Sim Card Not Inserted problems... | Telit Cinterion IoT Developer Community
May 21, 2016 - 1:00am, 15282 views
Hi all,
I have a custom board with an EHS6. We followed the hardware integration description but when we insert our sim card, the module does not seem to detect it. AT+CPIN? yields "+CME ERROR: Sim Card Not Inserted".
I confirm that the CCIO (Sim card card detect) goes high to 1.8V. However, CCVCC, the Sim card VCC line, is always stuck at 0V.
Is there any configuration I need to do in AT^SCFG or something? Hopefully I'm just missing something obvious.
Thanks,,
Matt
Hello,
This seems to be some hardware problem. There is no AT command for configuration of SIM detection.
The CCIN line is mandatory for SIM detection. The SIM interface is shut down when the SIM card is removed.
Besides that the total cable length between the SMT application interface pads on EHS6 and the pads of the external SIM card holder must not exceed 100mm.
Regards,
Bartłomiej
Hi Bartłomiej
Thanks for your reply. I suspected hardware as well... any idea why the CCVCC is remaining at 0V? I've also tried a different micro sim card.
As a last ditch effort, I've attached a picture of my schematic and the relevant area on the PCB... I wondered if you could just look it over to make sure it's correct. All I do is open up a COM port and type AT+CPIN? and get the ERROR.
If there's no more advice I have to suspect that the EHS6 was somehow damaged.
Thanks,,
Matt
Hello,
The schematic looks OK.
You have written that "CCIO (Sim card card detect) goes high to 1.8V." - I expect that you had in mind CCIN line and there's 1V8 on the module's CCIN pad. If it goes high the interface should be activated. If not maybe there's some mounting problem or other HW problem.
Regards,
Bartłomiej
I do measure 1.8V at the CCIN pin... But never get anything on CCVCC. When should CCVCC go high?
I have a 1.8V sim card inserted. How does the EHS6 know what voltage to put on CCVCC?
Hello,
The module first tries to use 1.8V and if unsuccessful it tries with 3V.
Please try to issue this command "AT^SIND="simtray",2" to check if the module has detected that the SIM tray is inserted. However "+CME ERROR: Sim Card Not Inserted" reply suggests that probably not. But I don't know what SIM interface you are using: with the tray or not.
How about checking with oscilloscope if CCVCC ever goes high for a while after inserting the SIM card. You could also try some other SIM. Still it is the most probable that some HW part is damaged.
You have probably read the module's HW description but how abut this advice - "To avoid possible cross-talk from the CCCLK signal to the CCIO signal be careful that both lines are not placed closely next to each other. A useful approach is using a GND line to shield the CCIO line from the CCCLK line." ?
Regards,
Bartłomiej
I have same problem for bgs5 module :-(
Besides CCVCC you could also check some other lines behaviour (VBATT, CCIN, VCORE) from power up.
Hi Bartlomiej,
Thanks again for giving advice. I took some very interesting oscilloscope pictures. It seems like there is serious noise on the CCCLK line -- no matter how far I zoomed in, I could not get any nice square wave. Can this be explained by lack of isolation between CCIO and CCCLK? I will put some ground shielding between them on my next revision.
Matt
Hello,
I don't think that this is the case here. The clock signal is regular and does not seem to depend on the CCIO line.
How about that maybe there's some problem with capacitors that you have put - maybe there's a wrong capacitor (despite that there was OK on the schematic). You could try to remove the capacitors for test.
Regards,
Bartłomiej
Hi,
Removing the capacitors did not fix the problem. I tried it without the CCRST, CCCLK and CCIO capacitors -- that didn't work -- then I pulled the CCVCC capacitors and that didn't do anything either.
I guess I have to assume that the EHS6 was damaged?
Matt
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