[BC66] SIM related errors on custom PCB

[brixton]

Thanks for the suggestions.

@herbert.pan-Q

1、I recommend that you weld the pin of the SIM card holder’s pin directly to the pin of the module. This is also allowed and can be used to troubleshoot your circuit design problems.

@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.

@TommyTooter

The holder I was using required the SIM’s chamfered corner to be outward.

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.

@KvX

What is answer for AT+CFUN?

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.