[U-Boot] at91 spi bus speed

wouter moors wmoors at gmail.com
Tue Feb 15 12:56:42 CET 2011


Hi,

I'm experiencing some strange spi behaviour with an at91sam9g20.
I changed the spi_xfer code (atmel_spi.c) to make use of the PDC that the
at91sam9g20 offers. This works fine, but only up to an spi bus speed of 10
to 12 MHz. After that I see the CS going down sometimes before the transfer
is complete. When the frequency is increased the issue starts appearing more
often.

I saw that in env_sf.c that the spi bus speed is set at 10 MHz and was
wondering if there was a specific reason for that?

10 MHz is acceptible but I would like to understand what is happening, so if
anybody experienced and maybe even investigated the problem, please let me
know.

Wouter Moors

-- 
there's only 10 kinds of people. The ones that understand binary and the
ones that don't.


More information about the U-Boot mailing list