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Found a bug in STM32F103RB CAN init for D14,D15

Topic last updated 14 Dec 2016, by Bill Bellis. 0 replies
Bill Bellis
14 Dec 2016

Hi ST Team I found a bug in the init of the STM32F103RB. When trying to use D14,D15 (alternate function 2 for CAN) the IO is set up incorrectly. The issue is shown below. With my posted corrections it is now working correctly. Is it possible to get this fix into the next mbed release?

In PeripheralPins.c the following lines of code incorrectly assign the SPI alternate function instead of the CAN alternate function. I was able to get D15,D14 working once I change the "1" to "10" and then added a case statement for initialization 10 inside of

Original code:

const PinMap PinMap_CAN_RD[] = {
    {PA_11, CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 0)},
    {PB_8 , CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 1)},
    {NC,    NC,    0}
};

const PinMap PinMap_CAN_TD[] = {
    {PA_12,  CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 0)},
    {PB_9 ,  CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 1)},
    {NC,    NC,    0}

Corrected code

const PinMap PinMap_CAN_RD[] = {
    {PA_11, CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 0)},
    {PB_8 , CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 10)},  //SET ALTERNATE2 CAN FUNCTION type 10
    {NC,    NC,    0}
};

const PinMap PinMap_CAN_TD[] = {
    {PA_12,  CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 0)},
    {PB_9 ,  CAN_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_NOPULL, 10)},
    {NC,    NC,    0}
};

In addition I made changes to pinmap.c to accommodate a 10th case within the following function:

/**
 * Configure pin (input, output, alternate function or analog) + output speed + AF
 */
void pin_function(PinName pin, int data)
{
    MBED_ASSERT(pin != (PinName)NC);
    // Get the pin informations
    uint32_t mode  = STM_PIN_MODE(data);
    uint32_t pupd  = STM_PIN_PUPD(data);
    uint32_t afnum = STM_PIN_AFNUM(data);

    uint32_t port_index = STM_PORT(pin);
    uint32_t pin_index  = STM_PIN(pin);

    // Enable GPIO clock
    uint32_t gpio_add = Set_GPIO_Clock(port_index);
    GPIO_TypeDef *gpio = (GPIO_TypeDef *)gpio_add;

    // Enable AFIO clock
    __HAL_RCC_AFIO_CLK_ENABLE();

    // Configure Alternate Function
    // Warning: Must be done before the GPIO is initialized
    if (afnum > 0) {
        switch (afnum) {
            case 1: // Remap SPI1
                __HAL_AFIO_REMAP_SPI1_ENABLE();
                break;
            case 2: // Remap I2C1
                __HAL_AFIO_REMAP_I2C1_ENABLE();
                break;
            case 3: // Remap USART1
                __HAL_AFIO_REMAP_USART1_ENABLE();
                break;
            case 4: // Remap USART2
                __HAL_AFIO_REMAP_USART2_ENABLE();
                break;
            case 5: // Partial Remap USART3
                __HAL_AFIO_REMAP_USART3_PARTIAL();
                break;
            case 6: // Partial Remap TIM1
                __HAL_AFIO_REMAP_TIM1_PARTIAL();
                break;
            case 7: // Partial Remap TIM3
                __HAL_AFIO_REMAP_TIM3_PARTIAL();
                break;
            case 8: // Full Remap TIM2
                __HAL_AFIO_REMAP_TIM2_ENABLE();
                break;
            case 9: // Full Remap TIM3
                __HAL_AFIO_REMAP_TIM3_ENABLE();
                break;
            case 10://Remap CAN1 on to PB_8 PB_9
                __HAL_AFIO_REMAP_CAN1_2();
                break;
            default:
                break;
        }
    }

    // Configure GPIO
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.Pin   = (uint32_t)(1 << pin_index);
    GPIO_InitStructure.Mode  = gpio_mode[mode];
    GPIO_InitStructure.Pull  = pupd;
    GPIO_InitStructure.Speed = GPIO_SPEED_HIGH;
    HAL_GPIO_Init(gpio, &GPIO_InitStructure);

    // Disconnect JTAG-DP + SW-DP signals.
    // Warning: Need to reconnect under reset
    if ((pin == PA_13) || (pin == PA_14)) {
        __HAL_AFIO_REMAP_SWJ_DISABLE(); // JTAG-DP Disabled and SW-DP Disabled
    }
    if ((pin == PA_15) || (pin == PB_3) || (pin == PB_4)) {
        __HAL_AFIO_REMAP_SWJ_NOJTAG(); // JTAG-DP Disabled and SW-DP enabled
    }
}

Thank you Bill