alt.hn

6/2/2026 at 7:30:44 PM

JLink JTAG Access on the Pinecil

 https://danielmangum.com/posts/jlink-jtag-pinecil/

by hasheddan

6/5/2026 at 12:35:43 AM

I bought a Pinecil so I could run it off a battery. I really came to appreciate the excellent temperature control and rapid heating, and use it instead of my soldering station for jobs away from the bench.

I have felt absolutely no need to touch the firmware. I try to forget that it is more powerful than my first three personal computers combined. Plug in, turn on, get hot. It meets my needs and exceeded my expectations. I suppose I could run a website from it if I wanted to make a point but as long as it doesn't require wifi and phone home to verify the license and leak my biometric data I expect to use it until I wear it out.

by jakedata

6/5/2026 at 10:54:04 AM

I saw one useful feature added, which was support for lower resistance tips. You can also get it to report on the input voltage which is marginally useful if running on battery.

Most of it seems to be people having fun. Animations, enabling Bluetooth, web interfaces over aforementioned Bluetooth, etc. That's all pretty cool and hacker news is hardly the place to question why you'd want to do it, but I'll admit I find the number of people interested in hacking on a soldering iron a bit of a surprise!

by fancyfredbot

6/5/2026 at 4:13:00 PM

Do you run it at 20V or USB 5V? I ask because I found it heated up very slowly at 5V (and had trouble maintaining high heat), while once I got a nice USB PD power supply, it worked very well.

It replaced my weller almost instantly (the weller just inserts heat insert nuts now).

by dekhn

6/5/2026 at 4:57:58 PM

20v everywhere plus I made up a high power DC power cord with a barrel connector. My company’s marketing department has really nice USB-C power bricks emblazoned with our logo. I also invested in a biggish Anker battery with full USB-PD support.

by jakedata

6/4/2026 at 9:25:06 PM

Jlink is closed source.

Better use dirtyJTAG on an rp2040.

by zoobab

6/4/2026 at 9:41:55 PM

Agree RP2040 / RP2350 is great for debug and UART access! I wrote[0] about using picoprobe with this device as well.

[0] https://danielmangum.com/posts/risc-v-bytes-accessing-pineci...

by hasheddan

6/4/2026 at 10:25:14 PM

I tried to use picoprobe to debug an nrf52 chip, it failed to even detect it.. All that’s officially supported is using it to debug a raspberry pi, and maybe if I added 100Ohm resistors to the lines I would have had better luck, but.. alas

by 05

6/5/2026 at 2:42:26 AM

> I tried to use picoprobe to debug an nrf52 chip, it failed to even detect it

I've literally got a Pi Debug Probe and a nRF52840 dev board on my desk, so I gave it a shot - and it works just fine. Make sure the core is awake when you try to connect for debug, or connect under reset; SWD goes to sleep with the rest of the chip.

> All that’s officially supported is using it to debug a raspberry pi

The Pi Debug Probe is a generic DAPlink probe, and will work for pretty much any Cortex-M part. I routinely use mine for debugging STM32 parts.

by duskwuff

6/5/2026 at 9:08:13 AM

'Connect under reset' is an STM32 thing, nrf52840 can't really do that and the probe doesn't use hardware reset pin. Once the MCU is out of pin reset, Ctrl-AP can hold the mcu in soft reset, but that's the standard behavior.

The difference between Pico and Pi Debug Probe are those 100Ω resistors on CLK/DIO lines, so I guess it working for you means I need to try again with resistors soldered.

Thanks for verifying it works!

by 05

6/5/2026 at 11:09:56 AM

There's basically zero chance 100Ω resistors are contributing to your issues on a protocol that is host-clocked and can operate in the single kilobaud range.

Lower speed or try one of the other fifty debug firmware projects.

https://github.com/raspberrypi/debugprobe

https://github.com/bugadani/rusty-probe-embassy

https://github.com/probe-rs/rusty-probe

https://github.com/ciniml/rust-dap

https://github.com/ccattuto/rp2040-dap-probe

Not all firmware implements all modes or the CMSIS-DAP spec correctly (most don't implement JTAG, either.)

by 15155

6/5/2026 at 3:17:00 PM

Okay i'm officially a dumbass - looking at the pinout i can clearly see Arduino pins and normal GPIO pins are mixed up on the board I used (seeed xiao rp2040). Arduino strikes again!

Just checked - of course if works fine on proper pins

by 05

6/5/2026 at 6:27:00 AM

JLink + Segger Ozone is so, so good though. Supper fast to flash and really nice debugger.

by josephinies

6/5/2026 at 1:04:27 AM

Why that over the debug probe firmware?

by Graziano_M

6/5/2026 at 5:15:22 AM

It's been a long time since I messed around with this stuff, proprietary JTAG devices and debuggers used to be leaps and bounds ahead of open source ones. Is it still the same?

by zeafoamrun

6/4/2026 at 10:06:18 PM

Good to see an "organic" J-Link + RISC-V use case :)

by Sweepi