Does anyone have experience with tempermental Digilent PMODs?
I have loaded the same test program onto both old and new Unos.
I have tested both with the same breadboard.
The Uno 3 does not successfully initialize the Digilent Pmod DA4. The old Uno does work, but stability is not perfect. I think it's now better with a decoupling capacitor, but the PMOD board should already have those.
One clue I have is that some folks mention that the DA4 is sensitive to power and has a lag time of possibly hundreds of milliseconds when it starts. I see that when I upload my code to my old Uno, the DA4 does not initialize; it's completely inert. If I then press reset a moment later, it initializes and runs.
Beyond that, I cannot explain why these 2 versions of Uno would behave differently. If I had not randomly tested my DA4 with the old Uno, I would have assumed it was damaged.