STM32W108C8

General-purpose input/outputs
STM32W108C8
8 General-purpose input/outputs
The STM32W108C8 has 24 multi-purpose GPIO pins that may be individually configured
as:
● General purpose output
● General purpose open-drain output
● Alternate output controlled by a peripheral device
● Alternate open-drain output controlled by a peripheral device
● Analog
● General purpose input
● General purpose input with pull-up or pull-down resistor
The basic structure of a single GPIO is illustrated in Figure 7.
Figure 7.
GPIO block diagram
GPIO_PxCFGH/L
GPIO_PxSET
VDD_PADS
GPIO_PxCLR
GPIO_PxOUT
Output control
(push pull ,
open drain , or
disabled )
P-MOS
N-MOS
VDD_PADS
VDD_PADS
Protection
diode
Alternate output
Alternate input
GND
PIN
GPIO_PxIN
Schmitt trigger
GND
Analog
functions
Protection
diode
GND
Wake detection
GPIO_PxWAKE
A Schmitt trigger converts the GPIO pin voltage to a digital input value. The digital input
signal is then always routed to the GPIO_PxIN register; to the alternate inputs of associated
peripheral devices; to wake detection logic if wake detection is enabled; and, for certain
pins, to interrupt generation logic. Configuring a pin in analog mode disconnects the digital
input from the pin and applies a high logic level to the input of the Schmitt trigger.
Only one device at a time can control a GPIO output. The output is controlled in normal
output mode by the GPIO_PxOUT register and in alternate output mode by a peripheral
device. When in input mode or analog mode, digital output is disabled.
55/215 Doc ID 018587 Rev 2