First steps - in a state of confusion :P

[seamusdemora]

I am running a Mac (13.7.1). I have installed both versions of the Arduino IDE: Version 2.3.3 and 1.8.19. I have tried to follow the online documentation here. I have managed to upload the 'Blink' example to my Pico-2040, and it actually works!

Giddy with success, I tried an example posted by @maxgerhardt. This is not working - here's the output from the IDE "console":

In file included from /Users/jmoore/Documents/Arduino/sketch_pico_copy_20241112190723/sketch_pico_copy_20241112190723.ino:8:0:
/Users/jmoore/Library/Arduino15/packages/arduino/hardware/mbed_rp2040/4.2.1/cores/arduino/mbed/targets/TARGET_RASPBERRYPI/TARGET_RP2040/pico-sdk/common/pico_stdlib/include/pico/stdlib.h:11:10: fatal error: pico/stdio.h: No such file or directory
 #include "pico/stdio.h"
          ^~~~~~~~~~~~~~
compilation terminated.
exit status 1

Compilation error: exit status 1

And so it seems I have failed to download something - but I don't know what. I installed via the Arduino Boards Manager, i.e. copied the URL & pasted it into the dialog.

What have I missed?

[earlephilhower]

..../4.2.1/cores/arduino/mbed/targets/TARGET_RA....

Err, looks like you're running the MBED core, not this one. Check the Tools->Board->Raspberry Pi RP2040/RP2350 has been selected. There's no 4.2.1 release of this core yet. :)

[seamusdemora]

@earlephilhower :

As it turns out I had both installed. I removed the MBED core, and now have only yours (ref screenshot below).

However, please note two things:

1. the error message complaining about no MBED
2. the Pico not connected message.

I've pressed & held the BOOTSEL button then I plug the 2040 into my Mac (several times). I can see the icon in the URHC of my Mac seemingly indicating that the 2040 is plugged in - HOWEVER, it says RPI-RP2 ... suggesting a 2350 is somehow mounted??

No idea what's causing the 1st error re "no MBED"

[Andy2No]

@seamusdemora You have to choose the correct core, using the Board menu, like this:

Tools->Board->Raspberry Pi RP2040(4.2.0)->Raspberry Pi Pico

Everything in Raspberry Pi RP2040(4.2.0) is a board definition for this core.

[seamusdemora]

Here's what I see in Arduino 2.3.3:

My interface looks different from yours... but have I not selected "Raspberry Pi Pico"??
Note that I did make some forward progress by getting a modem connected - which was the cause of the "Pico not connected" message I mentioned above.

Afterwards (with the RP2040 still plugged in & running the blink example), I click the Upload button, and this is what I see:

I still don't see what I am doing/have done wrong... HOWEVER: using find on my Mac from / (i.e. find / -type f -iname "*stdio.h*") I don't see any file named stdio.h that would seem to qualify; also do not see: pico/sleep.h at all.

What did I miss that should have installed this?

[seamusdemora]

Calling some extra attention to this:

using find on my Mac from / (i.e. find / -type f -iname "*stdio.h*") I don't see any file named stdio.h that would seem to qualify; also do not see: pico/sleep.h at all.

What did I miss that should have installed this?

[Andy2No]

Yes, that looks right. I'm using Arduino IDE 1.8.19, with a theme to reduce eye strain.

It looks like the example is based on pico_sleep from pico-extras, which is written for the Raspberry Pi SDK: https://github.com/raspberrypi/pico-extras

That probably means it would take some work to make it usable with this core and the Arduino IDE, unfortunately.

pico_sleep is here:
https://github.com/raspberrypi/pico-extras/tree/master/src/rp2_common/pico_sleep

You could try copying the files from there into your project folder, and changing the include path to just double quotes, and the file name, then see how far you get.

#include "sleep.h";

sleep.h is here:
https://github.com/raspberrypi/pico-extras/blob/master/src/rp2_common/pico_sleep/include/pico/sleep.h

Use the Download arrow to get a copy.

You also need sleep.c, which is here:
https://github.com/raspberrypi/pico-extras/blob/master/src/rp2_common/pico_sleep/sleep.c

• same thing, just download it and place it in your project folder.

[Andy2No]

Okay, it looks like this is more complicated than simply copying the code from there. There's an existing closed issue about it:

#345

The other approach is to learn how to use the SDK, which normally involves VSCode and CMake and/or Platform IO. Personally, I've never done that because I prefer to stick to the Arduino IDE. I do have a version of VSCode installed (called Codium) but I haven't used it much yet, other than for some Raspberry Pi bare metal examples. It doesn't strike me as something I'd want to use more than I had to.

[seamusdemora]

You've made me think of something I hadn't considered... I had assumed that all of the Pico examples from the RPi GitHub Examples repo would "just work" under this Arduino IDE. Apparently that's not the case - or seems to be if I read #345 correctly.

[Andy2No]

On Windows 7 (yes, I know), I'm getting matches for stdio.h in

C:\Users\andy\AppData\Local\Arduino15\packages\rp2040\hardware\rp2040\4.2.0\pico-sdk\src\host\pico_stdio\include\pico

and

C:\Users\andy\AppData\Local\Arduino15\packages\rp2040\hardware\rp2040\4.2.0\pico-sdk\src\rp2_common\pico_stdio\include\pico

[seamusdemora]

Yeah, but macOS would probably put those files in an entirely different place.

[Andy2No]

If you choose Preferences on the File menu (assuming it's in the same place on 2.x), you should see a link to preferences.txt, near the bottom. If you click that it should open the folder which is equivalent to my
C:\Users\andy\AppData\Local\Arduino15

which is the first part of those paths. From there, open packages, then rp2040 etc.

It's quite possible you don't need to specifically include stdio.h; I'm not sure. You could try commenting out that line (put // at the beginning). I'm in the habit of removing the # too, which was maybe needed once due to a pre-processor bug but probably isn't anymore.

[seamusdemora]

@Andy2No

If you choose Preferences on the File menu (assuming it's in the same place on 2.x), you should see a link to preferences.txt, near the bottom. If you click that it should open the folder which is equivalent to my
C:\Users\andy\AppData\Local\Arduino15

Here's what my Preferences looks like, but I don't see anything re preferences.txt.

[Andy2No]

Yes, the preferences path doesn't seem to be there. I suppose it's part of the Mac way of doing things. I expect the organisation of files inside that folder is the same as for Windows, once you find it.

I don't think it will all necessarily work but the examples from the SDK are all or mostly included with this core, AFAIK. I don't think the pico-extras part is though. In the Arduino IDE you should have some examples. In 1.8.19 they're under File->Examples, then scroll down to "Examples for.." followed by Arduino Pico, or the particular board you've chosen. You can also get to them on github from the Code tab for the repository, under libraries - there's an examples section for each library in there.

[seamusdemora]

"The Answer" was a bit convoluted in the end. It finally came together when I read this comment from @Andy2No ... thanks, Andy!

In addition to my mistaken assumption re using examples from the RPi GitHub repo, I had made a few other errors that have been pointed out in this (now) rather long Discussion.

Thanks to all for your indulgence. I'll now concentrate on getting @maxgerhardt 's example working. It compiles, but seems to get lost afterwards... but that's for another discussion :)

[maxgerhardt]

You can't copy-paste the pico_sleep example code because

1. don't overwrite the main() function. to write a proper Arduino sketch, you need loop() and setup()
2. you need the missing pico_sleep and hardware_rosc components copied into your project
3. the above mentioned components don't work in Arduino-Pico by default because they wanna reinitialize stdio uart stuff, which the Arduino core handles differently, so you have to comment that out

This is the PlatformIO project I used: https://github.com/maxgerhardt/pio-picosleep It should work the same in the Arduino IDE if you open the main.cpp as main.ino in it, and set the USB stack to "None". I uploaded using a Debugprobe on Pico (CMSIS-DAP) and measure the VBUS line with my Nordic PPK2's Ammeter, which was fed externally by the Debugprobe's VBUS.

[seamusdemora]

@maxgerhardt

This is the PlatformIO project...

So I gather that "PlatformIO" is some sort of "universal" development environment? Just thinking about that - and after watching the YouTube video that @Andy2No mentioned below - I have a question: "If 'PlatformIO' is as good as it seems, why do things like this Arduino-Pico environment even exist?" Surely there's tradeoffs??

[Andy2No]

As I understand it, the arduino-pico core can be used inside PlatformIO, and so can the Raspberry Pi SDK. I started using arduino-pico mostly because it works inside the Arduino IDE, which the SDK doesn't. The code it produces is more efficient too, IIRC.

I guess everything has its place. The Arduino IDE came first and it's a relatively simple and task specific thing that works well on older computers, and older versions of Windows. The PlatformIO IDE apparently needs at least Windows 10, because that's the requirement for VSCode. VSCodium (the variant of that I have) seems a bit sluggish, overly complicated and klunky, to me. AFAIK, it's compiled from largely the same source, so I expect the experience is similar with VSCode. VSCode is widely regarded as a serious tool for programmers though.

I think there's a strong argument for sticking with something you're used to, if it does what you need, because it takes time to learn something new. I can see the argument for PlatformIO though, so if you're not familiar with either, it's probably worth trying both.

I expect I'll try PlatformIO when I've switched to using Linux more. I have a couple of PCs that can dual boot Windows 10 or Linux (one Ubuntu Studio, one with Debian), but I still mostly use one with Windows 7. Windows 10 annoys me far more than it seems it should be able to. Linux seems more promising but I'm not strongly drawn to using it until I need to, which I don't feel I do, so far.

[seamusdemora]

Linux takes getting used to also. I've got several Linux systems - mostly Raspberry Pis that I've "collected" over the years. I've tried a few of the Linux distros with GUIs (Ubuntu mostly), but I found I did not like the GUIs because they seem to just "get in the way". Gnome for example (Ubuntu's default GUI), is god-awful IMHO. So - I like Linux, but I try to stick mostly to the small systems that I run without a GUI ("headless").

My "GUI computer" is a Mac. But they have issues as well; largely methinks due to corporate greed. Overall, I feel I spend too much time with these computers! And so, I am trying to minimize... thus my preference to stick with the Arduino-Pico "IDE" over PlatformIO. I feel Earle has done a very good job with this repo.

My interest in Pico, and uC in general is mostly for off-grid systems (i.e. battery & solar powered). I'm here today because (again, IMHO) "Raspberry, Inc" has completely failed to "get on board" with their support for low power applications.

[Andy2No]

@seamusdemora Here's a video showing how to set up PlatformIO:
https://www.youtube.com/watch?v=QMYhVqjBhKQ

The first step is installing Microsoft VSCode, or possibly Codium (aka VSCodium) would work instead.

Edit: It seems VSCodium is not an option, due to licensing constraints:
platformio/platformio-vscode-ide#1802

[seamusdemora]

Interesting video... the guy (Gary?) is a v. good YouTube presenter. But for now, I think I'll try to stick with Arduino-Pico... IF I can just get that Pico low-power app running!