SPI question

[rnielsen]

Greetings!

Whenever I use I2C I will use a device, normally an LTC1694, to sharpen up the signals of the bus lines. I'm wondering if anybody ever uses a similar device to have the same effect on the SPI lines (or even if it's necessary). I have a project that will have the master and slave approximately 30 feet apart and want to ensure the signals are as clean as possible. It won't be in a noisy environment either.

Thanks!

Ronald
Why don't mosquitos suck fat instead of blood?

[Ttelmah]

Seriously, even in a 'non noisy' environment, you will need some ESD protection on lines this long.....
The main part of the question depends totally on the speed you intend to use, and the capacitance of the lines. You will also run into transmission line effects with lines this long. Assuming you are using SPI, because you want reasonable speed (otherwise don't bother, use something like RS485 instead). As such, you would be 'best off', accepting this, and properly terminating the lines to minimise reflection problems.
Use a line driver IC, with protection built in. Use a wire of known impedance, and terminate at each end.

Best Wishes

[bkamen]

Ttelmah's right.

Another option is to go optical.

http://www.i-fiberoptics.com/Fiber_optic_led_photodetectors.php

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D