Programming a custom board with an NRF52840 dev kit

[ryerye120]

Hi,

I've made my own PCB with an nrf52840. Right now I'm hoping to test out the bluetooth and measure my board's power consumption - the only problem is that I can't reliably program the microcontroller! A long time ago I was able to program this device with ble_app_blinky so I know the bluetooth works - unfortunately, right now I keep running into JLink errors. The specific setup/issues are listed below:

Right now I'm trying to program my custom board/NRF with 2 example projects: blinky and ble_app_blinky. To do so, I've setup the boards as in the diagram below:

I am powering my custom board with an external supply set to 3.3V (the current limit is set to 3A so we should have more than enough juice) and the dev kit is "powered on" and plugged into my laptop via the uart/usb programming port (the left most usb port on the diagram). With this setup I can reliably program my custom board with the normal blinky program. Unfortunately, when I try to build&debug on my board with ble_app_blinky I get the following error:

Preparing target for download
Executing Reset script TargetInterface.resetAndStop()
Reset: Halt core after reset via DEMCR.VC_CORERESET.
Reset: Reset device via AIRCR.SYSRESETREQ.
Downloading ‘s140_nrf52_7.0.1_softdevice.hex’ to J-Link
Programming 2.7 KB of addresses 00000000 — 00000aff
Programming 149.3 KB of addresses 00001000 — 00026597
Failed to download application.
Error during program/erase phase.
Please check J-Link and target connection.
Download failed

sometimes when I "build & run" directly I get a slightly different error:

Reset: Halt core after reset via DEMCR.VC_CORERESET.
Reset: Reset device via AIRCR.SYSRESETREQ.
Downloading ‘s140_nrf52_7.0.1_softdevice.hex’ to J-Link
Programming 2.7 KB of addresses 00000000 — 00000aff
Programming 149.3 KB of addresses 00001000 — 00026597
J-Link: Flash download: Bank 0 @ 0x00000000: 2 ranges affected (4096 bytes)
J-Link: Flash download: Total: 0.652s (Prepare: 0.172s, Compare: 0.027s, Erase: 0.170s, Program & Verify: 0.106s, Restore: 0.175s)
J-Link: Flash download: Program & Verify speed: 37 KiB/s
Failed to download application.
Error during program/erase phase.
Please check J-Link and target connection.
Download failed

I'm using the latest version of the sdk (v17) and s140. To program my board I'm using SES. I have done all my development so far with the nrf52840 dk (PCA10056) and I figured I could use the same example files. Do I have to change the starting/stopping memory locations for programming? If not, does anyone have any suggestions for further log/debug steps I can proceed with?

I beseech the Nordic (company) gods.

Thank you,

Ryan

[ryerye120]

Hi Jonathan,

JONATHAN LL said:

Now for the roadblock you have, we can continue discussing this here i think. I can do a review of the schematic and board layout files, see if i see any things that could be a issue. If you dont want to share design public i can make this ticket private, or you can just make a new ticket that is private and refer to this ticket in the new review ticket. 

I don't mind posting the schematics here!

Firstly, when I plug my boards into the nrf connect programmer, I can only see the dev kit (that I'm using to program my custom board). Is there something specific I need to do to see the downstream microcontroller (the one on my custom PCB)?

Secondly, while looking at other threads I came across this one describing a similar error but on a different chip. It turns out that when I comment out "idle_state_handle()" I can build & run!! Problem is ... well I don't know what the problem is normally. Why does idle_state_handle() break the code? I don't think it has anything to do with my custom PCB's power planes since I'm still just powering the custom board with the dev kit (which is connected to my computer with a usb cable).

We're getting close! I can almost taste it.

Kindest regards,

Ryan

[JONATHAN LL]

ryerye120 said:

Firstly, when I plug my boards into the nrf connect programmer, I can only see the dev kit (that I'm using to program my custom board). Is there something specific I need to do to see the downstream microcontroller (the one on my custom PCB)?

This is the expected behaviour, It is the debugger/programmer chip that is shown. 


I dont quite see what could be the issue with idle_state_handle(), is it only for the ble_app_blinky you have tested this? any other changes you do to the applicaton?

I think i will take a look at the HW and schematics first and then we can go from there. Can you provide them as PDF and if you have the HW files as GERBER that would be fantastic. 

Regards,
Jonathan

[ryerye120]

JONATHAN LL said:

This is the expected behaviour, It is the debugger/programmer chip that is shown.

I've only tested this with ble_app_blinky so far. I made 2 changes, 1 was commenting out idle_state_handle() and the other was to the pinout of LED4 (because that is different between the dev kit and my pcb). I will try another example! 

I am working on getting the gerbers - in the meantime here are pdfs of the schematic and layout. This board is meant to test a custom IC that our research group designed, the nrf52840 is in the top left of the board.

Thanks again for your help!!

board_schematic.pdfboard_layout.pdf

[JONATHAN LL]

So after looking at the schematic and layout pdf files, i have some comments, the layout you have does not exactly follow the recommendations we have for the nrf52840 and the deviations can\will effect at the very least RF performance. 

There is enough space on the PCB that is should not be an issue to copy\paste the ref design on to the PCB. If you want i can provide more details on the layout of the nRF. But to keep things short it will mostly contain references to the ref design, best to have GERBER files to properly review and address the potential changes. 

As for the cause of the issue you have now i dont think that it is HW related at the moment.

Regards,
Jonathan

[ryerye120]

Hi Jonathan,

Thank you for looking at the schematic and design! It's been a while since I did the schematic/layout but I think we were trying to stay as close as possible to the CKAA WLCSP schematic #3 with a few changes to the antenna (we wanted to use a dedicated antenna chip). Here are the appropriate gerbers (I think). I would really appreciate any feedback!

gerbers.zip

As for other examples I have tested ble_app_alert_notification and ble_app_beacon and both exhibited the same behavior as blinky. Worked the first time with build & debug. If I power cycled the board or did a "build & run" they board would halt. If I commented out "nrf_power_mgmt_run()" things work as expected.

As always, thank you for your help,

Ryan