[Ovmsdev] Cannot reset simcom stuck in PoweringOn state without removing module power

Michael Balzer dexter at expeedo.de
Sun Feb 2 18:07:50 HKT 2020

Craig, Mark, Thomas,

Dimitrie / Thomas just reported a very similar (same?) issue on a EU modem: https://www.openvehicles.com/node/2401

He managed to get a log from the issue, which shows the MUX startup to be broken and remain broken until power down.

Specifically, MUX port 2 (just that one) gets stuck in some error state, which does not resolve by a soft power cycle.
Thomas also found out even a short hard power cycle won't be sufficient to resolve this:

> I found out, when i powered off and 1-2 sec. later on again. the modem got stuck.
> when i power it off and wait 1 minute and then power it on. it will start normal.

His modem firmware version is 35316B12SIM5360E (B12).

@Thomas: there is a B13 available…

> I've found later versions (up to B13) and release notes listed only here:
> https://techship.com/products/simcom-sim5360e-mpcie-sim/
> …but you need an account to access them and must accept an NDA.

If you feel lucky you might try that. But it's also possible this is a hardware flaw in all SIM5360 versions.


Am 05.01.20 um 11:12 schrieb Michael Balzer:
> Craig,
> you'll need log level verbose to see all tx/rx going on (i.e. MUX commands), but debug should be sufficient for the power on sequence.
> You can test setting the PWRKEY manually by "egpio output 0 1". If the simcom driver is now stuck in the power cycle loop and interferes, you should be able to
> stop that by "simcom setstate PoweredOff" or "power simcom off".
> Regards,
> Michael
> Am 05.01.20 um 05:16 schrieb Craig Leres:
>> The simcom on one of my modules wedged today and had some time to poke at it. When I turn on simcom debugging I see "AT" commands once a second:
>>     D (1199981) simcom: tx scmd ch=0 len=4   : AT
>>     D (1200981) simcom: tx scmd ch=0 len=4   : AT
>> but no responses.
>> I wanted to see if I could talk to the simcom via the usb connector on the modem card so I sacrificed a micro usb cable and hacked the molded end off so I
>> could plug it in without detaching the modem board from the main board (see attached).
>> Next I spent a few minutes with a spare module looking for a windows 10 driver. The sim5360 (rar) archive from techship.com didn't work but the windows 8 zip
>> file from here did:
>> https://github.com/botletics/SIM7000-LTE-Shield/tree/master/SIM7000%20Documentation/Drivers
>> I ended up with four com ports (at, nema, diagnostic, and audio) and was able to talk to the spare modem.
>> Then I went out to plug into the simcom in the car. The first thing I noticed was that the blue led on the modem board is not lit and (as expected) I got
>> nothing from the at com port.
>> For completeness I tried rebooting the module but it help.
>> I now believe wedging the simcom involves running the car for a short amount of time. In this particular case I moved the car out of the garage to make room
>> for some work on my other car. An hour later I moved it back. The run time was 1-2 minutes each time. A bit later when I tested Mark's new ios app I noticed
>> that the car was not reporting a location.
>> I looked at the simcom docs a bit and it's too bad the simcom RESET pin isn't connected to a pio pin.
>> It'll be a couple of days before I'll need the gps to work in case there are ideas of what can be done via software to wake up the simcom. I might trying add
>> a simcom command to set PWKEY to an arbitrary state to see if holding it low for more than one second does anything.
>>         Craig 

Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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