Doubts about how nRF9160 works

[Joao Filipe]

Hi Everyone! 

I checked this links https://infocenter.nordicsemi.com/pdf/nRF9160_DK_User_Guide_v0.9.pdf#page=20  and  https://github.com/NordicPlayground/fw-nrfconnect-zephyr/tree/master/boards/arm/nrf52840_pca10090 and I got some questions!
Can you check the questions/observations bellow and say to me if I'm right or wrong and correct me if wrong? I'm sorry in advance if I'm being a little bit "dumb".

So:
1)nRF9160 DK allows that applications to be programmed in 2 ways, at nrf9160 SiP or at nRF52 SoC.

2)nRF52 is used as board controller and Bluetooth/IEEE 802.15.4 network processor.

3)Both nrf9160 SiP and NRF52 SoC have their own firmware. The impression that I got from documentation and https://www.nordicsemi.com/Software-and-tools/Development-Kits/nRF9160-DK/Download#infotabs  is that the nRF91 firmware is specific of nRF91, but the firmware for nRF52(modem firmware) is generic. Like without this modem FW the DK would not work properly or simply not work at all.

4)nRF52 SoC controls CLOCK, FLASH, GPIO, RADIO, RTT, etc.

5)About the nrf9160_pca10090 and nRF5240_pca10090, are the _pca10090 the same? Or is a little bit different because the nRF is different?

6)At https://infocenter.nordicsemi.com/pdf/nRF9160_DK_User_Guide_v0.9.pdf#page=20 it says that nRF52 controls analog switches on DK. But at zephyr\boards\arm\nrf52840_pca10090\doc\index.rst it says that nRF52 SoC has nothing to do about leds, buttons etc...
Is that means that buttons, switches and leds says respect only to nRF9160 and the only interaction from nRF52 SoC with them is to router to on board functionality?

7)If I program the asset_tracker to nRF9160, the nRF52 only has interaction because he is board controller(FLASH, RTT(Segger)?? Or about the code itself has something to do?
Or it will only have interaction if the code has switches, buttons or leds? Or even with that, it has no interaction?
Or it will only have interaction if is an specific application with SW5 is to nRF52.

8)You said that the mqtt_simple sample says respect to nRF9160 SiP. So, if I alter that code to work with buttons, like for example, if I press button 1 it changes to another topic, button 2, it disconnect, something like that, I would be in same only using nRF9160 resources?

Sorry for anything.
With my best

[Martin Lesund]

Hi Joao,

1).

The nRF52 that is on the nRF91DK works as a board controller to route the different signals around the DK.

You can e.g. change the code on the board controller to for example route the UART to the external ports instead of the VCOM.

However, in the LTE Sensor Gateway the HCI UART sample runs on the nRF52 so it can receive BLE data from a Thingy:52 and the nRF91 sends that data again to the nRF Cloud.

The nRF91DK is primarily meant for development on the nRF9160. If you are developing using the nRF52 series I would recommend using the nRF52DKs.

2). see 1)

3).

Now we need to specify a bit. The modem firmware runs on the nRF9160 SiP. 

Notice the figure of the nRF9160 underneath. 

The nRF52 is default used as the board controller on the DK. 

The modem firmware is the LTE-M/NBiOT and GPS stack, which you need to be able to utilize the modem.

Please check out the nRF9160 documentation and the cellular tutorials for more information.

4). 

No, Please check the nRF9160 documentation.

 

5).

 The pca10090 is the name of the nRF91DK. 

another example is that PCA10056 is the name of the nRF52840 DK

6).

Documentation of what signals the board controller routes by default.

Also the default values in the code.

7).

It only routes out the signals as shown in 6).

The only sample where the nrf52 is running another FW than the default Board Controller FW is in the LTE Sensor Gateway.

8).

You do not need to change anything with the nRF52 FW to do that no.

Just implement that in the MQTT application you are running on nrf91.

Best regards,

Martin L.