Alternate Function Configuration; Figure 46. Output Configuration; Figure 47. Alternate Function Configuration - ST STM32WL5 Series Reference Manual

General-purpose I/Os (GPIO)
The figure below shows the output configuration of the I/O port bit.
Write
Read/write
10.3.11

Alternate function configuration

When the I/O port is programmed as alternate function, the following occurs:
• The output buffer can be configured in open-drain or push-pull mode.
•
The output buffer is driven by the signals coming from the peripheral (transmitter
enable and data).
•
The Schmitt trigger input is activated.
•
The weak pull-up and pull-down resistors are activated or not depending on the value
in the GPIOx_PUPDR register.
•
The data present on the I/O pin are sampled into the input data register every AHB
clock cycle.
•
A read access to the input data register gets the I/O state.
The figure below shows the alternate function configuration of the I/O port bit.
To on-chip
peripheral
Write
400/1461

Figure 46. Output configuration

Read

Figure 47. Alternate function configuration

Alternate function input
Read
Read/write
From on-chip
Alternate function output
peripheral
on
TTL Schmitt
trigger
Input driver
Output driver
Output
control
on
TTL Schmitt
trigger
Input driver
Output driver
Output
control
RM0453 Rev 1
V
DDIOx
on/off
pull
up
V
DDIOx
on/off
P-MOS
pull
down
V
SS
N-MOS
Push-pull or
V
SS Open-drain
VDDIOx VDDIOx
on/off
Pul l
up
on/off
V DD
Pul l
P-MOS
down
V SS V
N-MOS
push-pull or
V SS
open-drain
RM0453
V
DDIOx
protection
diode
I/O pin
protection
diode
V
SS
MS31478V1
protection
diode
I/O pin
protection
diode
SS
MSv34756V2