OnBoard Programmer

[roboflank]

Can we have an onboard programmer, probably a JTAG?
I've made a fork and am working on the changes.

Regards.

[urish]

Hi @denzelwamburu! It is currently possible to program using either over the air DFU (see here for instructions) or using the 4-pin header connector that exposes the ARM serial programming interface. The pin out is similar to the one found in this J-Link programmer which I am using the program my board.

That said, I am considering replacing it with a more standard Cortex M debug connector in the future. What are you currently working on?

[roboflank]

My idea was to integrate the debugger on board as well as a coin cell charger to harness power from the usb connection. This would be helpful in field applications. My main aim was adding the charger but also felt i could play around with the idea of the debugger.

[urish]

Sounds cool!

I had an idea of replacing the coin cell with a super capacitor + adding USB charging. I built a small prototype. Charging was super quick (just a few seconds), but it could only last an hour or so on a single charge, which was too limited in my opinion.

Are CR2032 lithium cells rechargeable? Or would you need to replace it with a lithium-ion cell?

[roboflank]

We need to replace,here are some models that are rechargeable
https://www.sparkfun.com/products/11928
http://www.ebay.co.uk/itm/2-x-3-6V-LiR2032-Rechargeable-Coin-Button-Cell-Battery-Li-ion-replace-CR2032-UK-/400871754904

An example circuit: https://oshpark.com/shared_projects/Q9b7sRrL

[urish]

Awesome!

Seems like the rechargeable ones are 3V6, which means we also need to drop down the voltage. If I recall well, 3.6 is the top limit of nRF52, and these batteries probably deliver more than that when fully charged

[roboflank]

Yeah, an extra resistor ? 😬