DMA传输CAN的代码

在使用DMA进行CAN（Controller Area Network）通信的代码中，首先你需要配置DMA控制器以正确映射CAN控制器的数据寄存器，并设置传输模式和起始地址。这里是一个简单的示例，假设我们是在STM32这样的微控制器上：

#include "stm32f4xx_hal.h"

// DMA Channel configuration
DMA_HandleTypeDef hdma_can_tx;
hdma_can_tx.Init.Channel = DMA_CHANNEL_1; // Choose the appropriate channel for CAN TX
hdma_can_tx.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_can_tx.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_can_tx.Init.MemInc = DMA_MINC_ENABLE;
hdma_can_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
hdma_can_tx.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;
hdma_can_tx.Init.Mode = DMA_NORMAL;
hdma_can_tx.Init.Priority = DMA_PRIORITY_HIGHEST;
hdma_can_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
hdma_can_tx.Init.Request = DMA_REQUEST_NONE; // Set your specific request here

// Configure the DMA transfer descriptor
DMA_DescriptorTypeDef dma_desc;
dma_desc.Address = &can_buffer[0]; // Buffer where data is stored
dma_desc.DMAreq = DMA_REQUEST_NONE; // Request for the DMA channel
dma_desc.PeriphInc = DMA_PINC_DISABLE;
dma_desc.MemInc = DMA_MINC_ENABLE;
dma_desc.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
dma_desc.MemDataAlignment = DMA_MDATAALIGN_WORD;
dma_desc.ByteCount = CAN_MSG_SIZE; // Message size in bytes
dma_desc.Next = NULL;

// Enable CAN and DMA channels
HAL_CAN_Init(&hcan); // Initialize CAN peripheral
HAL_DMA_Init(&hdma_can_tx); // Initialize DMA
HAL_DMA_Dequeue(&hdma_can_tx, &dma_desc, 1); // Start the first transfer

// Enable DMA transfer request on CAN event (e.g., after a message is sent)
HAL_NVIC_EnableIRQ(DMAx_IRQn); // Replace 'DMAx' with your DMA interrupt number

请注意，这只是一个基础示例，实际应用中还需要根据具体的硬件平台和CAN库进行适当的调整。