Few Questions on nRF9160: Thingy:91 and Dev Board

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

geeta — Fri, 26 Jun 2020 12:07:25 GMT

please provide some clarity on how to connect an external antenna to thingy 91 module

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Lakshminarayana K N — Fri, 13 Mar 2020 13:51:37 GMT

Okay.

Thank you.

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Håkon Alseth — Fri, 13 Mar 2020 11:02:43 GMT

Hi,

[quote user="Lakshminarayana K N "]One question on Fractus antenna though TRIO mXTEND has 2 ports (which can be used for GNSS and NB-IoT/CAT-M) May I know the reason why only single port being used?[/quote]

I checked this with the HW designer, and Fractus did the implementation around the antenna. It could be just a coincident, but I'd recommend asking Fractus to hear if they can comment.

Kind regards,

Håkon

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Lakshminarayana K N — Thu, 12 Mar 2020 13:28:47 GMT

Hi,

One question on Fractus antenna though TRIO mXTEND has 2 ports (which can be used for GNSS and NB-IoT/CAT-M) May I know the reason why only single port being used?

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Håkon Alseth — Thu, 27 Feb 2020 15:34:03 GMT

The point of these switches are to allow external antenna or the use of on-board antenna.

Note that you are looking at an old version of the DK, where the latest is v0.10.2: https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF9160-DK/Download

Kind regards,

Håkon

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Lakshminarayana K N — Thu, 27 Feb 2020 13:37:35 GMT

Hi,

Thanks for the inputs.

I need one clarification for this:

" If we're using Separate external antenna for GPS and LTE CAT-M1/NB1 what's the use of Switch(U33 and U34) we can directly connect to the Antenna Feed point to the Module's GPS Feed point(with / Without LNA followed by matching nw ) right?

https://www.nordicsemi.com/-/media/Software-and-other-downloads/Dev-Kits/nRF9160-DK/pca10090_schematic_and_pcb_rev085.pdf "

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Håkon Alseth — Thu, 27 Feb 2020 13:34:03 GMT

Hi,

[quote user="Lakshminarayana K N "]Usually module's have inbuilt LNA right? In this case it's not right?[/quote]

An external LNA is required with the nRF9160.

[quote user="Lakshminarayana K N "]About the LTE Network sleep mode mainly PSM and eDRX mode. In case of eDRX mode, what's the maximum duration it can be in saving mode? and also Is there way where we can completely turn off LTE part(not PSM) and only main CPU and GPS part?[/quote]

For the sleep periods, please see this post: https://devzone.nordicsemi.com/f/nordic-q-a/48027/edrx-mode-psm-mode-sleep-mode-standby-mode-active-mode-power-consumption

Note that you can ask for a given interval, but it is the network that sets this. This means that you cannot expect to get exactly the timing parameters that you ask for.

As for turning off and on the modem, that is done using AT+CFUN: https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/cfun_set.html?cp=2_1_3_0_0

[quote user="Lakshminarayana K N "]In case of Bottom Layer, For the RF Transmission line reference plane is L2 or L3?[/quote]

The transmission line has a GND reference to the closest layer. Note the cut-out (keep out area) underneath the components around the U2 device.

Kind regards,

Håkon

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Lakshminarayana K N — Wed, 26 Feb 2020 14:36:21 GMT

Hi,

Thanks for your reply.

"Yes, an LNA is required." Usually module's have inbuilt LNA right? In this case it's not right?

" No, if the application you develop sleep in a very long period, that should be fine. Are you thinking of eDRX or PSM periods (ie: LTE network sleep periods), or the sleep period local to the CPU? " - About the LTE Network sleep mode mainly PSM and eDRX mode. In case of eDRX mode, what's the maximum duration it can be in saving mode? and also Is there way where we can completely turn off LTE part(not PSM) and only main CPU and GPS part?

" The main ground plane is at inner layer 1. So Signal, GND, Signal and ground, Signal. Power is mainly routed at the bottom layer. " Yea the reason because I do see RF Layout is done in both Top and Bottom Layer.

In case of Bottom Layer, For the RF Transmission line reference plane is L2 or L3?

Thanks.

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Håkon Alseth — Wed, 26 Feb 2020 11:46:41 GMT

Hi,

[quote user=""]If we turn on GPS again immediate after sending the GPS Fix data(meaning Turn off LTE and Turn ON GPS) Will it take again 30 seconds to get the GPS Fix data Or it'll be quicker?[/quote]

It has the almanac and ephemeris at this point. Next fix will be faster.

[quote user=""]Is the LNA for GPS required?[/quote]

Yes, an LNA is required.

[quote user=""]Could you please give me example of COEX2 (pin 91)?[/quote]

You should use COEX0. here’s the AT command in C: https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/samples/nrf9160/gps/src/main.c#L30

[quote user=""]Are there any limitation on Max duration of sleep mode on nRF9160?[/quote]

No, if the application you develop sleep in a very long period, that should be fine. Are you thinking of eDRX or PSM periods (ie: LTE network sleep periods), or the sleep period local to the CPU?

[quote user=""]May I know the Layer stack up details of Thingy:91?(Signal,GND,GND Signal OR Signal,GND,PWR,Signal?)[/quote]

The HW design files can be downloaded from https://www.nordicsemi.com/Software-and-tools/Prototyping-platforms/Nordic-Thingy-91/Download#infotabs

The main ground plane is at inner layer 1. So Signal, GND, Signal and ground, Signal. Power is mainly routed at the bottom layer.

Kind regards,

Håkon

RE: Few Questions on nRF9160: Thingy:91 and Dev Board

Lakshminarayana K N — Wed, 26 Feb 2020 03:55:42 GMT

Hi,

Any updates on this?