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I/O ports
ST7LITEUS2, ST7LITEUS5
Table 18.
I/O port mode options
(1)
1.
NI stands for not implemented; Off for implemented not activated; On for implemented and activated.
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
Table 19.
I/O port configurations
Hardware configuration
INPUT
(1)
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.
OPE
N
-D
RAI
N
OUT
P
UT
(2
)
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.
PUSH-PULL
O
UTPUT
CONDITION
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
CONDITION
ALTERNATE INPUT
ANALOG INPUT
PAD
R
PU
DATA BUS
DR
DR REGISTER ACCESS
R/W
V
DD
ALTERNATE
ALTERNATE
ENABLE
OUTPUT
REGISTER
PAD
R
PU
DATA BUS
DR
DR REGISTER ACCESS
R/W
V
DD
ALTERNATE
ALTERNATE
ENABLE
OUTPUT
REGISTER
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