From owner-freebsd-multimedia@FreeBSD.ORG Mon Oct 16 17:25:12 2006 Return-Path: X-Original-To: freebsd-multimedia@freebsd.org Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 04C6D16A40F for ; Mon, 16 Oct 2006 17:25:11 +0000 (UTC) (envelope-from rick@kiwi-computer.com) Received: from kiwi-computer.com (megan.kiwi-computer.com [63.224.10.3]) by mx1.FreeBSD.org (Postfix) with SMTP id B3AE943D88 for ; Mon, 16 Oct 2006 17:25:04 +0000 (GMT) (envelope-from rick@kiwi-computer.com) Received: (qmail 77993 invoked by uid 2001); 16 Oct 2006 17:25:02 -0000 Date: Mon, 16 Oct 2006 12:25:02 -0500 From: "Rick C. Petty" To: Ian Smith Message-ID: <20061016172502.GB77730@keira.kiwi-computer.com> References: <20061016073124.GD23971@funkthat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Cc: freebsd-multimedia@freebsd.org Subject: Re: New port: pvrxxx for Hauppauge PVR150/500 X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: rick-freebsd@kiwi-computer.com List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Oct 2006 17:25:12 -0000 On Mon, Oct 16, 2006 at 05:52:21PM +1000, Ian Smith wrote: > > Even bit-banging, I expect that it should be able to service interrupts > between bytes - though not between bits, obviously - at least while Why obviously? There's a clock line, so I can't see why pausing even between the bits would hurt anything... so long as your transfer rate is below the 400 kbit/s throughput. I've done a lot of Atmel AVR i2c myself, even with direct bit-banging it seems to work just fine. Of course, if you could offload the bus timing you would see a huge performance gain, but that's not possible AFAIK in this case. > transmitting. I have very little experience with iic, but am currently > boning up on it for a board using two Atmel AVR processors connected by > iic via optocouplers. Even long delays between transmitted bytes should > be no problem unless the receiver has some unusual? timing requirements. Just the 400 kbit/s max. Try inserting delays between the bits. It should still work fine, as long as you transfer the appropriate number of bits. > I've had a few quick forays through iicbb and all in /sys/dev/iicbus but > admit to not making much sense of it compared to the simple AVR-asm code > I've been studying, especially regarding the various bus layers, but it > does appear that iicbb is pretty long in the tooth ('98?) The iicbb could use some cleaning up. I could take a look at it if no one else has the time/ability. -- Rick C. Petty