From chris@martin-jones.com Mon Dec 17 20:16:02 2007 Received: from cheyenne.vervehosting.com ([75.126.59.90]) by stoneboat.aleph1.co.uk with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.63) (envelope-from ) id 1J4MNR-0001Nv-DB for balloon@balloonboard.org; Mon, 17 Dec 2007 20:16:02 +0000 Received: from cpc2-cmbg1-0-0-cust264.cmbg.cable.ntl.com ([82.21.105.9]:2555 helo=[192.168.1.6]) by cheyenne.vervehosting.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.68) (envelope-from ) id 1J4MNH-0005r6-Oz for balloon@balloonboard.org; Mon, 17 Dec 2007 15:15:17 -0500 Message-ID: <4766D967.30604@martin-jones.com> Date: Mon, 17 Dec 2007 20:17:43 +0000 From: Chris Jones User-Agent: Thunderbird 2.0.0.9 (Windows/20071031) MIME-Version: 1.0 To: Balloon Board References: <20071217092020.GA11370@guralp.com> In-Reply-To: <20071217092020.GA11370@guralp.com> X-Enigmail-Version: 0.95.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cheyenne.vervehosting.com X-AntiAbuse: Original Domain - balloonboard.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - martin-jones.com X-SA-Exim-Connect-IP: 75.126.59.90 X-SA-Exim-Mail-From: chris@martin-jones.com X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on stoneboat.aleph1.co.uk X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.2.3 X-SA-Exim-Version: 4.2.1 (built Tue, 09 Jan 2007 17:23:22 +0000) X-SA-Exim-Scanned: Yes (on stoneboat.aleph1.co.uk) Subject: Re: [Balloon] Playing with 13MHz X-BeenThere: balloon@balloonboard.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: Balloon List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Dec 2007 20:16:02 -0000 Bob Dunlop wrote: > Since there's been a little bit of discussion about 13MHz operation > on the IRC channel here's a patch I've been playing with to switch > the system in and out of 13MHz operation when idle. > > It works for me (saves about 200mW on a Compulab board) but I have done > no analysis of RAM timings etc. A similar patch to add 13Mhz as a > cpufreq stepping left my system stuck at 13MHz and I havn't worked out > why yet. (code snipped) Thanks for that, Bob. I've tried using those routines to jump in and out of 13MHz mode in the embedded code I'm working on and it has proved to me that my CPU isn't actually running at 13MHz, which means that my code's just too slow. Doh! Chris -- Chris Jones - chris@martin-jones.com Martin-Jones Technology Ltd, makers of Solidlights 148 Catharine Street, Cambridge, CB1 3AR, UK Phone +44 (0) 1223 655611 Fax +44 (0) 870 112 3908 http://www.solidlights.co.uk/