No Arduino on hand, as far as I can remember. I've got all manner of stuff crammed away, though, so it's possible. Heck, if that made it work I'd just switch since I don't have any real code invested yet. :) (Edited to add: Looks like I do have an Arduino laying around; it's part of an unfinished project to convert an XBox 360 Rock Band guitar controller signal to be usable on a PS2 GuitarFreaks/Drummania game. Got it mostly working with the wired version, but was trying to make wireless work using the USB PC dongle. Not really relevant to this discussion, but figured it might score some geek points. :) I'm not sure where the code for that is living right now; I'll need to track it down so I know I can go back to that project in the future before I rip it apart to do testing on this one.)
Ultimately, I'll be including an XBee shield in this part of the project, but that's not necessary at the moment, so I've removed it just to eliminate another variable. I'm including photos as links so I don't overload the forum with huge pictures.
Power Connections: I've got four D cells (6V total) providing power to both the Netduino and the PWM board. Grounds connected to grounds, hot line going to VIn on the Netduino and screw terminal V+ on the PWM board.
Netduino Connections: Pins from the Netduino are connecting to the PWM board through an 8 position ribbon cable I had on hand. Connections are as follows: 3.3V -> Pin 5 (Vcc), GND -> Pin 1 (GND), A6 -> Pin 3 (SCL), A5 -> Pin 4 (SDA). Incoming battery connections are also visible on another GND pin and VIn.
PWM Board Connections: Incoming ribbon cable connected to one of the side headers, terminal block wired to battery. Two ribbon cables lead to the LEDs, one connected to the PWM positions, one connected to V+. (Note that two of the interior wires on each cable are disconnected because of the spacing of the pins.
LED Connections: The ribbon cable connected to V+ is connected by jumper wire to the + rail of a protoboard. The PWM ribbon cable is connected to one leg of the LEDs, with the other leg on the + rail.
All LEDs On: When everything is powered up, all seven LEDs are on constantly, where I would expect them to blink on and off, switching state each second.
After staging the setup for these photos, I put the analyzer on the wires again to verify it was still acting as before. I was able to capture two full sets of commands. The first set started at 80ms into my trace, ending at 150ms. The second set started 1150ms, ending at 1220ms. That lines up nicely with the 1000ms sleep between commands. First set all were of the form S, 0x80, A, 0x06, A, 0x00, A, P, for registers 0x06 through 0x45. (The trace actually seemed to miss quite a few of the clock pulses; may have been due to my sampling rate, as it got many cleanly, then started missing several before picking them up again.) Second set sets registers 0x06 through 0x09 to 0x00, 0x00, 0xA0, and 0x0F, respectively, then repeats that pattern through the remaining registers.