21-05-2025, 06:23 AM
No, I am referring to the first photo (with initial program) which shows the measured input, which is the true frequency divided by four because of the flip flops, and the resultant when multiplied by four by the Arduino. 2500047 x 4 = 10000188 whereas the Arduino shows 10000191. This is obviously a calculation error which I only noticed when I looked at the photos. As I said, probably not a problem in this application.
I have no easy way of checking the crystal oscillator. I imagine the indicated error is more the Arduino although it appears to have a crystal clock rather than the ceramic of earlier models. Just or reference, I bought two of these boards. Some time back when I was checking possibilities I compared the two boards with the same input (1 or 2 MHz crystal oscillator). There was about a 50Hz difference between them.
For the moment I have taken the offset from 10MHz (191 Hz in this case) and used it as an error adjusted for in calculation, although it's low enough not to show in 1kHz steps anyway.
As you will know, there is a lot of information needed to properly explain even a simple project like this which I didn't get into a short explanation. Much of it is in my mind, not on paper anyway, which is never ideal, particularly for follow on work at a later date. Perhaps a good use of a forum to promp things
I have no easy way of checking the crystal oscillator. I imagine the indicated error is more the Arduino although it appears to have a crystal clock rather than the ceramic of earlier models. Just or reference, I bought two of these boards. Some time back when I was checking possibilities I compared the two boards with the same input (1 or 2 MHz crystal oscillator). There was about a 50Hz difference between them.
For the moment I have taken the offset from 10MHz (191 Hz in this case) and used it as an error adjusted for in calculation, although it's low enough not to show in 1kHz steps anyway.
As you will know, there is a lot of information needed to properly explain even a simple project like this which I didn't get into a short explanation. Much of it is in my mind, not on paper anyway, which is never ideal, particularly for follow on work at a later date. Perhaps a good use of a forum to promp things
