File content as of revision 18:aa8c08f6f474:

#include "mbed.h"
/*
 * HAL_TIM_Encoder_MspInit()
 * Overrides the __weak function stub in stm32f4xx_hal_tim.h
 *
 * Edit the below for your preferred pin wiring & pullup/down
 * I have encoder common at 3V3, using GPIO_PULLDOWN on inputs.
 * Encoder A&B outputs connected directly to GPIOs.
 *
 */

#ifdef TARGET_STM32L0
void HAL_TIM_Encoder_MspInit(TIM_HandleTypeDef *htim)
{
    GPIO_InitTypeDef GPIO_InitStruct;

    if (htim->Instance == TIM2) { //PA0 PA1 = Nucleo A0 A1
        __TIM2_CLK_ENABLE();
        __GPIOA_CLK_ENABLE();
        GPIO_InitStruct.Pin = GPIO_PIN_0 | GPIO_PIN_1;
        GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
        GPIO_InitStruct.Speed = GPIO_SPEED_HIGH;
        GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;
        HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
    }
}
#endif