Issues flashing firmware to custom PCB

[Ekse]

Hello!

We are a student group from NTNU which is developing an BLE Audio Beacon using the nRF54L15 socket and the nPM1300 PMIC. However, we have ran into some issues when trying to flash the board using the debug out connector from the nRF54L15 DK. We have soldered multiple boards and get the same error message on all of them:

This happens on all the boards, flashing from different computers and with different devkits. The SWD_SELECT pin is connected to GND on the custom board:

The nPM1300 supplies the nRF54L15 with 3V, and is confirmed with measurements on the VDD_nRF pin on the debug connector. The SWDIO and RESET pins are measured high by default, while the SWDCLK is low. 

By measuring SWDIO and SWDCLK on the oscilloscope we can see the debugger trying to flash the board by dragging the data pins low. 

Below are pictures from the schematic and the debug connection to the custom PCB. 

We are currently using SDK version v3.2.4, Mac OS, Linux and Windows and this is hardware revision 1.

Any help would be appreciated :)

Sincerly,

Mathias Ekse, Andreas Tranvåg and Mikael Gaudet.

[Kazi Afroza Sultana]

Hello Mathias, Andreas and Mikal,

It seems like debugger port is unavailable. Is the nRf54L15DK and your customer board are powered by same voltage level? You can set the VDD on board configurator app on the nRF Connect for Desktop app. 

You can read this also Debug out for programming external boards to check if the connection is ok.

Thanks.

BR

Kazi

[Ekse]

Hi Kazi,

Yes, we have set the level to 3000 mV, which is the same measured on the nRF, and it doesn't change the outcome while flashing. The connections checks out with the debug out connector from the link you sent. Do you have any other suggestions?

Best regards,

Mathias, Mikael and Andreas

[JONATHAN LL]

Hello there Mathias, Mikael and Andreas!

Often the issue lies with the onboard debugger chip not understanding that the external device is power in some way. 

You only need nRF_VDD, GND, SWDI and SWDCLK to be able to program the external device. 

Try to power the custom board from the DK it self, I find it easier to source the power and GND from the DK it self with some jumper wires just to make sure the logic levels are all the same. 

Have you tested the cable you are using on another setup to confirm that it works? 

Also see that its been a few days, maybe you have solved it already?

Regards,
Jonathan

[Ekse]

Hi Jonathan,

Yes! We actually managed to solve it. The issue was that the qfn48-package wasn’t properly soldered on. We had some suspicion when we realized the DECA rail had no power. We were not sure if it was a configuration issue or if it was supposed to come up by default, but we figured we would try to reflow the chip.

Eventually, after a few tries we saw that DECA got voltage, and after that we were able to flash the device.

Thanks for all the suggestions!

Best Regards,

Mikael, Andreas and Mathias