Spiffy Prog v0.1.
Next, the programmer sends the command prompt, a single greater than (">") character. At this prompt, a single character for a command is entered by the user. After the command has run, the programmer will return to the command prompt for further instructions. Some commands require additional characters to be entered following the command character and will prevent the programmer from returning to the prompt until all the expected characters have been entered.
If a command ends in error, the programmer will send an error code before the next command prompt and light the error LED. Error codes begin with an exclamation point ("!") followed by at least one character describing the error. After an error, the programmer will refuse to accept any further commands that involve communication to the target PIC until the user acknowledges the error. This was done because the way a program, in the form of a hex file, is sent to the programmer from a terminal program may not offer a way to stop sending the hex file if an error occurs before the whole hex file is sent.