Datasheet

ST72334J/N, ST72314J/N, ST72124J
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I/O PORTS (Cont’d)
Table 7. I/O Port Configurations
Notes:
1. When the I/O port is in input configuration and the associated alternate function is enabled as an output,
reading the DR register will read the alternate function output status.
2. When the I/O port is in output configuration and the associated alternate function is enabled as an input,
the alternate function reads the pin status given by the DR register content.
Hardware Configuration
INPUT
1)
OPEN-DRAIN OUTPUT
2)
PUSH-PULL OUTPUT
2)
CONFIGURATION
PAD
V
DD
R
PU
EXTERNAL INTERRUPT
POLARITY
DATA BUS
PULL-UP
INTERRUPT
DR REGISTER ACCESS
W
R
FROM
OTHER
PINS
SOURCE (ei
x
)
SELECTION
DR
REGISTER
CONFIGURATION
ALTERNATE INPUT
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
I/O PORTS
ANALOG INPUT
PAD
R
PU
DATA BUS
DR
DR REGISTER ACCESS
R/W
V
DD
ALTERNATEALTERNATE
ENABLE OUTPUT
REGISTER
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
I/O PORTS
PAD
R
PU
DATA BUS
DR
DR REGISTER ACCESS
R/W
V
DD
ALTERNATEALTERNATE
ENABLE OUTPUT
REGISTER
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
I/O PORTS