Buffer pollution turns some get commands to set

[edco]

Issuing the following sequence of commands results in a motion downsampling query turning into a set:

• MLC0.5
• MCD

The issue is that once a sentinel character is found, the buffer is passed to run as-is:

Arduino-FOC/src/communication/Commander.cpp

Lines 33 to 43 in 395b6cd

	// a string to hold incoming data
	while (serial.available()) {
	// get the new byte:
	int ch = serial.read();
	received_chars[rec_cnt++] = (char)ch;
	// end of user input
	if(echo)
	print((char)ch);
	if (isSentinel(ch)) {
	// execute the user command
	run(received_chars);

Later atof reads past the sentinel and picks up the trailing 5 in the buffer, and the downsampling is set to 5. The least invasive solution might be to null out the character after the sentinel (if we're not at the end of the buffer).