[BC66] SIM related errors on custom PCB

Thanks for the suggestions.

@herbert.pan-Q , I haven’t tried that yet because I don’t have such an external SIM connector. But I’ll see if I can get one.

I noticed that I was doing this wrong too, thanks for the suggestion! I’ve changed it around now, but it hasn’t made much difference unfortunately.

CFUN = 1. See logs.

what is CFUN value?
AT+CFUN?

 +CFUN: 1
 
 OK
 

USIM card identification - AT+QCCID
AT+QCCID

 +CME ERROR: 772
 

USIM card identification - AT+QCCID
AT+QCCID

 +CME ERROR: 772
 
Is a PIN needed for the SIM card? AT+CPIN?
AT+CPIN?

 +CME ERROR: 772
 

Is a PIN needed for the SIM card? AT+CPIN?
AT+CPIN?

 +CME ERROR: 772
 


Error 772 means that the USIM is powered down according to the manual. When I measure the voltage of SIM_VDD I measure 0 V. Strange behaviour. In this post it is explained that the voltage drops to 0 V after an initial startup sequence.