Command entry

Start and end of a command

A potential command is considered to begin when its first character is received. For the serial port this is straightforward; for the USB it is hard or impossible for the CPU to 'see' how the messages are packaged, but the overall effect is similar. In both cases the potential command has been received once the logger sees a termination character; either one of <CR> (0x0D) or <LF> (0x0A). Combinations of the two characters are dealt with as follows:

CODE

>> <CR><LF>
<< Ready:
>> <LF><CR>
<< Ready:
>> <CR><CR>
<< Ready: Ready:
>> <LF><LF>
<< Ready: Ready:

In the first two cases, the second character is considered redundant and is discarded; only one Ready: prompt is sent. For the last two cases, the second character is treated as a second empty command, so it also provokes the logger's prompt, and a total of two prompts are sent (see also the prompt command).

Upper case and lower case

In general, the logger is not sensitive to the case of the input; for example, ID, Id, iD, and id are all acceptable forms for the id command. Any exceptions to this rule are highlighted when necessary. However, when handling logger responses, do not assume that the case of the output will match the case of the input: see also Parsing logger responses.

Common error messages

The received message may or may not form a valid command; errors detectable by the logger will vary from one command to another, but some of the common, general errors include:

E0102 invalid command '<unknown_text>'
E0107 expected argument missing
E0108 invalid argument to command: '<unknown_text>'

See Error messages for a complete list.