Wich PIC? 8 analog in, I2C out.

[Odin]

I'm working on a project for a friend. He wants to read 8 analog values, and send them by I2C to some other circuits. Some pots, me thinks.

I've tried to find out what pic to choose, but get a little bit confused over the terms slave and master. Seems like the small pics can only be a slave? Or are there functions in there I don't understand.

What I have at hand here now is 16F73, 16F870 and 16F628. As far as I've understood, the F73 has some I2C functionality, although only 5 A/D-channels. But I could test with 1 channel first.

Please guide me in the right direction..

Thanks!

 

[Nigel Goodwin]

I'm working on a project for a friend. He wants to read 8 analog values, and send them by I2C to some other circuits. Some pots, me thinks.

I've tried to find out what pic to choose, but get a little bit confused over the terms slave and master. Seems like the small pics can only be a slave? Or are there functions in there I don't understand.

What I have at hand here now is 16F73, 16F870 and 16F628. As far as I've understood, the F73 has some I2C functionality, although only 5 A/D-channels. But I could test with 1 channel first.

The PIC16F877 is a very common PIC, it's 40 pin and includes 8 A2D inputs plus I2C capabilities.

A lot depends really what he wants to do with the values, I2C is a protocol for connections between particular compatible IC's, it's not a very good general purpose interface - you can do it far easier, faster and better.

I2C can be either Master or Slave, usually the micro-controller will be Master, storing analogue readings in I2C EEPROM is a very common task.

If you consult my tutorials I show how to read analogue inputs, and how to read and write I2C - but using software Master routines, not the 16F877 hardware.

 

[Odin]

The PIC16F877 is a very common PIC, it's 40 pin and includes 8 A2D inputs plus I2C capabilities.

A lot depends really what he wants to do with the values, I2C is a protocol for connections between particular compatible IC's, it's not a very good general purpose interface - you can do it far easier, faster and better.

I'm not sure, but I think these pots (potmeter IC) are for I2C only. So I have to stick with that.

I2C can be either Master or Slave, usually the micro-controller will be Master, storing analogue readings in I2C EEPROM is a very common task.

If you consult my tutorials I show how to read analogue inputs, and how to read and write I2C - but using software Master routines, not the 16F877 hardware.

So I should go the software way, and not bother with hardware I2C? Thought it would be a lot easier to use the hardware. Guess I could use any PIC with 8 A/D-channels then. What about 16F676? It's small, cheap, internal osc. 8 ch 10bit AD.

 

[Nigel Goodwin]

I'm not sure, but I think these pots (potmeter IC) are for I2C only. So I have to stick with that.

That's fine, I2C isn't a problem, as long as you have a need for it.

So I should go the software way, and not bother with hardware I2C? Thought it would be a lot easier to use the hardware. Guess I could use any PIC with 8 A/D-channels then. What about 16F676? It's small, cheap, internal osc. 8 ch 10bit AD.

That would be fine!, as it's a master situation a software solution works perfectly, my tutorials contain both I2C code and code for using the A2D.

 

[Odin]

That would be fine!, as it's a master situation a software solution works perfectly, my tutorials contain both I2C code and code for using the A2D.

I'm using your code right now. Need some studying before I understand all of it, but it comes. Great help, thanx!

Had a look at Farnell. Seems like pics are getting cheaper with more functions everyday. Like computers. Good for us..