nRF9160 with nRF5340

[JordanK]

I'd like to design a board that includes:

• nRF5340 (Bluetooth, NFC, Zigbee, etc.)
• nRF9160 (LTE-M)
• Qorvo DW3110 (UWB)
• Antennas for each
• Coin battery for power

I'd like to program the application on the nRF5340, and have the nRF9160 and DW3110 slaved to it. In order to conserve power, I'd like to entirely disable the Cortex processor in the nRF9160 if possible, so I have a couple questions:

1. Is it possible to disable the application processor in the nRF9160, while allowing the nRF5340's processor to control the nRF9160's LTE-M functionality?
2. If not, is there any way to set this up so that only the nRF5340 needs to be programmed, and we don't need to program both chips?

Unrelated, but how does power consumption compare between the nRF5340 and the nRF52840? I would have thought the nRF5340 had higher consumption since it has an additional 128MHz Cortex, but according to the online power profiler, it's actually substantially less (76 µA average for the nRF5340 vs. 93 µA average for the nRF52840). Is this expected, and if so, how is that possible when it has 3x the processing power?

Thanks!

[Marte Myrvold]

Hi,

Is it possible to disable the application processor in the nRF9160, while allowing the nRF5340's processor to control the nRF9160's LTE-M functionality?

This is not possible. An application must run on the nRF9160 to interact with the modem. This can be a simple application that only communicates with the modem and sends/receives AT commands.

If not, is there any way to set this up so that only the nRF5340 needs to be programmed, and we don't need to program both chips?

You will need to program both chips initially. If you program a bootloader on the nRF9160, you can send firmware updates to it from the nRF5340, for example, over UART.

Unrelated, but how does power consumption compare between the nRF5340 and the nRF52840?

I do not know which settings you configured when testing, but if you look at the default settings, you see that the idle current of the nRF5340 is larger than on the nRF52840, but the current consumption of the Bluetooth LE event is lower.

nRF5340:

nRF52840:

You can find information about current consumption and numbers for typical current consumption in the specifications: nRF5340 - Current consumption and nRF52840 - Current consumption. You will find that the nRF5340 has lower TX/RX current consumption than the nRF52840.

If you want to use the nRF5340 for the radio (Bluetooth LE or IEEE 802.15.4), I recommend running the application on the nRF9160 and only the radio driver/controller on the other chip. In that case, you can use a smaller chip such as the nRF52810 and run something like the Bluetooth: HCI RPMsg sample or the nRF IEEE 802.15.4: Serialization RPMsg sample. Once again, both chips will need to be programmed separately initially, and then you can use a bootloader on the nRF52810 for firmware updates. 
For the firmware update, you can look at an example made by a colleague of mine: https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples/client_smp/smp_client_uart. 

Best regards,

Marte

[JordanK]

Thanks Marte.

Are there any chips available to do it the other way around (nRF9160 as the master, with some Bluetooth/NFC front-end slaved to it)?

For example, would it be possible to use an nRF9160 with a nRF21540?

Or is there any other chip/module that offers BLE and NFC functionality, without also having an on-board processor?

[Kenneth]

Hello,

The nRF21540 is a pure front-end module to increase output power, so it can't support BLE stand-alone. To support BLE you need to connect an nRF52-variant to the nRF9160. The nRF52 need for instance to run the BLE:HCI low power UART to be controlled from the nRF9160. 

We have an example in nRF Connect SDK where the nRF9160 can control the nRF52840 over the HCI:
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/nrf9160/lte_ble_gateway/README.html

Best regards,
Kenneth