Table 27. I/O Port Configurations - STMicroelectronics ST72361 Auto Series Manual

I/O ports
Table 27.
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
I/O PORTS
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.
Caution: The alternate function must not be activated as long as the pin is configured as input with
interrupt, in order to avoid generating spurious interrupts.
Analog alternate function
When the pin is used as an ADC input, the I/O must be configured as floating input. The
analog multiplexer (controlled by the ADC registers) switches the analog voltage present on
the selected pin to the common analog rail which is connected to the ADC input.
It is recommended not to change the voltage level or loading on any port pin while
conversion is in progress. Furthermore it is recommended not to have clocking pins located
close to a selected analog pin.
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I/O port configurations
V
DD
R
PU
PAD
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
V
DD
I/O PORTS
R
PU
PAD
NOT IMPLEMENTED IN
TRUE OPEN DRAIN
V
DD
I/O PORTS
R
PU
PAD
Hardware configuration
PULL-UP
CONDITION
INTERRUPT
CONDITION
Doc ID 12468 Rev 3
ST72361xx-Auto
DR REGISTER ACCESS
W
DR
REGISTER
DATA BUS
R
ALTERNATE INPUT
EXTERNAL INTERRUPT
SOURCE (
ei )
x
ANALOG INPUT
DR REGISTER ACCESS
R/W
DR
REGISTER
ALTERNATE ALTERNATE
ENABLE OUTPUT
DR REGISTER ACCESS
DR R/W
REGISTER
ALTERNATE ALTERNATE
ENABLE OUTPUT
DATA BUS
DATA BUS