max speed of SPI is 30 or 55 Mb/s?

i read in the spi tutorial from at91.com that the max speed of spi is
55Mb/s but in the datasheet write that the max clock speed on IO pin in
30 mhz.so i want to what is the max speed of SPI in master mode? Start a New Thread

Theorethical speed = MCLK (UMHz max. guaranteed)

Practical speed(=physical/electrical) however,
is 30MHz because of I/O-slewrate etc.

Conclusion, it's only usable upto 30MHz.
(for typical loads & board-trace lengths ...)

BR
-Morten

> -----Original Message-----
> From: A...
> [mailto:A...] On Behalf Of naderus2000
> Sent: Friday, July 14, 2006 5:19 PM
> To: A...
> Subject: [AT91SAM] max speed of SPI is 30 or 55 Mb/s?
>
> i read in the spi tutorial from at91.com that the max speed
> of spi is 55Mb/s but in the datasheet write that the max
> clock speed on IO pin in 30 mhz.so i want to what is the max
> speed of SPI in master mode?
>
>
> Start a New Thread

--- In A..., "naderus2000"
wrote:
>
> i read in the spi tutorial from at91.com that the max speed of spi
is
> 55Mb/s but in the datasheet write that the max clock speed on IO
pin in
> 30 mhz.so i want to what is the max speed of SPI in master mode?
>

I have asked support team at Atmel - same question, when I tried to
clock an external Atmel DataFlash Memeory(45DB161D) at around 50MHz
clock and getting wrong result above 30MHz clock spped. Their answer
was - You can use SPI at 30MHz clock only - because max IO clock is
30MHz.

I can not get reply - how to achieve 55MHz max SPI speed practically.

May be a marketing Hype!

Regards
Vinay Start a New Thread