From wpdster@gmail.com Fri Jul 08 02:41:02 2011 Received: from mail-fx0-f53.google.com ([209.85.161.53]) by stoneboat.aleph1.co.uk with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.72) (envelope-from ) id 1Qf03s-0001i3-7Y for balloon@balloonboard.org; Fri, 08 Jul 2011 02:41:02 +0100 Received: by fxd23 with SMTP id 23so1509098fxd.40 for ; Thu, 07 Jul 2011 18:40:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type:content-transfer-encoding; bh=/g+54gyG+cx0o6Y7vVz9/teu0w7lGQgKQmZHqMpIuoc=; b=lreuRSLZkiruT1+dTrPP2LeP9nKK8kCBLMLlLqb06iADIagq7RGC8wXVU55fp6q3mX 0ybxbxRpQcnd9FWaoateOHmqMgvuGNpUMAzat4Rpdl1s0wSjo8c5YYruD6f2vWUdePgd 6kliogmjBttlOxZmWulkyoSwyvsx/xM7iruvc= Received: by 10.223.16.131 with SMTP id o3mr2207600faa.53.1310089250285; Thu, 07 Jul 2011 18:40:50 -0700 (PDT) MIME-Version: 1.0 Received: by 10.223.123.20 with HTTP; Thu, 7 Jul 2011 18:40:30 -0700 (PDT) In-Reply-To: References: From: Patrick Doyle Date: Thu, 7 Jul 2011 21:40:30 -0400 Message-ID: To: balloon@balloonboard.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 209.85.161.53 X-SA-Exim-Mail-From: wpdster@gmail.com X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on stoneboat.aleph1.co.uk X-Spam-Level: X-Spam-Status: No, score=-3.2 required=4.5 tests=AWL,BAYES_00,FREEMAIL_FROM, RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.1 X-SA-Exim-Version: 4.2.1 (built Mon, 22 Mar 2010 06:51:10 +0000) X-SA-Exim-Scanned: Yes (on stoneboat.aleph1.co.uk) Subject: Re: [Balloon] Should SA_SDCLK0 be wiggling on my Balloon board? X-BeenThere: balloon@balloonboard.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Balloon List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 08 Jul 2011 01:41:02 -0000 On Wed, Jul 6, 2011 at 11:57 AM, Patrick Doyle wrote: > Before I go too far down this path, I figured I should just ask the quest= ion... > > The SDCLK<0> output pin on the PXA270 is wired to SA_SDCLK0, which is > wired to pin Y11 on the FPGA. =A0I would like to run some synchronous > logic (specifically, a dual clocked FIFO) off of this clock. =A0Right > now, it doesn't seem to be wiggling. =A0I can think of 2 reasons > immediately why I might not see it wiggling: > > 1) I did something wrong. > > 2) It doesn't wiggle unless it is configured to do so, and the default > kernel doesn't configure it to wiggle. > > I'm working on trying to figure out option (1). =A0I thought I should > ask you folks about option (2). > It seems like I need to set the K0FREE bit of the MDREFR register. I can do that fairly easily and hackilly by just OR-ing MDREFR_K0FREE into MDREFR inside a loadable kernel module. Is there a better (kernel or even user space) API for examining and manipulating bits in MDREFR and other registers? --wpd