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5. I/O Ports
5.3 Port P3 (P33 to P30)
5.3 Port P3 (P33 to P30)
Port P3 is a 4-bit input/output port.
It is also used as a timer/counter input/output, divider output.
When used as a timer/counter output or divider output, respective output latch (P3DR) should be set to "1".
It can be selected whether output circuit of P3 port is C-MOS output or a sink open drain individually, by setting
P3OUTCR. When a corresponding bit of P3OUTCR is "0", the output circuit is selected to a sink open drain and
when a corresponding bit of P3OUTCR is "1", the output circuit is selected to a C-MOS output. When used as an
input port or timer/counter input, respective output control (P3OUTCR) should be set to "0" after P3DR is set to "1".
During reset, the P3DR is initialized to "1", and the P3OUTCR is initialized to "0".
P3 port output latch (P3DR) and P3 port terminal input (P3PRD) are located on their respective address.
When read the output latch data, the P3DR should be read and when read the terminal input data, the P3PRD reg-
ister should be read. If a read instruction is executed for port P3, read data of bits 7 to 4 are unstable.
Port P3 control register
P3DR
(0003H)
R/W
P3OUTCR
(0004H)
P3OUTCR
P3PRD
(000AH)
Read only
STOP
OUTEN
P3OUTCRi
P3OUTCRi input
ata input (P3PR )
ata input (P3 R)
ata output (P3 R)
Control output
Control input
7
6
5
4
7
6
5
4
Port P3 output circuit control
(set for each bit individually)
7
6
5
4
Q
Q
Figure 5-4 Port P3
3
2
1
P33
P32
P31
PWM6
PWM4
PWM3
PDO6
PDO4
PDO3
TC3
PPG6
PPG4
TC6
TC4
3
2
1
0: Sink open-drain output
1: C-MOS ouput
3
2
1
P33
P32
P31
Page 54
TMP86PM29BUG
P3i
to
Note: i = 3
0
0
P30
DVO
(Initial value: **** 1111)
0
(Initial value: **** 0000)
0
P30
R/W
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