[Ovmsdev] Cannot reset simcom stuck in PoweringOn state without removing module power
Craig Leres
leres at xse.com
Mon Nov 18 07:14:03 HKT 2019
On 2019-11-17 13:29, Michael Balzer wrote:
> Craig,
>
> Am 17.11.19 um 19:31 schrieb Craig Leres:
>> On 2019-11-17 04:11, Michael Balzer wrote:
>>> I also saw this & can also reproduce this on my workbench.
>> What is the method to induce the problem?
>
> No method. If the theory is right it depends on a combination of random
> circumstances if the MDM_EN signal is long enough for the modem to
> recognize.
I guess I was hoping for a way to wedge the modem so I could be sure if
the resistor works.
> I think something in the range 130-150K should work. That should put the
> base to ~0.5-0.6V for low and to ~1.0-1.2V for high. That's either not
> fully switched off on low or not fully saturated on high, but should be
> sufficient for the modem.
Not 100% sure I have time left this weekend but when I try this I'll try
to grab some traces with my scope. Also my collection of smd resistors
is modest so I'll have to use 1/8w axial to test.
Craig
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