Blink example, clk frequency and blinking rate

[Aclassifier]

In IceCore Getting Started there is some example code that one can clone from git.

One of these examples is the blink.v. The function blink there is "called" from function chip in file chip.v. In the latter clk is said to be 25 MHz. I am not certain which config file that defines this. In chip.blif I find clk used in the [24] large reg in blink.v. But where is 25 MHz defined?

The reason I ask is that the blinking blinks at a period of 1.34 s. However 25.000.000 / (2exp24) = 25000000 / 16777216 = 1.49.. - if this is the correct calculation. If I increase the reg size to 26 I get two more bits and 2exp2 = 4 times longer period, seen as 1.34 * 4 = 5.4 seconds period. I am scoping it. You can see the diff from the builds shown here.

Either my reasoning is wrong (most probably) or it's not 25 MHz? 22.5 MHz suits better from my calculations since 22500000 / 16777216 = 1,3411045074462891.

[lawrie]

2 ** 25 / 25000000 = 1.34217728

[Aclassifier]

Of course The period is one more bit. It always is.. Arghh. I should have seen it, @lawrie. But those things are the most difficult. It's almost relevant what a lecturer at the university postulated years ago, after a long line of mathematical reasoning: "the sign has to be tested for". However, according to that axiom the period could even have been one bit less..