Am 05.05.2010 09:39, schrieb J.Castane:
I'm working in a comunication between the Overo COM and external board
through SPI. The external board works at 5V, so here is a typical problem,
voltage levels traslation!

I've search in this forum for any solution and these are:

1) The logic level translator of Sparkfun
http://www.sparkfun.com/commerce/product_info.php?products_id=8745

  
Nope =)
This is a FET based solution, at least as i think, and i don't think it will support 1.8V operation.


2) The TXS010x (X-Bit Bidirectional Voltage-Level Translator for Open-Drain
Application) from TI
http://focus.ti.com/docs/prod/folders/print/txs0101.html

  

Nope =)
The TXS series of TI is for open drain operation, like for I2C aka TWI

3) This doc suggests the MAX8867/MAX8860 and the MAX1840/1841 (page 3)
http://pdfserv.maxim-ic.com/en/an/AN3007.pdf

  

The MAX8867 is just a voltage regualtor, but it might work with the MAX1840/41.


I need that the SPI works at 20Mbps so I think that the first solution it
won't work.

What's it in your opinnion the best choice? How can i do this voltage levels
traslation? Have anyone worked with SPI and OVero?

  

I used the 74AC164245 just like they did on the overo motherboards and run my spi and usart lines over it.
http://www.ti.com/litv/zip/scej158
Just be sure, that you set the direction correctly (8 bit in one direction, the other 8 in the other) and then it should work.


Regards

Bernhard W├Ârndl-Aichriedler