From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Menzebach Date: Tue, 06 Jun 2006 12:02:06 +0200 Subject: [U-Boot-Users] AT91 u-boot lowlevel init Dataflash In-Reply-To: <44853F10.3060600@koansoftware.com> References: <44845F26.90504@koansoftware.com> <4485386D.5060908@schweigstill.de> <44853F10.3060600@koansoftware.com> Message-ID: <4485529E.2050900@mw-itcon.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Marco Cavallini wrote: > > BTW I wonder if could be useful (and appreciated) if I should merge > RomBoot settings into u-boot allowing u-boot to be the one and only > loader for Dataflash too. > > Ciao Hi, this is *not* possible, if you want to use only dataflash. *No* code can be executed directly out of the dataflash, since the access is serial and therefore it is not directly adressable by the CPU. So the boot sequence (slightly simplified) is as follows: - The internal boot code in ROM within the CPU copies up to 12K of code from dataflash to internal SRAM (this is romboot) and starts it. - romboot initializes CPU frequencies and sets up SDRAM (normally the CPU runs after this at 180 MHZ on the DK board, unless you got a buggy version of precompiled romboot. - romboot now copies u-boot to SDRAM and starts it. It use the romboot version from teest.com, which Andreas mentioned and this sequence works fine with the recent u-boot releases. You will find more information about this in various documents related to the processor and the dk board on the atmel home page.. Best regards Peter -- Peter Menzebach Menzebach und Wolff IT-Consulting GbR Phone +49 751 355 387 1