Question about the sim reset signal

[Alex Wiitamaki]

Hello,

We were wondering under what conditions the SIM will reset. AT commands will give us activity on the SIM_CLK and and SIM_IO lines, we are looking to see activity on the SIM_RST line for hardware test purposes.

Thanks,

Alex Wiitamaki

[Alex Wiitamaki]

Forgot to specify that we are using the nRF9160.

[AndreasF]

Hi Alex.

The LTE modem is responsible for the reset signal as well as the clock signal and I/O serial data, as you can read here.

I think the reset signal is triggered by the modem if there is problems with the SIM card, but I have to check with our development team to be sure.

Best regards,

Andreas

[AndreasF]

Hi again Alex.

I've talked to our development team and unfortunately there is no way to directly control SIM_RST using AT Commands.

It is possible to power of the SIM card using for example AT+CFUN=4, this will make SIM_RST go to '0', and power on the SIM card using AT+CFUN=1. These commands do have other effects in addition to the SIM card interface.

And also as I said in my previous reply, SIM_RST will be used by the modem FW as an error recovery attempt if there is a problem with the SIM card, and the SIM card may also be powered off temporary for power saving reasons during PSM and eDRX periods.

Best regards,

Andreas