nRF9160 low power coex and magpio pin config

[tedhavelka]

Hello Devzone,

With an nRF9160 based project and lowest power, lowest current consumption in mind, is there an explicit I/O pin setting to make via Zephyr API for the nRF9160 pins COEX0, COEX1, COEX2, AUX, MAGPIO0, MAGPIO1 and MAGPIO2?

I have reviewed these pins' descriptions in https://infocenter.nordicsemi.com/pdf/nwp_037.pdf.

It is still unclear to me from this documentation what is best practice for cases where any of these pins are not connected.  We have COEX0 connected to a circuit node, but the other two COEX pins are no connects for us.  MAGPIO lines are tied to ground through weak pull down resistors.  Is it more effective to configure these as Zephyr 2.6.0's GPIO_DISCONNECTED status?  Or configure them as outputs set to electrical low level?

- Ted

[Håkon Alseth]

Hi Ted,

 

If you do not use any of these pins, you can leave them as-is. The modem will take care of their default state to ensure low power.

However, if they are in use, you should follow the recommended handling. Please note this line for the used COEX pins in your design, in chapter 4.16 in the nwp_037 that you linked to:

Therefore, it is mandatory to use external pull-down resistors in the size range of 100 kΩ in the COEX interface.

 

Kind regards,

Håkon