Multiple Clocks to on board compoents

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originally posted by kaku817+feb 17 2005, 03:15 am--><div class='quotetop'>quote (kaku817 @ feb 17 2005, 03:15 am)</div>

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<!--quotebegin-camelot@Feb 5 2005, 06:25 AM

you should to change video_clk into pll to 25 mhz, but not clk of dac.

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It needs change both the vdeio_clk to 25.175Mhz and the PCB design of Lancelot board.

In the Lancelot board, you must cut-off 1-2 connection of J1, connect 2-3 of J1,

and add a 25.175Mhz OSC to X1.

Of couse the related registers of Lancelot board must be also changed to match 640*480

mode.

Now, because the clk for video DAC is from 25.175MHz OSC of Lancelot board, not from

buffered clk from PIN_E15, you can maintain the PIN_E15 to 50 MHz to SDRAM devices and

CPU.

Hope this is helpful.

--

Kaku [/b]

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Sorry, I am wrong... Camelot is right.

No additional H/W modification is needed!

It needs only change &#39;vga_clk&#39; to 25MHz and maintains PLD_CLKOUT (PIN_E15) in 50MHz.

Of couse the related registers of Lancelot board must be also changed to match 640*480

mode.

--

Kaku