AN3422 datasheet(44/52 Pages) STMICROELECTRONICS

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Firmware migration using the library

AN3422

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Doc ID 018976 Rev 2

5.4

GPIO

This section explains how to update the configuration of the various GPIO modes when

porting the application code from STM32F1 series to STM32L1 series.

5.4.1

Output mode

The example below shows how to configure an I/O in output mode (for example to drive a

led) in STM32F1 series:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_xxMHz; /* 2, 10 or 50 MHz */

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_Init(GPIOy, &GPIO_InitStructure);

In L1 series you have to update this code as follows:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; /* Push-pull or open drain */

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; /* None, Pull-up or pull-down */

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_xxMHz; /* 400 KHz, 2, 10 or 40MHz */

GPIO_Init(GPIOy, &GPIO_InitStructure);

5.4.2

Input mode

The example below shows how to configure an I/O in input mode (for example to be used as

an EXTI line) in STM32F1 series:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOy, &GPIO_InitStructure);

In L1 series you have to update this code as follows:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; /* None, Pull-up or pull-down */

GPIO_Init(GPIOy, &GPIO_InitStructure);

5.4.3

Analog mode

The example below shows how to configure an I/O in analog mode (for example an ADC or

DAC channel) in STM32F1 series:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;

GPIO_Init(GPIOy, &GPIO_InitStructure);

In L1 series you have to update this code as follows:

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_x ;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;

GPIO_Init(GPIOy, &GPIO_InitStructure);

AN3422 Datasheet(PDF) 44 Page - STMicroelectronics

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