SPC Version 0.9.5
The SerialOutCount returns the number of characters waiting in an output FIFO send queue of 255 entries.
Characters from the output FIFO are transferred to the host PC at approximately 10,000 per second. If the program is generating characters at a rate greater than this, the output FIFO will start to fill up. This state can be checked by the program by comparing the count with SERIAL_BUFFER_SIZE. In the event that this check is not performed, no data will be lost since the program will stall waiting for space to become available in the FIFO.