Raspberry PI Debug Probe - First Look

[@drfrancintosh]

I found this just in time. I wanted to gather debug output (telemetry) and was hoping to use the SWD pins. But this shows me that the "probe" may be a great way to both gather my debug output and SWD control. Many thanks! I'm subscribing.

[@DrJonEA]

Glad I could help. You could output messages from SWD on Pico. It's called semihosting but is currently marked as experimental in the SDK.

[@ianoliver7437]

Extremely interesting and an excellent presentation; certainly simplifies and makes the debug process a safer (at least in terms of connecting to more expensive devices)

[@DrJonEA]

Thank you.

[@gautombose4172]

Hi. Just wish your screen showing the cable connection between the (debug) JST of the Pico Debug Probe and the (swd) header pins of the pico board, was a bit neater. You may have noticed, that the manual of the Pico Debug Probe, does no indicate, (for the debug port), which pin is clock and which pin is Data. thankfully, the middle in is Ground (black cable). Hence not much damage will happen if the dupont connector was plugged in wrong way around.

[@DrJonEA]

Sorry about that. I plug them in the wrong way around all the time too. Though I have notes and diagrams from my course, I still use trial and error!

[@salus.populi6323]

Interesting - I may have a play with one of these. As a matter in interest, I’ve settled on using the Arduino IDE as my main programming environment for the Pico. While developing code, I always include a reboot() function which is called whenever I enter (say) ‘r’ into the serial monitor - this has the same effect as the Bootsel malarkey without unplugging.

[@DrJonEA]

Nice. tip. Thank you.

[@chrisjenkins1223]

I really like that idea. How do you implement it? (I don't know how to reboot the board from C code but this sounds really promising because I'm pretty bored of holding down bootsel at this point :-)

[@DrJonEA]

The only reliable way I know to reboot the Pico in C is using the watchdog timer. That does a clean reset. If you are tired using bootsel then why not use SWD?

[@chrisjenkins1223]

@@DrJonEA ERe using SWD, see my above reply. SWD works great on my Pico H but some of my devices don't have debug headers and I'm trying to come to terms with the fact that I'll need to learn to solder (and buy the required kit)!

[@DrJonEA]

Soldering isn't too difficult a skill, at least at through hole level. Even with my old eyes and shaking hands I can manage. Also things like clamps help a lot to hold things still.

[@sadOldMan13]

Could you please provide more detailed video about using this debug probe especially with old Pico board? I don't know why but there is none for now even though it is already a few months after Pico Debug Probe was launched. Thx in advance.

[@DrJonEA]

Thank you for the suggestion. I do have some tutorials showing much more detail on this within my Introduction to C Development Environment for Raspberry PICO course on Udemy www.udemy.com/course/introduction-to-c-development-environment-for-raspberry-pico/?referralCode=875319E04F95C9EC3414 There are a lot of options when compiling, flashing and debuging for the Pico. The course is able to do this in a set of tutorials. So shows how to flash from Windows, Ubuntu and Mac using the Debug Probe. Also to debug on those desktops from VSCode and Eclipse. What do you mean by old Pico boards?

[@sadOldMan13]

@@DrJonEA Just plain Pico having only SWD pins. I'm interested in Pico Debug Probe as it is not working for me. I'm not sure if I'm doing someting wrong but OpenOcd shows error: "unable to find a matching CMSIS-DAP device." Ports 6666 and 444 are open but no 3333.

[@DrJonEA]

Sounds like either SWD cable issue or openocd command line. I summarise the command line options you need for the different devices in an Instagram post which might help: instagram.com/p/Cqe7Nzttrnh/

[@sadOldMan13]

@@DrJonEA I replied twice here and none of my comment is here. What's up? BTW I've found problem.

[@DrJonEA]

None of you comments has been deleted. I can still see them, so sorry I don't know why you can't. As far as I can see nothing is up. Glad you found the problem.

[@bennguyen1313]

Is it possible it can debug other Arm chips via swd? Would that be just a matter of configuration (svd/cfg files).. or would it be more like picoprobe firmware changes and/or rebuilding openocd? For example, the Smartfusion2 fpga has a Cortex-M3 and the STM32H745 has Cortex-M7/M4 cores.. but both have an SWD interface for debugging. In addition, if the chip (M3+) also has ITM's SWO/TDO (for serial-wire-viewing) can pi-debug-probe + Eclipse/OpenOCD show this trace data? Or would that feature only be available in more expensive tools (Keil + J-Link-Edu/Mini)?

[@DrJonEA]

My understanding is that the RPI Debug Probe can be used with other SWD microcontrollers. I haven't tried that though. That would be just an openocd configuration to use.

[@chrisjenkins1223]

Many thanks for making this video. I've got a Debug Probe and it works great with my Pico H. One issue that I have is that some of my Pico-based devices, especially some of the cool pieces of kit that I've bought from Pimoroni, don't have SWD headers. As far as I understand it, I'd need to do some soldering to attach debug headers. Is that correct? The issue from my perspective is that I don't know how to solder well and don't have a soldering iron or the required paraphernalia. Assuming my understanding above is correct, could I persuade you to do another video showing how to attach SWD headers to a Pico or Pico W that doesn't already have them? That would be super useful for me and might motivate me to get into soldering.

[@DrJonEA]

Hi Chris, That is a great idea. Happy to show how to do that. Its something I do in my Pico Introduction course on Udemy (www.udemy.com/course/introduction-to-c-development-environment-for-raspberry-pico/?referralCode=875319E04F95C9EC3414), but I can share here too.

[@chrisjenkins1223]

@@DrJonEA Many thanks. I hope to do the above course some time soon, having really enjoyed your FreeRTOS on Pico course :-)

[@DrJonEA]

Thank you. If you completed the FreeRTOS course your probably beyond the intro course. I would recomend my IoT with Pico course though.

[@chrisjenkins1223]

@@DrJonEA coincidentally I bought that the other week! Just need to find time to sit down and do it.

[@andrewtschesnok5582]

I would probably get this just for the case it comes with. But once I learned that it "works differently" I'm not.. since it seems to add nothing new. (The Pico with the probe software offers both debug and UART also). It was a B*tch and half to get it working. At the time none of the instructions and online guides worked. But now that I got it working I would definitely not want to change anything.

[@DrJonEA]

Hi Andrew, once we get things working we tend to stick to our way of working. Certainly I do. There is a new version of PicoProbe out that now seems to be based on the same code set as the Debug Probe, so uses the same OpenOCD config..

[@andrewtschesnok5582]

@@DrJonEA Good to know. Thanks.