Quectel and Telit issues

[Marc Murphy]

Thank you Paul have not thought it would be linked to the 3V regulator. Will have a probe and also look at powering modem from bench supply to monitor current usage.

> -----Original Message-----
> From: ModemManager-devel <modemmanager-devel-
> bounces at lists.freedesktop.org> On Behalf Of Paul Bartell
> Sent: 05 July 2021 19:44
> To: ModemManager (development) <modemmanager-
> devel at lists.freedesktop.org>
> Subject: Re: Quectel and Telit issues
> 
> I've seen similar messages in the past due to power supply issues.
> 
> If you have an oscilloscope available, probe the main power supply line to
> your modem module and verify that the input voltage does not drop below
> the allowable input voltage.
> 
> You may need to add more bulk capacitance to your board that performs
> well at higher frequencies (ceramic or polymer instead of tantalum) and / or
> increase the output voltage of the DC-DC converter feeding the module (if it's
> not shared with other parts of your board).
> 
> On Mon, Jul 5, 2021 at 11:27 AM Mark Deneen <mdeneen at gmail.com>
> wrote:
> >
> > I use a Telit LE910 on newer kernels (5.10.x) without issue.
> >
> > On Mon, Jul 5, 2021, 09:03 Marc Murphy <marcmltd at marcm.co.uk>
> wrote:
> >>
> >> Hello All
> >>
> >> Been looking at an issue on my embedded device.  Have previously been
> using SierraWireless MC7430 and Huawei module without issues.
> >> I have recently changed to try a Telit 910 and a Quectel EG21-G and get :
> >
> > _______________________________________________
> > ModemManager-devel mailing list
> > ModemManager-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
> _______________________________________________
> ModemManager-devel mailing list
> ModemManager-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel