NRF52-DK P19 Programming Custom board question

[JC9191]

Hello,

I have a custom PCB which uses the NRF52832 chip and i wanted to program it using the NRF 52 DK using P19. I have the following connector and pin out on my custom board:

My custom board will be powered by lithium batteries into an LDO to give 3.3V. I have read that when using the DK to program that the target voltage must match the VDD voltage of the dev kit. If i solder SB10 to short out the reverse polarity diode to bring the board voltage to 3.3V would i be able to program my device using P19?

Any help with this is appreciated.

[Jared]

Hi,

The reverse voltage protection is there to prevent any damage when the nRF is supplied from more than one supply(which shouldn't happen). The connection in your schematic looks correct, but I'm wondering why you decided to use a pullup and pulldown on the SWDIO/SWDCLK line. Is this something you have tested before?

regards

Jared 

[JC9191]

Hi Jared,

Yeah i understand the protection diode. I've read that when programming a custom NRF52832 chip using the Nordic Dev Kit that the target voltage of the custom board should be the same as the VDD voltage of the dev kit chip which is 3.0 volts. If i remove the diode then VDD becomes 3.3V which should match the voltage used on my board.

With regards to the pull up resistors, this was taken from the BlueMod S50 Development kit which contains an NRF52832 chip. It will be the bluemod s50 that we will be using. Do you not need these pull ups and pull downs? Are there internal resistors on these lines?

Thanks

[Jared]

Hi,

The SWD lines already have internal pullups so no external is needed.

 

JC9191 said:

Yeah i understand the protection diode. I've read that when programming a custom NRF52832 chip using the Nordic Dev Kit that the target voltage of the custom board should be the same as the VDD voltage of the dev kit chip which is 3.0 volts. If i remove the diode then VDD becomes 3.3V which should match the voltage used on my board.

 aha, I understand. Yes, this seems perfectly reasonable. 

regards

Jared 

[JC9191]

Hi Jared,

OK So it will most likely work using P19 and the wiring above?

Would you advise that i remove the pull up resistors and just have the SWDIO and SWCLK pins connect straight to the dev kit pins?

Thanks

[Jared]

Hi,

 We recommend following the reference design, which means that I would advise you to remove them,

best regards

Jared

[JC9191]

OK i will do. Are there internal pull ups and pull downs then? Do you have a link to the reference design?

Thanks

[Jared]

Yes, there are internal pullup and pulldowns. You can find the reference design here and also the design for the development kit here.