[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.


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