User Interface, Using A buffer with a module

You also have to look at what the TEA5767 Module is expecting as a representation of the frequency.
Have you a code sample of feeding the TEA a specific frequency ?

I'm just looking at something I found/wrote some time ago now.
The frequency is calculated in an unsigned integer and then is split into two unsigned characters.
There may be other ways of doing the same thing.

  Wire.beginTransmission(0x60);   //writing TEA5767
  Wire.write(frequencyH);  // unsigned char
  Wire.write(frequencyL);  // unsigned char
  (bHLSI) ? (Wire.write(0x10)) : (Wire.write(0x00)) ;
  Wire.write(0x10);   // XTAL
  Wire.write(0x00);
  Wire.endTransmission();

Edit:
I found it here . . .
https://www.electronicsblog.net/arduino-fm-receiver-with-tea5767/