09:37 <wkoszek> Hi folks. What's the best cable for OpenOCD? I'm looking at the repo for the most frequently changed files, and it's stlink and jlink.

09:52 <antto> "cable" ?

09:52 <antto> do you mean debugger device?

09:54 <wkoszek> Yes.

09:54 <wkoszek> JTAG dongle

09:54 <antto> that probably depends on the targets you wanna deal with and the $$$$

09:56 <antto> i deal with cortex-M mostly, kamami zl33prog is nice (needs a saner connector/adapter but i'm fine with that)

09:57 <wkoszek> My friends made a custom board and I need 2x10 PIN connector with a ribbon cable and OpenOCD support - one CPU is Layerscape ARM and another one is 4-core RISC-V

09:59 <zear> wkoszek, I think we have the same friends :)

09:59 <zear> I personally use this jtag probe: https://www.tme.eu/pl/details/arm-usb-ocd-h/programatory/olimex/

10:00 <zear> including on boards our "friends" made, but I haven't tried it on the ones you listed

10:00 <zear> (I can try it at work tomorrow)

10:00 <wkoszek> Probably :) It's a small world

10:01 <antto> https://www.tme.eu/bg/en/details/zl33prg/programmers/kamami/

10:01 <zear> it definitely works with SAMA5D27 one board and I don't see why it wouldn't with the other ones

10:01 <wkoszek> I need something eBayable :)

10:01 <antto> tme never has it in stock, i bought it directly from kamami.pl

10:02 <zear> I think the question is - what bandwidth do you need? The majority of cheaper probes are limited by USB 2.0's bandwidth, which is good enough for stepping through gdb

10:04 <wkoszek> I think speed doesn't matter that much. I just need to flash this board.

10:06 <zear> then anything will work, but keep in mind that, unless your flash maps directly into addressable memory in rw mode, you'll need some sort of flashing script/driver

10:08 <zear> the proprietary jtag probes usually come with dedicated flashing firmwares for various boards

10:09 <zear> where, under the hood, they will upload a small program into RAM, which in turn talks to the flash chip using QSPI/whatever

10:10 <PaulFertser> You can often use U-Boot for that.

10:10 <zear> I think wkoszek needs to flash U-Boot firmware :)

10:10 <PaulFertser> I mean upload U-Boot to RAM and let it flash itself.

10:11 <zear> he has an empty flash chip

10:11 <zear> ah, that could work

10:13 <zear> wkoszek, the probe I'm using is available on e-bay: https://www.ebay.com/itm/256208773657

10:15 <wkoszek> Ok, that looks promising.

10:16 <zear> like I said, I can try it with your boards tomorrow (should we drop some names at this point, or are we keeping that confidential? :P)

10:17 <zear> iirc our "friends" normally use Lauterbach probes to flash them

10:18 <wkoszek> It's official and we're talking about https://www.conclusive.pl :)

10:18 <wkoszek> Who are you? :)

10:20 <zear> Artur Rojek :)

10:20 <wkoszek> U lala

10:20 <zear> the guys at work have a fixation on those Lauterbach probes, because they paid so much for them, they have to use them

10:21 <zear> but I prefer to stick to free software

10:21 <wkoszek> We have who is who of Polish embedded systems engineering here

10:22 <wkoszek> I remember you from 15yrs ago when I visited Semihalf

10:23 <wkoszek> I have 2 boards, and I need to get some servicing on them, and I'm in the US and I don't want to spend much $ on this stuff, as I'll likely debug them sporadically once I get Ubuntu on both of them

10:26 <zear> in general openocd is the way to go

10:26 <wkoszek> Yeah

10:26 <zear> just keep in mind openocd uses those jtag probes as "dumb" JTAG/SWD pass-throughs

10:27 <zear> the expensive proprietary probes usually have an FPGA w/ a lot of RAM inside, so they talk to the board directly

10:27 <zear> and spit out results over USB/ethernet back to the debugger

10:27 <zear> openocd doesn't work like that

10:28 <zear> with openocd the entire processing is done on your computer's side and needs to fit in the probe's bandwidth

10:28 <zear> so if you want to perform real time profiling, etc., openocd will not be a good choice

10:29 <zear> <wkoszek> I remember you from 15yrs ago when I visited Semihalf

10:29 <zear> I did work for semihalf, but not 15 years ago

10:29 <zear> so perhaps you're misremembering me :)

10:31 <wkoszek> Maybe I'm overestimating the time. But I think we briefly met during my rare visits there. And then I remember you from FreeBSD patches.

10:32 <zear> that latter part checks out :)

10:32 <zear> (I wish that I eventually get back to doing that)

10:41 <wkoszek> I think adding FreeBSD support to Conclusive boards could make sense.

10:42 <zear> agreed, but that's not up to me

10:46 <wkoszek> All right folks, thanks for all the help. I ordered this: https://tinyurl.com/jtagdongle

10:47 <zear> I think that will work

12:50 <PaulFertser> I have to note J-Link was nice enough and provided OpenOCD with some protocol documentation and their pricing seems to be reasonably fair so for business I would probably suggest buying devices from them rather than shady clones.

12:51 <PaulFertser> Olimex OCD-H is cheaper than legit J-Link and I'd say it should be about the same from OpenOCD performance point of view.

12:52 <PaulFertser> wkoszek: there's also J-Link EDU for for non-commercial projects

16:05 <wkoszek> To best support folks friendly to the community, I'd say this: https://openocd.org/doc/html/Debug-Adapter-Hardware.html needs to be updated

16:06 <wkoszek> I started to click on some JTAG cable links, and it's all not working

16:06 <wkoszek> And if this $60 J-Link Edu cable works in 90% of cases, maybe it should become THE cable.

16:16 <bencoh> except for commercial projects (at least in theory), but yeah

16:16 <bencoh> (olimex ocd adapter works just fine as well indeed)