AT32F425
Series Reference Manual
2022.03.30
Page 85
Ver 2.01
6.2.2
GPIO reset status
After power-on or system reset, all pins are configured as floating input mode except SWD-related pins.
SWD pin configuration are as follows:
PA13/SWDIO multiplexed pull-up
PA14/SWCLK multiplexed pull-down
6.2.3
General-purpose input configuration
Mode
IOMC
PUPD
Floating input
00
00
Pull-down input
10
Pull-up input
01
When I/O port is configured as input:
Get I/O states by reading the input data register.
Floating input, pull-up/pull-down input is configurable
Schmitt-trigger input is activated.
Output is disabled.
Note: In floating input mode, it is recommended to set the unused pins as analog input mode in order to
avoid leakage caused by interference from unused pins in a complex environment.
6.2.4
Analog input/output configuration
Mode
IOMC
PUPD
Analog input/output
11
Unused
When I/O port is configured as analog input:
Schmitt-trigger input is disabled.
Digital input/output is disabled.
Without any pull-up/pull-down resistor.
6.2.5
General-purpose output configuration
Mode
IOMC
OM
HDRV
ODRV[1: 0]
PUPD
Push-Pull without
pull-up/pull-down
01
0
000: Output mode, normal sourcing/sinking strength
001: Output mode, large sourcing/sinking strength
010: Output mode, normal sourcing/sinking strength
011: Output mode, normal sourcing/sinking strength
1xx: Output mode, Maximum sourcing/sinking strength
00 or 11
Push-Pull with pull-up
01
0
01
Push-Pull with pull-down 01
0
10
Open-Drain without pull-
up/pull-down
01
1
000: Output mode, normal sourcing/sinking strength
001: Output mode, large sourcing/sinking strength
010: Output mode, normal sourcing/sinking strength
011: Output mode, normal sourcing/sinking strength
1xx: Output mode, Maximum sourcing/sinking strength
00 or 11
Open-Drain with pull-up 01
1
01
Open-Drain with
pull-down
01
1
10
When I/O port is configured as output:
Schmitt-trigger input is enabled
Output through output register
In open-drain mode, forced output 0, and use pull-up resistor to output 1
In push-pull mode, output register is used to output 0/1
GPIO set/clear register is used to set/clear the corresponding GPIO output data registers
Note: If both IOCB and IOSB bits are set in the GPIO set/clear register, the IOSB takes priority.