FE-5680A DDS helper: convert between frequency and tuning word.

fe5680.py

#! /usr/bin/env python3
import argparse
def freq_to_word(f_out, f_ref):
    N = round((f_out / f_ref) * (2**32))
    return N, f"{N:08X}"
def word_to_freq(word_hex, f_ref):
    N = int(word_hex, 16)
    f_out = (N / (2**32)) * f_ref
    return f_out
def main():
    parser = argparse.ArgumentParser(description="FE-5680A DDS helper: convert between frequency and tuning word.")
    parser.add_argument("--ref", type=float, required=True, help="Reference frequency in Hz ('N' value from DDS board's 'S' command output).")
    group = parser.add_mutually_exclusive_group(required=True)
    group.add_argument("--word", type=str, help="Convert Hex tuning word (truncated to upper 32 bits, e.g. 2ABB503D) to frequency..")
    group.add_argument("--freq", type=float, help="Desired output frequency in MHz.")
    group.add_argument("--freqhz", type=float, help="Desired output frequency in Hz.")
    args = parser.parse_args()
    if args.word:
        word = args.word.strip().upper()
        if len(word) > 8: word = word[:8]
        f_out = word_to_freq(word, args.ref)
        print(f"Word {word} = {f_out:.6f} Hz ({f_out/1e6:.6f} MHz)")
    elif args.freq is not None:
        f_out = args.freq * 1e6
        N, hex_word = freq_to_word(f_out, args.ref)
        print(f"{args.freq:.6f} MHz = Word {hex_word}")
    elif args.freqhz is not None:
        f_out = args.freqhz
        N, hex_word = freq_to_word(f_out, args.ref)
        print(f"{args.freqhz:.6f} Hz = Word {hex_word}")
if __name__ == "__main__":
    main()

output.txt

usage:
./fe5680a.py --ref <reference-freq-hz> [--word <F-value> | --freq <MHz> | --freqhz <Hz> ]

'S' command on my DDS returns me this:
R=50255056.377900Hz F=2ABB503DE5CA8C00
where R is reference frequency (tuned at factory), and F is the hex tuning word.

so what does mine say?
 ./fe5680a.py --ref 50255056.377900 --word 2ABB503DE5CA8C00
Word 2ABB503D = 8388607.989497 Hz (8.388608 MHz)

checks out. I measured 8.3886MHz or thereabouts when eyeballing it on my scope.

converting my fe-5680a to 10MHz operation? I would keep the R value (--ref) and calculate a new F (--word):

./fe5680a.py --ref 50255056.377900 --freq 10              
10.000000 MHz = Word 32F0AD87

and just to calculte it backwards to be safe:
./fe5680a.py --ref 50255056.377900 --word 32F0AD87
Word 32F0AD87 = 10000000.001753 Hz (10.000000 MHz)