Gpio Functional Description; Gpio Abbreviations - ST STM32 Application Note

GPIO functional description

4 GPIO functional description
STM32 GPIO can be used in a variety of configurations. Each GPIO pin can be individually
configured by software in any of the following modes:
•
Input floating
•
Input pull-up
•
Input-pull-down
•
Analog
•
Output open-drain with pull-up or pull-down capability
•
Output push-pull with pull-up or pull-down capability
•
Alternate function push-pull with pull-up or pull-down capability
•
Alternate function open-drain with pull-up or pull-down capability
4.1

GPIO abbreviations

Several GPIO structures are available across the range of STM32 devices. Each structure
is associated with a list of options.
Table 1 summarizes the GPIO definitions and abbreviations applicable to STM32 products
Name
Pin Type
I/O structure
Alternate functions Functions selected through GPIOx_AFR registers
Pin functions
Additional functions Functions directly selected and enabled through peripheral registers
1. FT and TT I/Os have options depending on the device. The user must refer to the datasheet for their definitions.
As an example, the following description refers to a GPIO in a STM32 datasheet:
PB1 I/O FT means:
–
–
Before starting a board design, it is important to refer to the datasheet of the STM32 product
or to the STM32CubeMX tool to check for GPIO availability in coherence with the target
application.
Refer to the section about software development tools at www.st.com/stm32.
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Table 1. List of GPIO structures
Abbreviation
S
I
I/O
(1)
FT
(1)
TT
TC
B
RST
pin PB1 I/O: port B bit 1 input / output
FT: five-volt tolerant
Supply pin
Input only pin
Input / output pin
Five-volt tolerant I/O pin
Three-volt tolerant I/O pin
Three-volt capable I/O pin (Standard 3.3 V I/O)
Dedicated boot pin
Bidirectional reset pin with embedded weak pull-up resistor
AN4899 Rev 3
Definition
AN4899