From owner-freebsd-doc@FreeBSD.ORG Thu Jan 6 06:06:45 2005 Return-Path: Delivered-To: freebsd-doc@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BCAF816A4CE for ; Thu, 6 Jan 2005 06:06:45 +0000 (GMT) Received: from mail16c2.megamailservers.com (mail16c2.megamailservers.com [216.251.41.136]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4250A43D31 for ; Thu, 6 Jan 2005 06:06:45 +0000 (GMT) (envelope-from phil@ridgetop-group.com) X-Authenticated-User: phil.ridgetop-group.com Received: from [127.0.0.1] (216-39-183-37.ip.theriver.com [216.39.183.37] (may be forged)) (authenticated bits=0) by mail16c2 (8.13.1/8.13.1) with ESMTP id j050CKnR027886 for ; Tue, 4 Jan 2005 19:12:22 -0500 Message-ID: <41DB30E3.4090101@ridgetop-group.com> Date: Tue, 04 Jan 2005 17:12:19 -0700 From: Phil Spuhler User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.3) Gecko/20040910 X-Accept-Language: en-us, en MIME-Version: 1.0 To: doc@FreeBSD.org Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Subject: UART frequency drift X-BeenThere: freebsd-doc@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Documentation project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 Jan 2005 06:06:45 -0000 Hi, I have a question regarding your documentation on the UART. It says that the frequency drift on the asynchronous clocks can be up to 10% total. Shouldn't this be 5%? My reasoning on this is that if the bits are sampled in the center, the total frequency offset can be high enough to shift the sampling to the edge of the bit in 10 samples --> 50% shift / 10 samples = 5%. Cheers, -Phil