IT LIVES!
So it works. At least almost entirely. I accidentally ordered the wrong package type for the binary counter, but that part is just desert - the meat and potatoes - the DAC - works just fine. If I apply a high voltage to the pad where the third bit outputs, corresponding to 100, I get approximately 1.7A out. If I apply a high voltage to the first bit, i.e. 001, I get approximately .5A out. If I apply a voltage to the second bit, 010, I get about .8A out. Any combination of these will literally just add the currents. So if I have the binary counter outputting 110, it will output 2.5A. If it outputs 101, the driver will output 2.2A. So, my current ranges are:
001 - 0.5A
010 - 0.8A
011 - 1.3A
100 - 1.7A
101 - 2.2A
110 - 2.5A
111 - 3.0A
So there are all my modes
Who needs programming? Heh.
Also, another good bit is that the little MOSFET there, at the bottom?
That is the switch. So no high current needs to go through ANY of the buttons! Wewt! Also, those four pads at the top are supposed to control the binary counter, and it will work - I've made sure of that. When a switch connects the top two pads, it'll increment the current by one step. If a switch connects the bottom two pads, it'll decrement the current by one step. Neat, huh?
Anyway, I am going to order the CORRECT binary counter today and hopefully get it by the end of the week so I can get it wired up inside the host!