nrf9160 ensure COEX1 is input/floating

RE: nrf9160 ensure COEX1 is input/floating

Charlie — Fri, 23 Aug 2024 06:43:34 GMT

Hi Thomas,

In the document, we only have the following description: When the LTE modem is not active, the COEX interface floats.

The pin COEX1 floating/low state when it is disabled while modem is active is not clear. I will request a measurement in the lab to confirm.

I will update to you once this is done.

Best regards,

Charlie

RE: nrf9160 ensure COEX1 is input/floating

tpg — Wed, 21 Aug 2024 12:13:56 GMT

Hi,

so to clarify, after "nrf_modem_gnss_1pps_disenable" is the pin driving the output to 0, or floating?

RE: nrf9160 ensure COEX1 is input/floating

Charlie — Wed, 21 Aug 2024 12:11:51 GMT

Hi Thomas,

[quote user=""]Can we consider COEX1 to be floating/input as default?[/quote][quote user=""]When PPS is disabled in a newer SDK, can we consider the pin floating?[/quote]

COEX pins all act as output pin. Accoding to COEX (nordicsemi.com):

To control the COEX interface, the LTE modem must be active. When the LTE modem is not active, the COEX interface floats. Therefore, it is mandatory to use external pull-down resistors in the size range of 100 kΩ in the COEX interface.

[quote user=""]

It seems a bit unclear to me, if it always outputs PPS? Is PPS actually implemented?

Some parts of the documentation say it 'can' output PPS, so we can disable it?

Some part refer to the SDK for controlling it, seems with 2.6.99 there is some functionality to disable it. But, what would be the default status with SDK 2.5.?

[/quote]

This 1PPS feature is available no later than NCS v2.5.0, you can disable it with nrf_modem_gnss_1pps_disenable. It is disabled by default, since you need to enable it with nrf_modem_gnss_1pps_enable with some prerequests specified in the link.

Best regards,

Charlie