Using Sim card and UART simultaneously on nRF9160dk

RE: Using Sim card and UART simultaneously on nRF9160dk

Håkon Alseth — Thu, 16 Jan 2020 09:50:51 GMT

[quote user="Jagruti_N2A"]For optimal performance of the nRF9160
radio, it is recommended that only 1.8 V is used." So in my case is it okay set VDD_GPIO to 3V or 3.3V?[/quote]

It is safe to use 3 or 3.3V on VDD_IO. This is a recommendation if you are to use high current and high speed switching (PWM, SPI) on GPIOs physically near the ANT pin, but the impact in a real-life application is minimal.

Kind regards,

Håkon

RE: Using Sim card and UART simultaneously on nRF9160dk

Jagruti — Thu, 16 Jan 2020 09:29:56 GMT

Thank you so much for the information.

But I still have one doubt. In nRF9160dk_user_guide, there is one sentence "The voltage
can be selected to 1.8 V or 3 V using slide switch SW11. For optimal performance of the nRF9160
radio, it is recommended that only 1.8 V is used." So in my case is it okay set VDD_GPIO to 3V or 3.3V?

RE: Using Sim card and UART simultaneously on nRF9160dk

Håkon Alseth — Thu, 16 Jan 2020 09:02:45 GMT

Hi,

The SIM card is powered from the nRF9160, and it is supplied with a 1.8V source regardless of what the VDD_GPIO is set to.

The SIM_* pins are dedicated to SIM communication, and cannot be reconfigured for other purposes.

When you are sending and receiving any type of data over the network (SMS, IP, etc), this is not going through your SIM at all. The SIM is used to authenticate you on the network itself, and after that is done, you send data, like SMS or IP data, using the CPU in the microcontroller.

Sending or receiving data over IP or SMS is therefore not directly coupled with the UART, meaning that you should be able to do both (provided that the CPU is not busy).

Kind regards,

Håkon