As data comes in from the USB, it is placed in a stream buffer by the USB stack. The StreamBuffer function for incoming data can be accessed from GetUsbRxStreamBuff() in Drivers/HandsOnRTOS/VirtualCommDriverMultiTask.c:
StreamBufferHandle_t const * GetUsbRxStreamBuff( void ){ return &vcom_rxStream;}
This function returns a constant pointer to StreamBufferHandle_t. This is done so the calling code can access the stream buffer directly, but isn't able to change the pointer's value.
The protocol itself is a strictly binary stream that starts with 0x02 and ends with a CRC-32 checksum, transmitted in little endian byte order:
There ...
