STM32F4發現和CAN編程

Question

我想開始學習編程，我試圖讓這個代碼工作：https://github.com/espruino/Espruino/blob/master/targetlibs/stm32f4/lib/stm32f4xx_can.c 我正在使用Atollic TruStudio Lite。

我用Discovery做了基本的LED閃爍代碼，但除此之外。我不知道如何做到這一點。

我不明白我該如何通過STM32來模擬CAN消息（和其他東西）。

我是一個初學者，所以請不要撕裂我的喉嚨。

感謝

Answer 1

這裏的一個例子可以迴環你可以試試。這是一個CAN環回測試。您可以從STM網站下載stm32f4示例。這是一個STM32439評估板，但它應該可以用於發現。 （兩者都是STM32F4芯片）。

#define USE_CAN1 
/* Uncomment the line below if you will use the CAN 2 peripheral */ 
/* #define USE_CAN2 */ 

#ifdef USE_CAN1 
    #define CANx    CAN1 
    #define CAN_CLK   RCC_APB1Periph_CAN1  

#else /* USE_CAN2 */ 
    #define CANx    CAN2 
    #define CAN_CLK   (RCC_APB1Periph_CAN1 | RCC_APB1Periph_CAN2) 
#endif /* USE_CAN1 */ 

typedef enum {FAILED = 0, PASSED = !FAILED} TestStatus; 

__IO uint32_t ret = 0; /* for return of the interrupt handling */ 
volatile TestStatus TestRx; 

TestStatus CAN_Polling(void); 

int main(void) { 
    /*!< At this stage the microcontroller clock setting is already configured, 
     this is done through SystemInit() function which is called from startup 
     files (startup_stm32f40_41xxx.s/startup_stm32f427_437xx.s/startup_stm32f429_439xx.s) 
     before to branch to application main. 
     To reconfigure the default setting of SystemInit() function, refer to 
     system_stm32f4xx.c file 
    */ 

    /* CANx Periph clock enable */ 
    RCC_APB1PeriphClockCmd(CAN_CLK, ENABLE); 

    /* Initialize LEDs mounted on EVAL board */ 
    STM_EVAL_LEDInit(LED1); 
    STM_EVAL_LEDInit(LED2); 

    /* CAN transmit at 125Kb/s and receive by polling in loopback mode */ 
    TestRx = CAN_Polling(); 

    if (TestRx != FAILED) { /* OK */ 
     /* Turn on LED1 */ 
     STM_EVAL_LEDOn(LED1); 
    } else { /* KO */ 
     /* Turn on LED2 */ 
     STM_EVAL_LEDOn(LED2); 
    } 

    /* Infinite loop */ 
    while (1) { } 
} 

/** 
* @brief Configures the CAN, transmit and receive by polling 
* @param None 
* @retval PASSED if the reception is well done, FAILED in other case 
*/ 
TestStatus CAN_Polling(void) { 
    CAN_InitTypeDef  CAN_InitStructure; 
    CAN_FilterInitTypeDef CAN_FilterInitStructure; 
    CanTxMsg TxMessage; 
    CanRxMsg RxMessage; 
    uint32_t uwCounter = 0; 
    uint8_t TransmitMailbox = 0; 

    /* CAN register init */ 
    CAN_DeInit(CANx); 

    /* CAN cell init */ 
    CAN_InitStructure.CAN_TTCM = DISABLE; 
    CAN_InitStructure.CAN_ABOM = DISABLE; 
    CAN_InitStructure.CAN_AWUM = DISABLE; 
    CAN_InitStructure.CAN_NART = DISABLE; 
    CAN_InitStructure.CAN_RFLM = DISABLE; 
    CAN_InitStructure.CAN_TXFP = DISABLE; 
    CAN_InitStructure.CAN_Mode = CAN_Mode_LoopBack; 
    CAN_InitStructure.CAN_SJW = CAN_SJW_1tq; 

    /* CAN Baudrate = 175kbps (CAN clocked at 42 MHz) */ 
    CAN_InitStructure.CAN_BS1 = CAN_BS1_6tq; 
    CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq; 
    CAN_InitStructure.CAN_Prescaler = 16; 
    CAN_Init(CANx, &CAN_InitStructure); 

    /* CAN filter init */ 
#ifdef USE_CAN1 
    CAN_FilterInitStructure.CAN_FilterNumber = 0; 
#else /* USE_CAN2 */ 
    CAN_FilterInitStructure.CAN_FilterNumber = 14; 
#endif /* USE_CAN1 */ 
    CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask; 
    CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_32bit; 
    CAN_FilterInitStructure.CAN_FilterIdHigh = 0x0000; 
    CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000; 
    CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000; 
    CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000; 
    CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0; 

    CAN_FilterInitStructure.CAN_FilterActivation = ENABLE; 
    CAN_FilterInit(&CAN_FilterInitStructure); 

    /* transmit */ 
    TxMessage.StdId = 0x11; 
    TxMessage.RTR = CAN_RTR_DATA; 
    TxMessage.IDE = CAN_ID_STD; 
    TxMessage.DLC = 2; 
    TxMessage.Data[0] = 0xCA; 
    TxMessage.Data[1] = 0xFE; 

    TransmitMailbox = CAN_Transmit(CANx, &TxMessage); 
    uwCounter = 0; 
    while((CAN_TransmitStatus(CANx, TransmitMailbox) != CANTXOK) && (uwCounter != 0xFFFF)) { 
     uwCounter++; 
    } 

    uwCounter = 0; 
    while((CAN_MessagePending(CANx, CAN_FIFO0) < 1) && (uwCounter != 0xFFFF)) { 
     uwCounter++; 
    } 

    /* receive */ 
    RxMessage.StdId = 0x00; 
    RxMessage.IDE = CAN_ID_STD; 
    RxMessage.DLC = 0; 
    RxMessage.Data[0] = 0x00; 
    RxMessage.Data[1] = 0x00; 
    CAN_Receive(CANx, CAN_FIFO0, &RxMessage); 

    if (RxMessage.StdId != 0x11) { 
     return FAILED; 
    } 

    if (RxMessage.IDE != CAN_ID_STD) { 
     return FAILED; 
    } 

    if (RxMessage.DLC != 2) { 
     return FAILED; 
    } 

    if ((RxMessage.Data[0]<<8|RxMessage.Data[1]) != 0xCAFE) { 
     return FAILED; 
    } 

    return PASSED; /* Test Passed */ 
}