custom serial wire debug

[Jon (jono)]

Hi, As question "custom serial wire debug" date Jan 14 '14, I'm also interested in programming the chip from an other embedded chip (would fit our production process verry well).

Do you have information about how to do this?

After looking at data sent on DW when using the dev-board "nRF51 DK" i notice that different code seems to be written to ram @ 0x20000000..0x200004BF.

Is this code avaliable?

May I use it myself in an own construction targeting your chip (or do you consider the code your property and I may not use it)?

(Or even simpler, can I program through AHB-AP directly without using a ram algorithm.)

[RK]

It's not Nordic's code doing the programming from the nRF51 DK, it's the on-board Segger chip which is programmed with Segger's JLink software, that's what's talking SWD to the nrf51 and is connected out of the board via USB. In all likelihood Nordic just uses JLinkDLL, which is Segger's wrapper library for the whole thing, which provides you simple high-level functions to write to registers, read and write files etc. I didn't know JLinkDLL wrote to RAM, but I guess it might, I'll have to look one day. Possible that Nordic's nrfstudio uploads a bootloader to RAM and then runs it, Crossworks does that (or did before Segger provided a generic flash loader), but I didn't think so, you don't really have to, JLinkDLL provides all this in 2 dozen c functions.

If you have an SWD emulator library for the big ARM CPU you may be able to make use of that, but you'll have to do the pretty low-level work yourself. Again depends a bit what libraries exist already for the CPU you're using.

Nordic has a bootloader/DFU module. You have to get it on the chip in the first place but you can then talk to that over UART if you like, with a very simple protocol. That doesn't help you get the initial image on however.

[Jon (jono)]

Hm, ok, If this is correct, it's seems not even to be Nordic:s code going down to target, and I canno't steel that... Seems that the remaining options then is to do it myself, one way or the other...