Unstable USB and SIM connection if upgrade from 7.43


I can successfully work with SL6087 if there is FW 7.43 . If we upgrade it, USB is unstable and SIM card is not recognized. What is the different in new firmwares 7.45,7.46 makes me this trouble?


What is the exact problem you are facing with USB ?


Now I changed interface to UART which has no problems with stability. But my SIM card is not accessible in 7.45 and 7.46 FW. When we downgrade to 7.44 or 7.43 the SIM connectivity is OK. I should note that we use AT+WFM=0,”SIMREMOVE" following AT+CFUN=1 to disable SIM PRESENT pin.


You still haven’t explained what, exactly, you mean by “ustable” here.


USB connection was lost time to time. I change to UART and here is no problem.

Now I see that AT+WFM=1,“SIMREMOVE” does not work correctly from 7.45.
SIMPRES Pin no.10 (SL6087) must be at 1.8V to access SIMcard anyway. Command WFM=1,“SIMREMOVE” only suppress WIND 0 and WIND 1.


If my understanding is not wrong with AT+WFM=1,“SIMREMOVE” you would receive an +WIND :0 indication when SIM is removed and +WIND : 1 indication when the SIM is inserted .So you are saying that this is not working with R 7.45 .


No. I say +WIND message is correctly suppressed by +WFM=0,SIMREMOVE. But hardware state of the pin SIPMRES (pin 10 at SL6087) is never ignored from 7.45. It means SIMPRES pin must be HIGH to keep SIM working independently on SIMREMOVE command.
SIMREMOVE command has no influence on reading this pin from 7.45. As I remember good, this bug was already in some older versions and was described in Release Notes cca 7.42 which I can not find on server now.
SIMREMOVE command should determine if SIMPRES pin is used by SIM holder or not (as described in manual and what was working in 7.43). We make our design without SIMPRES pin and we can not upgrade to 7.45+ because SIM interface is not working if SIMPRES pin is LOW. Am I wrong?
Thanks for comments, best regards…