output_float and low signal input?

[Ttelmah]

You should consider adding an input protection device though.
Relatively large pull-up, and an otherwise undriven pin, is 'asking for
trouble'....

[hmmpic]

I now compared the reset design from QUECTEL, Telit, and Simcom. QUECTEL have the best description.
A FET will be just fine, some suggest a 10nF from the pin to ground also.

I think the pin is interfaced to a ARM cpu running 1,8V with some pullup to the 1,8V, but i don't want to rip one module apart to look:-)

[newguy]

[hmmpic]

[temtronic]

Two ways that destroyed my remote energy control panels,3.5 decades ago(prePIC)..

1) employees putting baggies of snow on the panels. Clever really, panel is cold, IR units run, shop is T shirt temperature.Fine until snow melts, drips into panel, bzzzzap!. Remotely isolated that panel, called company, replace panel, BILLED them.

2) 'somehow' a forklift operator managed to 'skewer' a panel by the huge,wide doorway. The owner understood our free lifetime warranty wouldn't apply.

[Ttelmah]

Other one is service engineers putting batteries back in backwards....

[newguy]

- New prototype being left on the tire of a zoom boom (think forklift with an arm), and then being crushed. Crushed prototype sheepishly dropped on my desk and asked if I can fix it.
- Junior employee, holding 4 pin Molex Mini-Fit Jr plug, seeing both 4 and 6 pin Molex Mini-Fit Jr 6 pin receptacles, tried (correctly) to insert it into the 4 pin receptacle. Did not get the expected result once this was achieved, so tried (and succeeded) in plugging the 4 pin jack into the 6 pin receptacle. This instantly fried not only the special USB - based dongle attached to their computer and their computer itself. Then both original junior employee and a second junior employee proceeded to repeat the exercise with a second USB dongle and a second computer. I was honestly somewhat impressed with their resolve, but not their astonishing stupidity.
- Seasoned engineer consulted the schematic of the DUT on their desk and still somehow managed to connect an external 24Vdc supply directly to their USB dongle's 5V sourced from their motherboard. Results were both instantaneous and spectacular.
- Contract PCB manufacturer ignored the drawings and exclusion list regarding what NOT to coat with conformal coat. Dipped all 300 assemblies in a silicone-based conformal compound.

I have soooo many more.

[Ttelmah]

Yes,
I'm afraid the 'limits of stupidity' are remarkably large at times.
The 4pin/6pin one is particularly familiar.
Designs with very carefully chosen 'different plugs', so it is impossible
to get the connections wrong, yet things that are different sizes and
even different shapes are put into one another...

[temtronic]

Some 'genius' engineer designed the Radio Shack COCO. LONG screws to mount the KBD into the case, SHORT screws to assemble the case.
Yes, if you used the long screws(even one..) to fasten the KBD to the top case..oopsy, shiny SHARP pointy thing 'magically' appeared.
We always had 6 top cases and a supply of SHORT screws on hand
sigh I miss the good old days...

[hmmpic]

You are so lucky to have a permanent job