From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9745 invoked by alias); 24 Oct 2014 08:36:42 -0000 Mailing-List: contact ecos-discuss-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@ecos.sourceware.org Received: (qmail 9734 invoked by uid 89); 24 Oct 2014 08:36:42 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-la0-f54.google.com Received: from mail-la0-f54.google.com (HELO mail-la0-f54.google.com) (209.85.215.54) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Fri, 24 Oct 2014 08:36:41 +0000 Received: by mail-la0-f54.google.com with SMTP id gm9so2240968lab.13 for ; Fri, 24 Oct 2014 01:36:37 -0700 (PDT) X-Received: by 10.112.14.69 with SMTP id n5mr2922745lbc.34.1414139797522; Fri, 24 Oct 2014 01:36:37 -0700 (PDT) Received: from sg-pc.belvok.com ([86.57.137.251]) by mx.google.com with ESMTPSA id f4sm1627679lag.29.2014.10.24.01.36.35 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Fri, 24 Oct 2014 01:36:36 -0700 (PDT) Date: Fri, 24 Oct 2014 08:36:00 -0000 From: Sergei Gavrikov To: Oleg Uzenkov cc: eCos Discussion In-Reply-To: <544A0349.9020702@unicore.co.ua> Message-ID: References: <544618E5.90101@unicore.co.ua> <54479031.9080106@unicore.co.ua> <5447C1D0.3070906@unicore.co.ua> <544918B9.7000601@unicore.co.ua> <544A0349.9020702@unicore.co.ua> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-IsSubscribed: yes Subject: Re: [ECOS] small custom bootloader to start an app stored in flash X-SW-Source: 2014-10/txt/msg00045.txt.bz2 On Fri, 24 Oct 2014, Oleg Uzenkov wrote: > Redboot is a great piece of software. It is just I found that when you > enable some important features like FIS support, Redboot reserves > extra space in RAM memory. > The size of this reserved extra space in RAM equals to the size of the > largest section size in Flash. In case of stm32f407 it is 128KB. > Internal RAM is 128KB. As John Dallaway pointed out there is very > little sense in using Redboot without enough of external RAM on > stm32f4 devices. For example for Kinetis it is a different story, the > flash sections are uniform and quite small. > > For small systems external RAM chip significantly adds up to the cost > of a device. I understand John's point and agree with him. But, he told about using debug infrastructure of RedBoot (debugging eCos applications in RAM). But, RedBoot is *debug* and *bootstrap* environment for eCos. I pointed on another side of RedBoot, *bootstrap*. You can quite run eCos [ROM] builds from FIS. Those [ROM] applications may utilize all RAM (128K + 64K) on your target. On start ROM application just does overlay RedBoot memory. You saw that yesterday with Rainer's approach (exec). If you cannot manage run [ROM] applications with RedBoot command 'go', just implement one new command for RedBoot, e.g. 'xip' (as RedBoot already uses 'exec' name to run Linux kernel). RedBoot will let you to use FLASH I/O, load any images, use start scripts, etc., etc. Of course it is my opinion only. Sergei -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss