Date: Mon, 28 Jan 2013 15:37:47 +0200 From: Aleksandr Rybalko <ray@ddteam.net> To: George Mitchell <george@m5p.com> Cc: freebsd-arm@freebsd.org, freebsd-embedded@freebsd.org 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>
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On Mon, 28 Jan 2013 06:15:05 -0500 George Mitchell <george@m5p.com> 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 <ray@ddteam.net>
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