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nrf9160 ensure COEX1 is input/floating

tpg

Hi,

We use SDK 2.5.2 on a nrf9160. And have a hardware issue due to a too late update with the first boards. The GNSS LNA enable is wrongly connected to COEX1.

COEX0 is not accessible, but COEX2. A quick possible fix would be to connect COEX2 to COEX1, or alternatively some constant power.

Can we consider COEX1 to be floating/input as default?

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.?

When PPS is disabled in a newer SDK, can we consider the pin floating?

Best,

Thomas

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    Hi Thomas,

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

    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.

    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.?

    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

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  • 0

    Hi Thomas,

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

    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.

    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.?

    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

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