Hands-On RTOS with Microcontrollers

Public functions

VirtualComDriver.c  currently has three publicly available functions: 

• TransmitUsbDataLossy
• TransmitUsbData 
• VirtualCommInit

TransmitUsbDataLossy is simply a wrapper around a stream buffer function call. It uses an ISR-safe variant, which is guaranteed not to block (but may also not copy all data into the buffer). The number of bytes copied into the buffer is returned. In this case, it is up to the calling code to determine whether or not to finish copying data into the buffer:

int32_t TransmitUsbDataLossy(uint8_t const* Buff, uint16_t Len){  int32_t numBytesCopied = xStreamBufferSendFromISR( txStream, Buff, Len,                                                                   NULL);  return numBytesCopied;}

TransmitUsbData provides a bit more convenience. It will block up to two ticks ...