Changing DE0-Nano P1 clock

escherescher Posts: 113
edited January 27 in Propeller 1 Vote Up0Vote Down
I want to use 104 MHz as my P1 base clock ( @Heater. and @Cluso99 and others have extolled its stability) as my VGA display routine needs those sweet sweet nanoseconds.

I see in the top file for the DE0-Nano P1 the following declaration:
pll	: altpll with (
		pll_type = "enhanced",
		operation_mode = "normal",
		inclk0_input_frequency = 20000,		-- 20000ps = 50	MHz
		clk0_multiply_by = 16,
		clk0_divide_by = 5);

This is allegedly supposed to result in providing a 5 MHz input clock signal to the P1... but I don't see how as (50 MHz * 16)/5 = 160 MHz. So I'm stuck on even starting to figure out how to change these or other parameters to provide the propeller with a 6.5 MHz input clock signal (which with the 16x PLL would give me 104 MHz).

Anyone have experience with this? Thank you!


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