sim hot swap problem with Telit GE910-QUAD

[Aleksander Morgado]

On Thu, Jul 20, 2017 at 5:42 PM, Tim Small <tim at seoss.co.uk> wrote:
> On 20/07/17 09:09, Carlo Lobrano wrote:
>>
>>> I think that the commands which mm issue causes it to close and reopen
>>> the SIM and this takes longer than mm is giving it.  How should I work
>>> around this?
>>
>> This modem has an unsolicited signal (QSS) that shows the presence and
>> status of the SIM.
>
> I think the problem may be connected to the issuing of the AT+CSIM=1
> command to directly interact with the SIM card after "AT#QSS=1" mode is
> enabled? - from the AT Commands Reference Guide for Telit modems, "Rev.
> 24 - 2016-09-07", page 176:
>
> "After the locking of the SIM-ME interface (AT+CSIM=1) the SIM will be
> accessible only by AT+CSIM commands (#QSS: 0)."
>
> http://www.telit.com/fileadmin/user_upload/products/Downloads/2G/Telit_AT_Commands_Reference_Guide_r24.pdf
>
> This is consistent with this behaviour I see on the terminal:
>
> --> AT+CSIM=1
> <-- OK
> <--
> <-- #QSS: 0
> --> AT+CSIM=10,0020000100
> <-- +CSIM: 4,"63C3"
> <--
> <-- OK
> <--
> --> AT+CSIM=0
> <-- OK
> <--
> <--#QSS: 1
>
>
> ... if you issue a +CSIM=1 command and then don't do anything, the lock
> command (+CSIM=1) command eventually times out, and at that point you
> get an unsolicited '#QSS: 1'.
>

Does this mean we should actually be ignoring any #QSS indication
while we are in between the +CSIM=1 and +CSIM=0 commands?


> Here's a more relevant extract from the debug log:
>
> https://gist.github.com/tim-seoss/acd3624cfbe46a28faebb29a66045432
>
> in particular around line 82, 83 it looks like there's some sort of race
> going on with the pin lock checking and init command streams getting
> issued at the same time and eating each other's responses?
>

ModemManager[15621]: <debug> (ttyUSB0): --> 'AT+CSIM=10,002C000100<CR>'
ModemManager[15621]: <debug> (ttyUSB0): --> 'ATE0<CR>'
ModemManager[15621]: <debug> (ttyUSB0): <-- '<CR>'
ModemManager[15621]: <debug> (ttyUSB0): <-- '<LF>+CSIM: 4,"63C3'
ModemManager[15621]: <debug> (ttyUSB0): <-- '"<CR><LF><CR>'

The AT+CSIM= command there timed out (it took longer than we expected
it to take, a pity that these logs don't have timestamp), and then we
issued ATE0, and we got the response of the previous AT+CSIM command
back there. For this one maybe we should set a longer timeout.

-- 
Aleksander
https://aleksander.es