STM32 HAL one of four PWM pins stays high

Question

I want to use pins A15, B3, B4 and B5 for PWM using Timer2 and Timer3 on STM32F103C8T6. Using code based on one generated by CubeMX i've got pins A15, B3, B4 working properly, but B5 is constantly stuck on high. I tested using normal GPIO, and all four pins can change their states (so it's not issue outside microcontroller)

int main(void)
{
    HAL_Init();
    SystemClock_Config();

    MX_GPIO_Init();
    MX_DMA_Init();
    MX_USART1_UART_Init();
    MX_I2C1_Init();
    MX_ADC1_Init();
    MX_TIM2_Init();
    MX_TIM3_Init();
    MX_TIM4_Init();

    HAL_ADC_Start(&hadc1);
    HAL_ADCEx_Calibration_Start(&hadc1);
    HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_1); //A15
    HAL_TIM_PWM_Start(&htim2, TIM_CHANNEL_2); //B3
    HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_1); //B4
    HAL_TIM_PWM_Start(&htim3, TIM_CHANNEL_2); //B5

    while (1)
    {
        TIM2->CCR1 = 50;
        TIM2->CCR2 = 50;
        TIM3->CCR1 = 50;
        TIM3->CCR2 = 50;
    }   
}

void SystemClock_Config(void)
{

    RCC_OscInitTypeDef RCC_OscInitStruct;
    RCC_ClkInitTypeDef RCC_ClkInitStruct;
    RCC_PeriphCLKInitTypeDef PeriphClkInit;

    /**Initializes the CPU, AHB and APB busses clocks
     */
    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
    RCC_OscInitStruct.HSEState = RCC_HSE_ON;
    RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
    RCC_OscInitStruct.HSIState = RCC_HSI_ON;
    RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
    RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
    RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    /**Initializes the CPU, AHB and APB busses clocks
     */
    RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
            |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
    RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
    RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
    RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
    RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

    if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC;
    PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV6;
    if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    /**Configure the Systick interrupt time
     */
    HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

    /**Configure the Systick
     */
    HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

    /* SysTick_IRQn interrupt configuration */
    HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}

static void MX_TIM2_Init(void)
{

    TIM_ClockConfigTypeDef sClockSourceConfig;
    TIM_MasterConfigTypeDef sMasterConfig;
    TIM_OC_InitTypeDef sConfigOC;

    htim2.Instance = TIM2;
    htim2.Init.Prescaler = 719;
    htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim2.Init.Period = 99;
    htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
    if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
    if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    if (HAL_TIM_PWM_Init(&htim2) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
    sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
    if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = 0;
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    HAL_TIM_MspPostInit(&htim2);

}

/* TIM3 init function */
static void MX_TIM3_Init(void)
{

    TIM_ClockConfigTypeDef sClockSourceConfig;
    TIM_MasterConfigTypeDef sMasterConfig;
    TIM_OC_InitTypeDef sConfigOC;

    htim3.Instance = TIM3;
    htim3.Init.Prescaler = 719;
    htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim3.Init.Period = 99;
    htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim3.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
    if (HAL_TIM_Base_Init(&htim3) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
    if (HAL_TIM_ConfigClockSource(&htim3, &sClockSourceConfig) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    if (HAL_TIM_PWM_Init(&htim3) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
    sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
    if (HAL_TIMEx_MasterConfigSynchronization(&htim3, &sMasterConfig) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    sConfigOC.OCMode = TIM_OCMODE_PWM1;
    sConfigOC.Pulse = 0;
    sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
    sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
    if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    if (HAL_TIM_PWM_ConfigChannel(&htim3, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
    {
        _Error_Handler(__FILE__, __LINE__);
    }

    HAL_TIM_MspPostInit(&htim3);

}

Answer 1

The problem lies in your pin configuration. According to the stm32f103c8t6 datasheet page 28-33, PB5 by default configured as I2C1_SMBAl. PA6 -> TIM3 CH1, PA7 -> TIM3 CH2, PA0 -> TIM2 CH1, PA1 -> TIM2 CH2 are the default pin configurations.

To remap the functions as you want, you have to change AFIO_MARP register. Quoting from STM32F103x family datasheet

To optimize the number of peripherals available for the 64-pin or the 100-pin or the 144-pin package, it is possible to remap some alternate functions to some other pins. This is achieved by software, by programming the AF remap and debug I/O configuration register (AFIO_MAPR). In this case, the alternate functions are no longer mapped to their original assignations.