Datasheet

ST72321Rx ST72321ARx ST72321Jx
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I/O PORTS (Cont’d)
Figure 30. I/O Port General Block Diagram
Table 10. I/O Port Mode Options
Legend: NI - not implemented
Off - implemented not activated
On - implemented and activated
Note: The diode to V
DD
is not implemented in the
true open drain pads. A local protection between
the pad and V
SS
is implemented to protect the de-
vice against positive stress.
Configuration Mode Pull-Up P-Buffer
Diodes
to V
DD
to V
SS
Input
Floating with/without Interrupt Off
Off
On
On
Pull-up with/without Interrupt On
Output
Push-pull
Off
On
Open Drain (logic level) Off
True Open Drain NI NI NI (see note)
DR
DDR
OR
DATA BUS
PAD
V
DD
ALTERNATE
ENABLE
ALTERNATE
OUTPUT
1
0
OR SEL
DDR SEL
DR SEL
PULL-UP
CONDITION
P-BUFFER
(see table below)
N-BUFFER
PULL-UP
(see table below)
1
0
ANALOG
INPUT
If implemented
ALTERNATE
INPUT
V
DD
DIODES
(see table below)
EXTERNAL
SOURCE (ei
x
)
INTERRUPT
CMOS
SCHMITT
TRIGGER
REGISTER
ACCESS