Re: [Gumstix-users] schematics for i2c logic level conversion

[Dave H. <dhy...@gm...>]

On Thu, Jul 16, 2009 at 1:21 AM, David Vescovi<dvd...@gm...> wrote:
> I would not use the Sparkfun option. This is just a one way level shifter. The
> I2C bus requires a bi-directional data line with open collector outputs. While
> you could possibility get it to work you would need at least two of these
> modules. Much better to go with the Maxim part which is ment specifically for
> I2C bus level shifting.

Huh?

The SparkFun level converter contains two bi-directional converters.

<http://www.sparkfun.com/commerce/product_info.php?products_id=8745>

The way that they've arranged the MOSFETS is exactly how the
bidirectional level converters are supposed to work.

Compare with this:
<http://www.headfuzz.co.uk/?q=node/46>

It's also the same design as talked about in several of the i2c
specification documents.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/