Can not connect to NB-IoT network with new shipping NRF9160 SiP?

[xuan0802]

Hi Nordic team,

I just purchased a row of new nrf9160 SiPs for our IoT products. We are testing with new made cuicuits.

We use the same circuit schematic that worked with previous nrf9160s but small layout size.

We tried to connect to NB-IoT network, but it takes long time without any successful connections. 

I enable AT command "AT+CEREG=5" to receive any reject causes but I could not figure out the clear cause.

For SIM card and antenna, we tested the antenna and SIM with our previous circuit and it connected.

Could Nordic team can help us to figure out the problem ? 

[xuan0802]

[ketiljo]

Is the design identical except for the new nRF9160 modules?

[xuan0802]

Actually, in this version, because we want to make the product smaller. Some pins are open (not connect to anything in version 1) are connected to ground in this version. Those pins are 113, 111, 106. If you need our schematic or layout, I can send you via private messages.

[xuan0802]

We tried to disconnect those pins and connect again to the network.

It can connect again. It seems that these reserved pins deserve the higher warnings (must not connect)

[ketiljo]

Pins 104 to 127 are clearly marked in the pin assignment list as do not connect. Some of them are internal test pins so grounding these can give all sorts of errors.