For this program it might take a bit of work. The program is set up to have
pre-calculated register values for all frequency ranges within the
specified limits, so the amount of calculation required for a small change
within a band is minimized. So you would need to expand the tables of
values all the way up to your desired 440 MHz limit to continue with that
method.

There's no reason you couldn't do it, but you'd have to study the code
(and/or the AA0ZZ QEX article) a bit to understand how the tables are
constructed.

I have expanded this basic program to one that includes display, rotary
encoder, TX/RX offset and so on, but I haven't expanded the frequency
limits because the version of the Si570 that I'm using is only specified to
160 MHz.

Good luck with it.

73-

NIck, WA5BDU

On Sun, Apr 14, 2019 at 12:59 PM Alfredo Mendiola Loyola via Groups.Io
<mendiola_loyola=yahoo.com@groups.io> wrote:

Hello:

I have found this Arduino code to set the Frequency on a si570 oscillator
but it has a max frequency of 157 Mhz (#define ULIMIT 157000000UL),

Is there a way to modify the source code to make it work until 440 Mhz ?

I would like to set frequencies from 430 to 440 mhz.

http://pages.suddenlink.net/wa5bdu/Si570_New.ino

Regards
Alfredo Mendiola
OA4AJP