Let's Make Robots!

connecting an i2c device with an AXE020 project board.

I've been thinking about playing around with i2c devices and I want to find a way to connect them to my

Axe020 project board. This thing.

After some initial problems with finding the pins on the project board that correspond to scl and sda

on my Picaxe 28X1, I finally found out that they are connected to the digital in 3 and 4.

Then I saw that all digital input pins have 10k pull down resistors on the project board, 

and I know that you need them connected to 4k7 pull up resistors to make them work with i2C devices.

This might be a really silly question, but will this be a problem, and if so, is there a way past it?

 

Lately I've been considering getting one of these to avoid future problems like this one.

Maybe I should get one before continuing with i2c?

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I read about that, waiting for serial input, thing. You're right, it wouldn't work for this.

I guess I'll try doing it with a single 28X. I'm leaning toward getting the module for breadboarding and use that for this project and keep my 28X with the project board free for other projects that don't demand I2C.

 thanks for the advice.

 

Hmmm. Yup, I guess this is another axe20 pitfall. I do like the idea of that SMT x2 with all the sync stuff on it's back. This would be ideal if you are breadboarding. Not to mention it, in any PCB or breadboard situation, you would never have to reproduce any sync stuff. --Much faster.

Another option --its a pain in the ass, but...

You can use your axe20 board to program the chip then transfer the chip to the breadboard for testing.

I'd probably be killing quite a few chips doing that.

It would have been nice if they had left some way to connect stuff before the pull-down resistor so you could still use the scl and sda if you chose to. but I guess you can't get everything.

I think I'll be getting the module then. I was going to buy the AXE031 servo controler anyway so I'll just throw the 28X2 module in with that order. 

Thanks for the input. 

I have used Devantech I2C Compass module with 28 pin project board. I had some problems with communicating over I2C, but it turned out power supply and faulty chip problems. Compass works well now. So, I believe you should give your project a shot with 28 pin board.