From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19658 invoked by alias); 3 Jul 2005 19:42:18 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Received: (qmail 19644 invoked by uid 22791); 3 Jul 2005 19:42:14 -0000 Received: from londo.lunn.ch (HELO londo.lunn.ch) (80.238.139.98) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Sun, 03 Jul 2005 19:42:14 +0000 Received: from lunn by londo.lunn.ch with local (Exim 3.36 #1 (Debian)) id 1DpALZ-0001ie-00; Sun, 03 Jul 2005 21:41:45 +0200 Date: Sun, 03 Jul 2005 19:42:00 -0000 To: Steven_cheng <05071@alphanetworks.com> Cc: Andrew Lunn , ecos-discuss@sources.redhat.com Message-ID: <20050703194145.GL8479@lunn.ch> Mail-Followup-To: Steven_cheng <05071@alphanetworks.com>, Andrew Lunn , ecos-discuss@sources.redhat.com References: <01df01c57e22$1291cca0$016ffea9@stevencheng> <20050701124913.GK5563@lunn.ch> <000101c57ff2$07c6cf10$016ffea9@stevencheng> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000101c57ff2$07c6cf10$016ffea9@stevencheng> User-Agent: Mutt/1.5.9i From: Andrew Lunn Subject: Re: [ECOS] What is the different between "ROM" and "ROMRAM" in the Bootup type ?? X-SW-Source: 2005-07/txt/msg00031.txt.bz2 On Sun, Jul 03, 2005 at 09:41:27AM +0800, Steven_cheng wrote: > Dear Andrew, > > Thank you for you reply, but I still confuse about the following > questions. > > 1) When the board powers on, does the CPU need to know which type and > vendor of ROM flash?? (ex. AMD 29LV040B) No. It should be able to read from any type/vendor. You only need to know more when you come to erase/write. But its not the CPU that does what, its you application program. > 2) How does the CPU know the memory address which the ROM locates ?? It is hardwired. Read the data sheet for your processor and look at the schematics to see what chip select it is using. Andrew -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss