Help needed : 11 ADC's in seperate module's on I2C ?

[The Assembly Programmer]

I need one ADC in each module and I have 11 module's. Every module is
connected through I2C. It's impossible to use in a module an analog
input from an ADC in another module. I know Philips has an ADC ( PCF
8591 ) that has 3 selectable address bits. With that, I can go to 8
ADC's but how do I connect more than 8 ADC's on I2C ?
Maybe an ADC with I2C exists from another manufacturer than Philips or
is there another solution ?

The Assembly Programmer.
asm...@mail.dma.be

[H. larsen]

The Assembly Programmer wrote:
>
> I need one ADC in each module and I have 11 module's. Every module is
> connected through I2C. It's impossible to use in a module an analog
> input from an ADC in another module. I know Philips has an ADC ( PCF
> 8591 ) that has 3 selectable address bits. With that, I can go to 8
> ADC's but how do I connect more than 8 ADC's on I2C ?

I suppose you have to segment your I2c bus in that case. For instance
you can put a controller in your card which you configure to have two
i2c ports (dont know if this is easy though)

> Maybe an ADC with I2C exists from another manufacturer than Philips or
> is there another solution ?

I have also been shopping for i2c ADC's and have found only the same one
as you!
>
> The Assembly Programmer.
> asm...@mail.dma.be
If you dont need the i2c for anything else on your card but the adc,
then I would definitely try to avoid I2c-adc's. There are a vast number
of adc's with 3 wire interface (clk, data, strobe).
So use a tiny controller (eg 80c752) as a bridge chip on your module
between your I2c bus, which goes between the 11 modules you have and the
3 wire interface.
I have no experience (yet) with I2c, but I recon, that you have to be
deadsure that your modules has a solid common ground connection, or
you will be having nasty noise problems later on. If you cant ensure
this, then I would forget I2C in this application!

Regards
Henning larsen
Risoe National laboratories
DK