0 output*
Not pulled-up
Primary function
P9_2 output
Pulled-up
Secondary function
0 output*
Not pulled-up
P9_3 output
Pulled-up
Secondary function
0 output*
Not pulled-up
P9_7 output
Pulled-up
Secondary function HLDACK output
0
1
0
1
0
1
0
1
0 (Input setting)
1 (Output setting)
P9IO
At reset
P9SF
At reset
P9
At reset
Address:
R/W access:
00C9 [H]
R/W
P9_7 input
Primary function
Address:
R/W access:
00C1 [H]
R/W
Address:
R/W access:
00B9 [H]
R/W
P9_3 input
Primary function
P9_2 input
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 5-16 P9, P9IO, P9SF Configuration