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Re: Annoying Problem With SPI interface to Atmel Dataflash

2006-05-18 by brendanmurphy37

--- In lpc2000@yahoogroups.com, 42Bastian Schick <bastian42@...> wrote:
>
> brendan
>  >I think the basic problem is that the LPC213x SPI can only handle 
8-
>  >to 16-bit transfers, and the Atmel device requires longer ones.
> 
> I don't know of any SPI which makes longer frames than 16bit.
> If you need more you have to send more frames.
> 
> Only if the CS is really deasserted between frames you need to tweak
> the CS.

I guess it depends on what you call a "frame" or "transfer": I'd use 
the term to describe the transfer of a set of bits framed by some 
signal (in this case CS). I don't know the Atmel device specifically, 
but it sounds like it's transferring more than 16-bits at a time.

I'd agree it's best to try and use the SPI peripheral if you can: you 
clearly need to be careful though with polarity and timing of a GPIO 
CS. By the way, does anyone know if you can use SSEL as GPIO whilst 
using the other SPI pins as peripheral pins? if you can't you'd need 
an extra pin, which aparently is not an option in this case.

Brendan

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