Date: Fri, 28 Mar 1997 11:12:07 -0700 From: Steve Passe <smp@csn.net> To: Richard Tobin <richard@cogsci.ed.ac.uk> Cc: multimedia@FreeBSD.ORG Subject: Re: newest bt848 driver Message-ID: <199703281812.LAA26563@Ilsa.StevesCafe.com> In-Reply-To: Your message of "Fri, 28 Mar 1997 17:44:15 GMT." <27726.199703281744@pitcairn.cogsci.ed.ac.uk>
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Hi, > Here it is with line numbers: > ... evidently I'd already fixed it in my local source. --- > Can anyone tell me what the XTSEL bits in the IFORM register select? > The driver sets them to XT0. this picks one of 2 crystals for use as the fundimental oscillator. NTSC uses 3.58mHz, while PAL I would use 4.43mHz. Note that the actual crystal on your board will probably be 8 times that value, so it would be 4.43 * 8 == 35.44mHz (approximately, 4.43 is probably rounded off). i think the input used is arbitray, ie the card maker could choose to put either crystal on either input. IF they follow the brooktree suggested order: IF there are TWO crystals on the board (dual NTSC/PAL support) NTSC will be on XT0 (01b << 3) and PAL I will be on XT1 (10b << 3) I IF there is ONE crystal on the board (NTSC or PAL) The one crystal will be on XT0 (01b << 3) The databook chart for PAL I says IFORM should be: 0xx1 0011 where xx is the MUX input field. it further states that HSCALE should be 0x033c, ADELAY should be 0x7f, and BDELAY should be 0x72 -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD
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