Added RP2040 Support

[Intubun]

And again added RP2040 Support for this Lib

[RobTillaart]

You did a lot of work! Thanks!

[RobTillaart]

build failed on

/home/runner/Arduino/libraries/MCP4725/examples/MCP4725_wave_generator_RP2040/MCP4725_wave_generator_RP2040.ino:49:7: error: 'class MCP4725' has no member named 'selectWire1'; did you mean '_useWire1'?
   MCP.selectWire1();
       ^~~~~~~~~~~
       _useWire1

If you refactor the begin() the example needs to be rewritten (partially) too.

[RobTillaart]

@Intubun

A good night sleep later I had some thoughts about the RP2040 support. As I do not have a RP2040 I cannot test this myself.

Is it possible to add the Wire or Wire1 instance in the constructor ?
That is already supported in the library, and if it works the PR is overkill.

MCP4725 mcp(addr, &Wire);

Can you give it a try?

The library does not track which Wire is used but is that a problem?

[Intubun]

Yeah, it actually works! But some changes are still required for the output config of the RP2040, since it has some variables for setting the output pins...

[Intubun]

And a useage example cant hurt ;-)

[smithjacobj]

I'd like to make mention that this requires Arduino-Pico and not the official Arduino Mbed board library (which doesn't have Wire::setSDA/SCL)

https://arduino-pico.readthedocs.io/en/latest/install.html#installing-via-arduino-boards-manager

[RobTillaart]

Thanks for this info. Will read the link later today if time permits.
Probably true for all I2C libraries?

[smithjacobj]

Not necessarily? I'm not an expert, but I assume that this is just for Arduino IDE Wire-compatible interfaces. I'm sure you can use other libraries to access it.

Part of this is my inexperience with using Arduino IDE with RP2040 (I've only used it with Uno before) but it might be nice to know "hey, you can't just select the default builtin RP2040, you need Arduino-Pico" in the README section.

[RobTillaart]

Thanks, I better reopen this issue as reminder to add the note in the readme.

Mm PRs cannot be reopened.

Created issue #23