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puuu / USIWire

USI based TWI/I2C library for Arduino
GNU Lesser General Public License v3.0
58 stars 18 forks source link

Bundling USIWire with MegaCore #17

Open MCUdude opened 2 years ago

MCUdude commented 2 years ago

Hi!

I'm currently working on adding Arduino support for ATmega165/325/645 and ATmega169/329/649 through an Arduino core called MegaCore. The catch is that they don't have a "standard" TWI interface, but USI instead.

I was wondering. Is it OK for you if I bundle a modified version of this library together with MegaCore? I'll of course give you the credit for your excellent work. The only modifications I'm planning to use is to change the class name from USIWire to TwoWire to make it compatible with other libraries that expect a TwoWire object. I'll also add a little preprocessor glue so that users can include Wire.h, and it automatically includes the USIWire library.

Thanks!

puuu commented 2 years ago

Hi, nice to hear that USIWire is of interest.

Feel free to use USIWire as you like. In fact, ATTinyCore bundled it. Unfortunately, changes do not come back to this repository. Please also check ATTinyCore for modifications.

Why TwoWire? isn't it just called Wire in Arduino?

IMHO, the cleanest way would be to use this repository as a git submodule. The glue would be a Wire.h (in a different directory) with include <USIWire.h>. USIWire.h introduce already Wire. If you need TwoWire add a additional line into your Wire.h.

MCUdude commented 2 years ago

Feel free to use USIWire as you like. In fact, ATTinyCore bundled it. Unfortunately, changes do not come back to this repository. Please also check ATTinyCore for modifications.

Thanks! I'll have a look at both libraries then.

Why TwoWire? isn't it just called Wire in Arduino?

The library itself and the object is called Wire. However, the class is called TwoWire. Here and here is examples of libraries that expect a TwoWire object to be passed to their constructors as arguments. These libraries wouldn't accept USIWire as their i2c driver.

I'm using submodules for the bootloader and Arduino core files, but I would prefer to have a copy of the library that I'm free to modify the code as I like. One example is changing the class name (USIWire -> TwoWire). Another example is to get this library to compile for the targets I'm using. At the moment this library does not compile for __AVR_ATmega325P__ and __AVR_ATmega645P__, so that's something I'll have to add to usi_io.h. The code examples bundled with this library appear to be written with ATtinys in mind, so the examples would also have to modified.

puuu commented 2 years ago

The library itself and the object is called Wire. However, the class is called TwoWire. Here and here is examples of libraries that expect a TwoWire object to be passed to their constructors as arguments. These libraries wouldn't accept USIWire as their i2c driver.

I see, TwoWire is the class name. In this case typedef USIWire TwoWire; or more C++ style using TwoWire = USIWire; would do the trick in Wire.h.

At the moment this library does not compile for __AVR_ATmega325P__ and __AVR_ATmega645P__, so that's something I'll have to add to usi_io.h.

I would be happy about such tested pull requests.