Grumpy_Mike: First off do you get the default rows with no other input? Next change the numbers that initialises the ledBuffer, are these change reflected in what you see on the LEDs?
Yes and yes. When I first turn it on I get a row of red, blue, green and a kind of light pink. When I change the values in the sketch and re-upload the changes are reflected on their respective rows.
Grumpy_Mike: Now change the wiring so that only one cathode is connected into the TLC5940, that is only have one LED per column on one of the rows. Can you change those numbers in that one row and see the effect?
I'm not sure if I totally follow this one. I removed three of the LEDs from the first column and the color of the remaining LED changes just as the whole row did prior to removing the other LEDs.
Grumpy_Mike: I looks like you have not wired up something correctly, what type of FET have you used, it should be logic level P-type, and check that you have identified the drain and source correctly.
I'm using a p-channel FET from sparkfun. Datasheet: http://www.sparkfun.com/datasheets/Components/General/FQP27P06.pdf I think I've got it hooked up according to your schematic but it's entirely possible I misunderstood something.
I've hooked up like so:
- 1 wire going from D to a row of the LEDs' common anode.
- A 4.7k resistor going from S to G
- 1 wire going from S to 5v (after the resistor)
- 1 wire going from G to Pin XX on Arduino (after the resistor)
Here's a screen shot from Fritzing: