Hello,
We hand assembled some prototypes of a sensor with a nrf9160 and they worked well, so we commissioned a small batch assembly of 20 units. These have the same bill of materials and for the critical parts (everything besides non antenna matching passives) it was requested to be the same supplier (Digikey) as the hand assembled prototypes. They have the same part number and hardware revision of SICA-B1.
The new boards are able to program and run firmware just fine all up to connecting with the network (I have updated the modem firmware to 1.3.4). Even testing through the AT Client example with LTE link monitor I am unable to get a connection even after an hour.
I can get the PDN to enable if I manually set the system mode and APN, not sure if that is relevant.
Could it be an antenna connection or matching components issue (since the CSQ is 99, although I don't not know if that is still the case if the modem hasn't made a connection). The same SIM in the hand assembled version connects perfectly fine. The boards are powered by a bench power supply so that is not an issue. The AT+CFUN=1 response is shown below.
*** Booting Zephyr OS build v3.2.99-ncs1 *** The AT host sample started AT+CFUN=1 OK AT+CFUN? +CFUN: 1 OK AT+CGSN=1 +CGSN: "351358811354783" OK AT+CGMI Nordic Semiconductor ASA OK AT+CGMM nRF9160-SICA OK AT+CGMR mfw_nrf9160_1.3.4 OK AT+CEMODE? +CEMODE: 2 OK AT%XCBAND=? %XCBAND: (1,2,3,4,5,8,12,13,18,19,20,25,26,28,66) OK AT+CMEE? +CMEE: 0 OK AT+CMEE=1 OK AT+CNEC? +CNEC: 0 OK AT+CNEC=24 OK AT+CGEREP? +CGEREP: 0,0 OK AT+CGDCONT? OK AT+CGACT? OK AT+CGEREP=1 OK AT+CIND=1,1,1 OK AT+CEREG=5 OK AT+CEREG? +CEREG: 5,90 OK AT%CESQ=1 OK AT+CESQ +CESQ: 99,99,255,255,255,255 OK AT%XSIM=1 OK AT%XSIM? %XSIM: 0,9 OK
One difference I noticed is the markings on the IC, and besides one post on devzone I was unable to find nrf9160s with this style of marking.The marking style was changed and noted around 2020 in this document, but the older style of marking is still different from the old marking style in the document (which I so found plenty examples of online).
The left pictured above is the working hand assembled board chip's marking and the right is the newly received one that doesn't connect to the cell network. The gerbers and everything else is identical. Were chips around 2021 week 14 made with these markings? Any AT commands I can send to gather more information about why it is not connecting?
Regards,
Sawaiz
