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Port 1 Register (PORT1)
Bit
:
Initial value :
R/W
:
Note: * Determined by state of pins P17 to P10.
PORT1 is an 8-bit read-only register that shows the pin states. It cannot be written to. Writing of
output data for the port 1 pins (P17 to P10) must always be performed on P1DR.
If a port 1 read is performed while P1DDR bits are set to 1, the P1DR values are read. If a port 1
read is performed while P1DDR bits are cleared to 0, the pin states are read.
After a power-on reset and in hardware standby mode, PORT1 contents are determined by the pin
states, as P1DDR and P1DR are initialized. PORT1 retains its prior state by a manual reset or in
software standby mode.
334
7
6
P17
P16
—*
—*
R
R
5
4
P15
P14
—*
—*
R
R
3
2
P13
P12
—*
—*
R
R
1
0
P11
P10
—*
—*
R
R
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