Posted on May 12, 2014 at 15:12 Hello everyone.
I'm trying to get USB VCP communication to my STM32F107 working (using USB to communicate via minicom with my µc).
Looking at the example and the STM32_USB_Device_Library of the STM32_USB-Host-Device_Lib_V2.1.0 package, I saw the template but the code doesn't seem to make sense.
usbd_cdc_if_template.c:
/**
* @brief TEMPLATE_DataTx
* CDC received data to be send over USB IN endpoint are managed in
* this function.
* @param Buf: Buffer of data to be sent
* @param Len: Number of data to be sent (in bytes)
* @retval Result of the opeartion: USBD_OK if all operations are OK else USBD_FAIL
*/
static
uint16_t TEMPLATE_DataTx (uint8_t* Buf, uint32_t Len)
{
/* Get the data to be sent */
for
(i = 0; i < Len; i++)
{
/* APP_Rx_Buffer[APP_Rx_ptr_in] = ***_ReceiveData(***); */
}
/* Increment the in pointer */
APP_Rx_ptr_in++;
/* To avoid buffer overflow */
if
(APP_Rx_ptr_in == APP_RX_DATA_SIZE)
{
APP_Rx_ptr_in = 0;
}
return
USBD_OK;
}
So
APP_Rx_ptr_in is incremented
after
the loop? And the first parameter,
Buf, is never touched?
Shouldn't it be more like:
APP_Rx_Buffer[APP_Rx_ptr_in++] = ***_ReceiveData(***);
And there might be more to be found. Just makes me question how reliable the code is. Or maybe I just don't understand the intention of this routine.
Would also be happy about any further resources about using the STM32F1XX's USB CDC capabilities.
Regards,
Ben
PS: Also, please STM, use less convoluted site layouts and create a modern, usable community and not this antiquated one-tiered
90ies forum, where information can hardly be found again.
#stm32 #usb #vcp
