The datasheet says 20MHz is okay to go into HSPLL. You just use a /5 prescaler and the resulting 4MHz is then used to produce a fixed 96MHz PLL reference clock.
What I can't configure however is the 4x slower operation (I want 'pause 1' to actually pause for 4ms!).
I just wanted to see if i could pull this timing thing off without having to use a different xtal. I started everything with 20MHz HS but now that I'm forced to use HSPLL, which is new to me, I know 20 won't work so I'm done with it. The reason I'm moving to HSPLL is because my circuit only enumerates consistently on PC's but not Mac's, unless I use HSPLL instead of HS.
I'm sure both 12 and 24 will work but is there any preference?...unless there is some other way to get the timing I want and still use the 20MHz xtal!
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