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!