UG-498
ADuCM320 Hardware Reference Manual
Rev. C | Page 92 of 196
I/O Pull-Up Enable (GPxPUL)
In input mode, GPxPUL enables/disables internal pull-ups/pull-downs. All Port 0 to Port 3 pins have internal pull-ups, and the Port 4 and
Port 5 pins have pull-downs. The pull-ups/pull-downs are implemented as MOS devices, with typical performance shown in Figure 17
and Figure 18.
If a pin is configured as an output, the internal pull-up/pull-down is disabled even in open-drain mode.
10
20
30
40
50
R
OUT
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
VOLTAGE AT PIN (V)
0
20
40
60
80
I
PULL-UP
1117
6-
116
XL
C
3
XL
C
–
6
Figure 17. Typical P0 to P3 Pull-Up Characteristics
10
20
30
40
50
R
OUT
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
VOLTAGE AT PIN (V)
–80
–60
–40
–20
0
I
PULL-DOWN
11
176
-1
17
XL
C
3
XL
C
–
6
Figure 18. Typical P4 to P5 Pull-Down Characteristics