[TG-239] Add script to estimate closest divider ratios targeting a ce…

…ntral frequency (tomojitakasu#2)

python/max2772_pll_integer.py

@@ -0,0 +1,63 @@
+import sys
+
+# Compute the best divider values for a given target frequency
+Ftarget = 1573.42e6   # DESIRED TARGET local frequency
+
+### CONSTANTS
+Ftcxo = 16.368e6     # MAX2771 EVK is preconfigured to 16.368MHz TCXO signal
+
+# R-divider range
+Rmin = 1
+Rmax = 1023
+
+# N-divider range
+Nmin = 36
+Nmax = 32767
+
+# F-divider range
+Fmin = 0
+Fmax = 1048575
+
+Fint = 0
+Ncloser = 0
+Rcloser = 0
+for R in range(Rmin, Rmax):
+    for N in range(Nmin, Nmax):
+        Freq = Ftcxo / R * N
+        if abs(Freq-Ftarget) < abs(Fint-Ftarget):
+            Fint = Freq
+            Ncloser = N
+            Rcloser = R
+            if (Ftarget-Freq) > 0:
+                Ffrac = Freq
+                Nfrac = N
+                Rfrac = R
+        if Fint == Ftarget: 
+            break
+    if Fint == Ftarget: 
+        break
+
+# Integer mode closer results
+print(f'Target frequency: {Ftarget/1e6} MHz')
+print(f'  Integer mode results:')
+print(f'    Closer frequency: {Fint/1e6:.6f} MHz (offset: {(Fint-Ftarget):.6f}) Hz')
+print(f'      N: {Ncloser}')
+print(f'      R: {Rcloser}')
+if Fint == Ftarget: 
+    sys.exit(0)
+
+# Fractional mode final adjustment, if needed
+Fcloser = 0
+for F in range(Fmin, Fmax):
+    Freq = Ftcxo / Rfrac * ( Nfrac + F / 2**20 )
+    if abs(Freq-Ftarget) < abs(Ffrac-Ftarget):
+        Ffrac = Freq
+        Fcloser = F
+    if Ffrac == Ftarget: 
+        break
+
+print(f'  Fractional mode results:')
+print(f'    Closer frequency: {Ffrac/1e6:.6f} MHz (offset: {(Ffrac-Ftarget):.6f}) Hz')
+print(f'      N: {Nfrac}')
+print(f'      R: {Rfrac}')
+print(f'      F: {Fcloser}')