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c#parsinggsmat-command.net-micro-framework

Howto properly parse response data received from GSM module?

I'm looking for some guidelines how to properly parse response data received from GSM module. I'm using uBlox SARA-G350. Documentation states:

Information responses:
<CR><LF><text><CR><LF>

Result codes:
<CR><LF><verbose code><CR><LF>

If the command line is successfully performed, the string "OK" (<CR><LF>OK<CR><LF>)
is sent, otherwise "ERROR".

It might looks everything simple. We should read each sentence from <CR><LF> to <CR><LF> but...

  • data may become in chunks
  • response may contains doubled <CR><LF>OK<CR><LF> (see example below)

Example - sms message sent to gsm module:

"Hi. Is IT
OK
"

After CMGL module respond (this is how end of sequence of returned data might looks like):

Hi. Is IT<CR><LF>
OK<CR><LF>
<CR><LF>
OK<CR><LF>

As you can see we have doubled <CR><LF>OK<CR><LF>.

How do I know that I have whole sentence and should stop reading data from module and do parsing received data?

How AT parser should behave in situation like this?

Where I can find some guidelines how to properly parse incoming response data from gsm module?

Solution

  • I found it. My bad assumption was that sms message can contain CrLf within. This is not true (at least for uBlox SARA-G350). All CrLf within some text received from module are replaced to Lf.

    Thanks to that I can know that end of sentence will be when one of the next combinations arrives:

    • <CR><LF>OK<CR><LF>
    • <CR><LF>ERROR<CR><LF>
    • <CR><LF> >

    The last one is prompt sign for sms sending command.