stm32mp15x 之 M4 使用 canfd

序

在使用 stm32mp15x 系列时，M4 有不少的坑，这里简单聊聊使用 canfd 时遇到的一些问题。

配置

这里使用 PLL4R 为 100M，用于 CANFD 的时钟

canfd 速率配置成 1M ，5M，其中数据传输速率为 5M。

接收采用 RxFifo0，发送采用 FIFO 模式，发送和接收数据长度都配置成 64字节，tx、rx 深度都配置成 15。

配置 FDCAN2 中断 0 就可以。

配置生成如下：

void MX_FDCAN2_Init(void)
{hfdcan2.Instance = FDCAN2;hfdcan2.Init.FrameFormat = FDCAN_FRAME_FD_BRS;hfdcan2.Init.Mode = FDCAN_MODE_NORMAL;hfdcan2.Init.AutoRetransmission = ENABLE;hfdcan2.Init.TransmitPause = DISABLE;hfdcan2.Init.ProtocolException = DISABLE;hfdcan2.Init.NominalPrescaler = 2;hfdcan2.Init.NominalSyncJumpWidth = 16;hfdcan2.Init.NominalTimeSeg1 = 33;hfdcan2.Init.NominalTimeSeg2 = 16;hfdcan2.Init.DataPrescaler = 1;hfdcan2.Init.DataSyncJumpWidth = 4;hfdcan2.Init.DataTimeSeg1 = 15;hfdcan2.Init.DataTimeSeg2 = 4;hfdcan2.Init.MessageRAMOffset = 0;hfdcan2.Init.StdFiltersNbr = 1;hfdcan2.Init.ExtFiltersNbr = 0;hfdcan2.Init.RxFifo0ElmtsNbr = 15;hfdcan2.Init.RxFifo0ElmtSize = FDCAN_DATA_BYTES_64;hfdcan2.Init.RxFifo1ElmtsNbr = 0;hfdcan2.Init.RxFifo1ElmtSize = FDCAN_DATA_BYTES_8;hfdcan2.Init.RxBuffersNbr = 0;hfdcan2.Init.RxBufferSize = FDCAN_DATA_BYTES_8;hfdcan2.Init.TxEventsNbr = 0;hfdcan2.Init.TxBuffersNbr = 0;hfdcan2.Init.TxFifoQueueElmtsNbr = 15;hfdcan2.Init.TxFifoQueueMode = FDCAN_TX_FIFO_OPERATION;hfdcan2.Init.TxElmtSize = FDCAN_DATA_BYTES_64;if (HAL_FDCAN_Init(&hfdcan2) != HAL_OK){Error_Handler();}}void HAL_FDCAN_MspInit(FDCAN_HandleTypeDef* fdcanHandle)
{GPIO_InitTypeDef GPIO_InitStruct = {0};RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};if(fdcanHandle->Instance==FDCAN2){/* USER CODE BEGIN FDCAN2_MspInit 0 *//* USER CODE END FDCAN2_MspInit 0 */if(IS_ENGINEERING_BOOT_MODE()){/** Initializes the peripherals clock*/PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_FDCAN;PeriphClkInit.FdcanClockSelection = RCC_FDCANCLKSOURCE_PLL4_R;if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK){Error_Handler();}}/* FDCAN2 clock enable */__HAL_RCC_FDCAN_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();/**FDCAN2 GPIO ConfigurationPB12     ------> FDCAN2_RXPB13     ------> FDCAN2_TX*/GPIO_InitStruct.Pin = GPIO_PIN_12;GPIO_InitStruct.Mode = GPIO_MODE_AF;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Alternate = GPIO_AF9_FDCAN2;HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);GPIO_InitStruct.Pin = GPIO_PIN_13;GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;GPIO_InitStruct.Alternate = GPIO_AF9_FDCAN2;HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);/* FDCAN2 interrupt Init */HAL_NVIC_SetPriority(FDCAN2_IT0_IRQn, 1, 0);HAL_NVIC_EnableIRQ(FDCAN2_IT0_IRQn);/* USER CODE BEGIN FDCAN2_MspInit 1 *//* USER CODE END FDCAN2_MspInit 1 */}
}void HAL_FDCAN_MspDeInit(FDCAN_HandleTypeDef* fdcanHandle)
{if(fdcanHandle->Instance==FDCAN2){/* USER CODE BEGIN FDCAN2_MspDeInit 0 *//* USER CODE END FDCAN2_MspDeInit 0 *//* Peripheral clock disable */__HAL_RCC_FDCAN_CLK_DISABLE();/**FDCAN2 GPIO ConfigurationPB12     ------> FDCAN2_RXPB13     ------> FDCAN2_TX*/HAL_GPIO_DeInit(GPIOB, GPIO_PIN_12|GPIO_PIN_13);/* FDCAN2 interrupt Deinit */HAL_NVIC_DisableIRQ(FDCAN2_IT0_IRQn);/* USER CODE BEGIN FDCAN2_MspDeInit 1 *//* USER CODE END FDCAN2_MspDeInit 1 */}
}

添加

配置接收过滤与中断：

过滤主要有 4 种， FDCAN_FILTER_RANGE、FDCAN_FILTER_MASK、FDCAN_FILTER_DUAL、FDCAN_FILTER_RANGE_NO_EIDM，这里使用 FDCAN_FILTER_MASK 过滤

	FDCAN_FilterTypeDef sFilterConfig;sFilterConfig.IdType       = FDCAN_STANDARD_ID;sFilterConfig.FilterIndex  = 0;sFilterConfig.FilterType   = FDCAN_FILTER_MASK;sFilterConfig.FilterConfig = FDCAN_FILTER_TO_RXFIFO0;sFilterConfig.FilterID1    = 0x111;sFilterConfig.FilterID2    = 0x7F0;  // mask 为1部分需完全匹配HAL_FDCAN_ConfigFilter(&hfdcan2, &sFilterConfig);HAL_FDCAN_ConfigGlobalFilter(&hfdcan2,FDCAN_REJECT, DISABLE, DISABLE, DISABLE);  //设置被滤除掉的消息的处理方式HAL_FDCAN_ConfigRxFifoOverwrite(&hfdcan2, FDCAN_RX_FIFO0, FDCAN_RX_FIFO_BLOCKING);HAL_FDCAN_ActivateNotification(&hfdcan2,FDCAN_IT_RX_FIFO0_NEW_MESSAGE,0);/* set the wartermark of Rx FIFO0 to 1 */HAL_FDCAN_ConfigFifoWatermark(&hfdcan2, FDCAN_CFG_RX_FIFO0, 1);
//	/* Enable wartermark interrupts of Rx FIFO0  */HAL_FDCAN_ActivateNotification(&hfdcan2, FDCAN_IT_RX_FIFO0_WATERMARK, 0);HAL_FDCAN_Start(&hfdcan2);

中断接收

中断接收采用 FDCAN_IT_RX_FIFO0_NEW_MESSAGE 接收，需要同时打开 FDCAN_IT_RX_FIFO0_WATERMARK

struct canfd_frame{uint16_t can_id;uint16_t dlc;uint8_t data[64];
};
void HAL_FDCAN_RxFifo0Callback(FDCAN_HandleTypeDef *hfdcan, uint32_t RxFifo0ITs)
{if(RxFifo0ITs & FDCAN_IT_RX_FIFO0_NEW_MESSAGE){struct canfd_frame* buff;HAL_FDCAN_GetRxMessage(hfdcan, FDCAN_RX_FIFO0, &rxHeader, buff->data);buff->can_id = rxHeader.Identifier;buff->dlc = rxHeader.DataLength >> 16;}
}

发送

发送需要需要注意 BitRateSwitch 需要为 FDCAN_BRS_OFF， DataLength 为高 16 位

	static FDCAN_TxHeaderTypeDef txHeader = {0};txHeader.IdType = FDCAN_STANDARD_ID;txHeader.TxFrameType = FDCAN_DATA_FRAME;txHeader.ErrorStateIndicator = FDCAN_ESI_ACTIVE;txHeader.BitRateSwitch = FDCAN_BRS_OFF;txHeader.FDFormat = FDCAN_FD_CAN; txHeader.TxEventFifoControl = FDCAN_NO_TX_EVENTS;txHeader.MessageMarker = 0;txHeader.Identifier = buff->can_id;txHeader.DataLength = buff->dlc << 16; memcpy(txData, buff->data, sizeof(txData));while (HAL_FDCAN_GetTxFifoFreeLevel(&hfdcan2) == 0){if(hfdcan2.Instance->TXFQS & FDCAN_TXFQS_TFQF){HAL_FDCAN_DeInit(&hfdcan2);MX_FDCAN2_Init();//这里重新初始化 can}}HAL_FDCAN_AddMessageToTxFifoQ(&hfdcan2, &txHeader, txData);

错误中断

错误中断需要开启，用于错误检测与复位 can 通信，在使用中存在因为 can 产生错误，而后不进入中断问题，此时，需要在错误后，复位 can，让其重新配置。

可以在配置时，打开这些错误中断，错误状态中，检测这3个 FDCAN_IR_EP 、FDCAN_IR_EW 、FDCAN_IR_BO 即可；错误回调中检测 FDCAN_IR_PED，其他的暂未发现问题。

HAL_FDCAN_ActivateNotification(&hfdcan2, FDCAN_IT_BUS_OFF | FDCAN_IT_ERROR_WARNING |FDCAN_IT_ERROR_PASSIVE | FDCAN_IT_RESERVED_ADDRESS_ACCESS |FDCAN_IT_DATA_PROTOCOL_ERROR | FDCAN_IT_ARB_PROTOCOL_ERROR |FDCAN_IT_ERROR_LOGGING_OVERFLOW | FDCAN_IT_RAM_ACCESS_FAILURE, 0);void HAL_FDCAN_ErrorCallback(FDCAN_HandleTypeDef *hfdcan)
{if(hfdcan2.ErrorCode & FDCAN_IR_PED){resetCan();}
}void HAL_FDCAN_ErrorStatusCallback(FDCAN_HandleTypeDef *hfdcan, uint32_t ErrorStatusITs)
{if(ErrorStatusITs & (FDCAN_IR_EP | FDCAN_IR_EW | FDCAN_IR_BO)){resetCan();}
}

注

• stm32mp15x 的 DLC 和其他的 st 芯片不一样，在高 16位，使用时注意左右移。

#define FDCAN_DLC_BYTES_0  ((uint32_t)0x00000000U) /*!< 0 bytes data field  */
#define FDCAN_DLC_BYTES_1  ((uint32_t)0x00010000U) /*!< 1 bytes data field  */
#define FDCAN_DLC_BYTES_2  ((uint32_t)0x00020000U) /*!< 2 bytes data field  */
#define FDCAN_DLC_BYTES_3  ((uint32_t)0x00030000U) /*!< 3 bytes data field  */
#define FDCAN_DLC_BYTES_4  ((uint32_t)0x00040000U) /*!< 4 bytes data field  */
#define FDCAN_DLC_BYTES_5  ((uint32_t)0x00050000U) /*!< 5 bytes data field  */
#define FDCAN_DLC_BYTES_6  ((uint32_t)0x00060000U) /*!< 6 bytes data field  */
#define FDCAN_DLC_BYTES_7  ((uint32_t)0x00070000U) /*!< 7 bytes data field  */
#define FDCAN_DLC_BYTES_8  ((uint32_t)0x00080000U) /*!< 8 bytes data field  */
#define FDCAN_DLC_BYTES_12 ((uint32_t)0x00090000U) /*!< 12 bytes data field */
#define FDCAN_DLC_BYTES_16 ((uint32_t)0x000A0000U) /*!< 16 bytes data field */
#define FDCAN_DLC_BYTES_20 ((uint32_t)0x000B0000U) /*!< 20 bytes data field */
#define FDCAN_DLC_BYTES_24 ((uint32_t)0x000C0000U) /*!< 24 bytes data field */
#define FDCAN_DLC_BYTES_32 ((uint32_t)0x000D0000U) /*!< 32 bytes data field */
#define FDCAN_DLC_BYTES_48 ((uint32_t)0x000E0000U) /*!< 48 bytes data field */
#define FDCAN_DLC_BYTES_64 ((uint32_t)0x000F0000U) /*!< 64 bytes data field */

• 短路 can 芯片的 H 和 L 两个差分脚，会触发FDCAN_TXFQS_TFQF，此时会无法正常发送，需要重新初始化 canfd

坑

• 在 linux 下用时，需要手动打开 PLL4R

__HAL_RCC_PLL4CLKOUT_ENABLE(RCC_PLL4_DIVR);

• 发送时，BitRateSwitch 需要配置成 FDCAN_BRS_OFF，不然无法发送

txHeader.BitRateSwitch = FDCAN_BRS_OFF;

• 使用 FDCAN_IT_RX_FIFO0_NEW_MESSAGE 中断时，需要将 FDCAN_IT_RX_FIFO0_WATERMARK 中断也打开，不然只能中断一次
• 在线调试时，需要在板子中运行没有中断的程序，然后再使用调试器，下载有中断的程序，不然程序调试有问题；且只能调试一次，需要重新上下电才能正常，就是说，产生中断后，程序就不能进行中断调试了

参考

https://github.com/STMicroelectronics/STM32CubeH7/blob/master/Projects/STM32H743I-EVAL/Examples/FDCAN/FDCAN_Com_IT/Src/main.c
https://github.com/STMicroelectronics/STM32CubeMP1/blob/master/Projects/STM32MP157C-EV1/Examples/FDCAN/FDCAN_Loopback/Src/main.c
https://club.rt-thread.org/ask/article/f354701c18db97db.html