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AT32F421 GPIO user guide
2020.07.30
11
Rev.1.0.0
Table 6. Configure port B alternate function by GPIOB_AFR register
Pin
name
AF0
AF1
AF2
AF3
AF4
AF5
AF6
AF7
PB0
EVENTOUT
TMR3_CH3
TMR1_CH2N
USART2_RX
-
-
I2S1_MCK
-
PB1
TMR14_CH1
TMR3_CH4
TMR1_CH3N
-
-
-
SPI2_SCK/
I2S2_CK
-
PB2
-
-
TMR3_ETR
-
-
-
-
-
PB3
SPI1_SCK/
I2S1_CK
EVENTOUT
-
-
-
-
SPI2_SCK/
I2S2_CK
-
PB4
SPI1_MISO/
I2S1_MCK
TMR3_CH1
EVENTOUT
-
-
TMR17_BKIN
SPI2_MISO/
I2S2_MCK
I2C2_SDA
PB5
SPI1_MOSI/
I2S1_SD
TMR3_CH2
TMR16_BKIN
I2C1_SMBA
-
-
SPI2_MOSI/
I2S2_SD
-
PB6
USART1_TX
I2C1_SCL
TMR16_CH1N
-
-
-
I2S1_MCK
-
PB7
USART1_RX
I2C1_SDA
TMR17_CH1N
-
-
-
-
-
PB8
-
I2C1_SCL
TMR16_CH1
-
-
-
-
-
PB9
IR_OUT
I2C1_SDA
TMR17_CH1
EVENTOUT
-
I2S1_MCK
-
SPI2_NSS/
I2S2_WS
PB10
-
I2C2_SCL
-
-
-
-
-
SPI2_SCK/
I2S2_CK
PB11
EVENTOUT
I2C2_SDA
-
-
-
-
-
-
PB12
SPI2_NSS/
I2S2_WS
EVENTOUT
TMR1_BKIN
-
-
TMR15_BKIN
-
I2C2_SMBA
PB13
SPI2_SCK/
I2S2_CK
-
TMR1_CH1N
-
-
I2C2_SCL
-
-
PB14
SPI2_MISO/
I2S2_MCK
TMR15_CH1
TMR1_CH2N
-
-
I2C2_SDA
-
-
PB15
SPI2_MOSI/
I2S2_SD
TMR15_CH2
TMR1_CH3N
TMR15_CH1N
-
-
-
-
Table 7. Configure port F alternate function by GPIOF_AFR register
Pin name
AF0
AF1
-
-
-
-
-
-
PF0
-
I2C1_SDA
-
-
-
-
-
-
PF1
-
I2C1_SCL
-
-
-
-
-
-
PF6
I2C2_SCL
-
-
-
-
-
-
-
PF7
I2C2_SDA
-
-
-
-
-
-
-
Special I/Os
Debug alternate function pin
They are in AF mode during reset and after reset, instead of being in input floating mode like
other GPIOs