1.配置STM32CubeMX
默认配置
选择虚拟串口通信
设置堆栈大小
2.修改代码
打开usbd_cdc_if.h 添加如下代码
#define USB_REC_LEN 12
extern uint8_t USB_RX_BUF[USB_REC_LEN];
extern uint16_t USB_RX_STA;
void USB_printf(const char *format,...);
打开 usbd_cdc_if.c
uint8_t USB_RX_BUF[USB_REC_LEN];
uint16_t USB_RX_STA=0;
修改以下代码
/**
* @brief Data received over USB OUT endpoint are sent over CDC interface
* through this function.
*
* @note
* This function will issue a NAK packet on any OUT packet received on
* USB endpoint until exiting this function. If you exit this function
* before transfer is complete on CDC interface (ie. using DMA controller)
* it will result in receiving more data while previous ones are still
* not sent.
*
* @param Buf: Buffer of data to be received
* @param Len: Number of data received (in bytes)
* @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
/* USER CODE BEGIN 6 */
if(*Len<USB_REC_LEN)
{
uint16_t i;
USB_RX_STA = *Len;
for(i=0;i<*Len;i++)
{
USB_RX_BUF=Buf;
}
}
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
USBD_CDC_ReceivePacket(&hUsbDeviceFS);
return (USBD_OK);
/* USER CODE END 6 */
}
/**
* @brief CDC_Transmit_FS
* Data to send over USB IN endpoint are sent over CDC interface
* through this function.
* @note
*
*
* @param Buf: Buffer of data to be sent
* @param Len: Number of data to be sent (in bytes)
* @retval USBD_OK if all operations are OK else USBD_FAIL or USBD_BUSY
*/
uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
{
uint8_t result = USBD_OK;
/* USER CODE BEGIN 7 */
uint32_t TimeStart=HAL_GetTick();
USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceFS.pClassData;
// if (hcdc->TxState != 0){
// return USBD_BUSY;
// }
while(hcdc->TxState)
{
if(HAL_GetTick()-TimeStart>10)
return USBD_BUSY;
else
break;
}
USBD_CDC_SetTxBuffer(&hUsbDeviceFS, Buf, Len);
result = USBD_CDC_TransmitPacket(&hUsbDeviceFS);
TimeStart=HAL_GetTick();
while(hcdc->TxState)
{
if(HAL_GetTick()-TimeStart>10)
return USBD_BUSY;
}
/* USER CODE END 7 */
return result;
}
添加函数
#include <stdarg.h>
void USB_printf(const char *format,...)
{
va_list args;
uint32_t length;
va_start(args,format);
length=vsnprintf((char *)UserTxBufferFS,APP_TX_DATA_SIZE,(char *)format,args);
va_end(args);
CDC_Transmit_FS(UserTxBufferFS,length);
}
打开main.c
uint8_t i;
uint8_t USB_RX_BUF_Change[USB_REC_LEN];
while (1)
{
if(USB_RX_STA!=0)
{
//USB_printf("USB_RX:");
//CDC_Transmit_FS(USB_RX_BUF,USB_RX_STA);
for(i=0;i<12;i++)
{
USB_RX_BUF_Change=USB_RX_BUF;
//USB_printf("USB_RX_BUF[%d]=%X\n",i,USB_RX_BUF_Change);
USB_printf("%X ",USB_RX_BUF_Change);
}
//USB_printf("\r\n");
USB_RX_STA=0;
memset(USB_RX_BUF,0,sizeof(USB_RX_BUF));
}
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
数据长度为12
打开串口，接收成功。
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版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
原文链接：https://blog.csdn.net/m0_53197842/article/details/145615284
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