RE: Custom nRF52811 is not running off coin cell battery.

Kenneth — Wed, 02 Nov 2022 08:54:50 GMT

Remember to connect GND to GND_DETECT on the DK as well, see figure here:
https://devzone.nordicsemi.com/f/nordic-q-a/57070/doubts-about-programming/231822

Kenneth

RE: Custom nRF52811 is not running off coin cell battery.

Evan Knobler — Tue, 01 Nov 2022 21:30:03 GMT

Hello, thank you for the response.

I know the VCC line on the chip is properly connected because I read a constant ~3V when I probe it. I am connecting my external board via the configuration described in Programming External Board (BC832) with nRF52840 DK

I have also tried only connecting VTG, SWIO, SWCLK, and GND_DETECT between the DK and the external board, while powering the board with a battery, but still no luck.

RE: Custom nRF52811 is not running off coin cell battery.

patjshan — Tue, 20 Sep 2022 18:37:41 GMT

it sounds like the vcc of the chip is not properly connected to whatever is handling power on your board. The DK is likely supplying power to the chip when you have it connected over programming wires. I haven't used the 840 DK for programming but I use the 832DK frequently and I know that there is a chip select solder bridge that must be connected/disconnnected depending on if you would like to program an external board or the onboard chip on the DK. This may explain why you don't always see the LED light up even when you are connected to the DK.

I would suggest you probe the vcc pins on your custom board while a power supply is connected but without the DK connected. if you don't see enough voltage (I believe you need at least 1.7V to run but I'm not a nordic engineer so check that) the chip will not run. And if there is an issue with your board that you get worked out i would also suggest disconnecting the Vcc supply on the DK from the programming pads and only connecting Vcc target (the reference to the custom boards Vcc, this DOES NOT power the board butrather detects the voltage of the board the programmer is going to talk to) SWIO, SWCLK, and GND Detect (same idea as Vcc target, this is not actually the path for return current but the reference for the programming chip. Doing this has sped up the programming process for me immensely since you can plug in external power to your custom board and program it at the same time, allowing for useful ADC measurements etc. even while in debug mode.

Again I'm not a nordic engineer though, just been working with the chip for a while and that would be my first guess.