From owner-freebsd-arm@FreeBSD.ORG Mon Jan 28 13:36:02 2013 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 5DB546A4; Mon, 28 Jan 2013 13:36:02 +0000 (UTC) (envelope-from ray@ddteam.net) Received: from smtp.dlink.ua (smtp.dlink.ua [193.138.187.146]) by mx1.freebsd.org (Postfix) with ESMTP id 1E542AE2; Mon, 28 Jan 2013 13:36:01 +0000 (UTC) Received: from terran (unknown [192.168.99.1]) (Authenticated sender: ray) by smtp.dlink.ua (Postfix) with ESMTPSA id 1763BC493C; Mon, 28 Jan 2013 15:36:01 +0200 (EET) Date: Mon, 28 Jan 2013 15:37:47 +0200 From: Aleksandr Rybalko To: George Mitchell Subject: Re: Thanks for the Raspberry Pi! Message-Id: <20130128153747.cf3516ee1977538268584e48@ddteam.net> In-Reply-To: <51065DB9.4090406@m5p.com> References: <51065DB9.4090406@m5p.com> X-Mailer: Sylpheed 3.2.0 (GTK+ 2.24.6; amd64-portbld-freebsd9.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-arm@freebsd.org, freebsd-embedded@freebsd.org X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 Jan 2013 13:36:02 -0000 On Mon, 28 Jan 2013 06:15:05 -0500 George Mitchell wrote: > Today is my birthday, and the best present I have is that my Raspberry > Pi is running FreeBSD plus CUPS and acting as a print server for the > FreeBSD machines (and one Windoze machine) on my home network. My > sincere thanks go to everybody who helped bring FreeBSD to the ARM and > specifically to the Pi. It would be awesome if we could get ARM > promoted to Tier 1 support this year. > > I'm interested in working on a driver for the pulse-width modulation > audio output on the Pi, and I have the Broadcom document describing how > it works. What are the chances I could base such a driver on some > existing FreeBSD audio driver? -- George Mitchell > _______________________________________________ > freebsd-arm@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org" Hi George, Think you can base it on any simplest one. Main difference in the clock, so if you want 8bit resolution at 44100Hz, you will need to set pwm clock to 2^8 * 44100 = 11289600, and then just at freq 44100Hz program duty cycle for current sample. Problem only in clocks, because for 16bits you must set 2^16 * 44100 = 2890137600, so it is almost 3GHz :-D Good luck! WBW -- Aleksandr Rybalko