Not generating SIM VCC


#1

Hi friends,

I am working with Q2686 module. My problem is that when the module is powered on , the module is not producing the voltage to drive my SIM card(sim vdd). i am using 8 pin sim card connector. I have connected with pc and checked the basic AT commands. The module is responding to the basic commands like AT , which return with OK. the sim interface in my board is same as given in the wavecom q2686 datasheet.

Please help me.

Thank you
Roy


#2

as you’re using the 8-pin sim-connector, i assume you also wired up the sim-present switch right?


#3

yes i have wired it. but the module is not generating sim vdd

thank you


#4

do you have a sim-card in there when you measure?

because after a reset, (or after boot) sim-vcc isn’t generated until the sim-detect is triggered (1V8)


#5

I HAVE SHORTED THE SIMPRESENCE PIN OF THE SIM HOLDER WITH 1v8 SIGNAL . STILL THE SIM CC IS NOT GENERATING.

ROY


#6

*SIM VCC


#7

(also, please, do not shout? )


#8

Hi,

You found a solution?? I’m using Q64 instead of Q2686, but we share that we must make connections of SIM interface on our boards, and I have the same problem, not SIM Vcc. I’m not usign 8 pin SIM socket, instead I have a 6 pin SIM socket. Also I read that Q64 have a pull-up resistor on SIMdet, and High-to-Low transition means that SIM is inserted, and if Low-to-High transition means that SIM is removed.

I think if you short SIMdet to Vcc(1V8) means nothing because pull-up is already giving a High state… and your test means that nothing is happening. Have you tried to short to GND? Maybe it give a Low state and means that is already inserted when start up. With 8 pin SIM socket you will lose the insertion and removal feature, but maybe it work.

I’ll let you know if it work for me…


#9

I shorted SIMdet to ground and it works! SIM Vcc start working and LED start flashing.

Found that Q24 has not a pull-up or pull-down resistor on SiMdet, the Low-to-High transition means SIM inserted and Low-to-High transition means SIM removed (inverted transitions with Q64). But the Product Technical Specification Manual said that “if your not using SIMdet (SIMpres) tie to 2V8”, information that is missing on Q64 (and maybe Q2686) manuals.

Good luck!


#10

Hi,
I have designed some new board using q2686 module with refrenece of evaluation kit.
But its not working …schs of my design is attached in the link https://forum.sierrawireless.com/t/connections/3947/5

I’m geeting all reference volatges i.e V 1.8 and 2.6 voltages on pin 5 and 10. but device is not synched with PC(through M2M studio), sim also not detected …
what may be problem…
pls do help…

regards
raveesh