Programming/Debugging nRF9160 SiP on custom board

[bojan]

Hello, guys,

We are designing our custom board that contains nRF9160 SiP.

I would like to ask some questions here concerning programming/debugging nRF9160 SiP on the custom board.

We know it is possible to use nRF9160-DK as a programmer

1. Is this all we need for programming and debugging nRF9160 SiP on our custom board? Do we need to include a nRESET pin as well?
2. Can we update the LTE modem as well with the above approach?
3. Do we need some USB/UART converter (that supports 1.8V voltage level because our GPIO level on nRF9160 will be 1.8V) for being able to benefit from LTE Link Monitor and send AT Commands to the modem?
4. Is there any advantage of using JLink Base programmer/debugger over nRF9160-DK?

Thanks in advance for your time and efforts.

Cheers,

Bojan.

[JONATHAN LL]

Hi Bojan,

The picture is correct. 

Is this all we need for programming and debugging nRF9160 SiP on our custom board? Do we need to include a nRESET pin as well?

 It is not a must, but can be nice to have.

Can we update the LTE modem as well with the above approach?

Yes 

Do we need some USB/UART converter (that supports 1.8V voltage level because our GPIO level on nRF9160 will be 1.8V) for being able to benefit from LTE Link Monitor and send AT Commands to the modem?

Yes, for a custom board if you want to use a serial interface to talk to the nrf9160 from a pc (such as with LTE Link Monitor) then that is the case, you can use either a onboard USB bridge as it is done on the DK's or USB to serial adapter, example link here. 

Is there any advantage of using JLink Base programmer/debugger over nRF9160-DK?

In short: Using a dedicated debugger/programmer instead of the nrf9160DK does provide some benefits but for developing and testing the nrf9160 DK is ok.

The nrf9160 DK provides the J-link OB it does have some limitations compared to a fully featured expensive J-link but do you relay need the features. If you want to program and debug the DK's are sufficient most of the time as it has the same features at J-link BASE.  

Model overview for J-link products if you want to dive in and compare some products.


Check out this case: https://devzone.nordicsemi.com/f/nordic-q-a/56112/nrf9160-custom-pcb-programming---using-nrf91dk 

Here is some more dokumetaion: https://infocenter.nordicsemi.com/topic/ug_nrf91_dk/UG/nrf91_DK/ext_programming_support.html?cp=2_0_5_4_9_0


Regards,
Jonathan

[bojan]

Hey, JONATHAN LL!

Thank you very much for your thorough explanations!

Few more questions... On Thingy:91 board we access nRF9160 through USB<->nRF52840 UART <-> nRF9160 UART path.

- Do we need to include Hardware Flow Control pins (RTS, CTS) of the UART port on our custom board?

- Is it recommended to use the same GPIOs of nRF9160 for UART connection in order to benefit from LTE Link Monitor?

Regards,

Bojan.

[JONATHAN LL]

Hi Bojan,

bojan said:

Do we need to include Hardware Flow Control pins (RTS, CTS) of the UART port on our custom board?

 Flow Control is a option, and in LTE Link monitor there is a box you can check or un-check to enable/disable.


Here is a link to the documentation on suing without flow control

 

bojan said:

Is it recommended to use the same GPIOs of nRF9160 for UART connection in order to benefit from LTE Link Monitor?

 Anny general purpose I/O can be used as as UART, it is easier to test/import examples from NCS when the pin configuration is similar to that of the DK. there will be less to change in the board configuration or overlay file if you all ready use the same pins. But for LTE Link Monitor it wont matter as it sees wat COM port it can connect to.

Link to nrf9160 SiP pin map: https://infocenter.nordicsemi.com/topic/ps_nrf9160/pin.html?cp=2_0_0_9_0_0#reference_hyx_mmw_pv 


Link to GPIO interface on the nrf9160DK and COM port documentation.

Regards,
Jonathan

[bojan]

This is what I call great support!

Thank you very much for all your efforts, JONATHAN LL!

[bojan]

Hey, JONATHAN LL.

I have a second thought concerning this diagram:

There is no sense to me to use NRF_VDD+VTG from the nRF9160-DK to supply our custom board!?1.8V is not enough for supplying nRF9160.

It is OK to set SW11 to 1.8V because GPIO voltage on our custom board is 1.8V. However, we are gonna supply our custom board with external power supply from LiPo batery and, consequently, only GND, SWDIO, SWDCLK, nRESET pins would be enough.

Am I missing something here?

Regards,

Bojan.

[JONATHAN LL]

Hi Bojan,

SW11 set to 1.8V is perfectly fine when both boards are powered externally. 

 

bojan said:

only GND, SWDIO, SWDCLK, nRESET pins would be enough.

 yes

Regards,
Jonathan