Could you post the completed schematic & finished code you have used to get this working successfully. I too am looking for a volume control to put inline with a microns, controlled by an atmega chip.
The PT2256 datasheet doesn't tell you that for the -1db byte, there are only 10 steps, 9 - 0, not 16 like a nibble would imply.
PT2258_2.ino (3.26 KB)