Hi,
Just a tip, sometimes, using 4-bit mode...leaving D3-D0 unconnected causes problems, I think this is down to the LCD, but I don't know why people leave them unconnected...floating inputs is just a bad idea. Connect the unused inputs to GND. it can't hurt, it just stops them floating and picking up god knows what noise when you're setting up for 4-bit mode (so it ignores the lower nibble).
Is your micro running at 5v as well? Not sure if 3.3V I/O's would cut it on a 5V LCD.
As for Contrast, any preset will do, preferably 10k+, its just a voltage divider, and the Vo contrast pin hardly draws any current at all. You could add a 100k resistor in series with it (VCC side) to use the full range of the pot (usually anything above 1v to Vo is useless). When you've powered it up and initialiased it...give the pot a wiggle.....16x2 lcd's have a test pattern where the *top* line is just black blocks (unless the LCD is negative
)....if the contrast is set too low, ALL blocks will be black. because your LCD is 16x1 the test pattern will look >>the same<< as if the contrast is set too low. I doubt thats a problem anymore though. Also, the 'RS' pin is command/data. Pulling it high will (if I'm not mistaken) only allow instructions to be written, so the best you'll get there is a blank screen (no black blocks) because you can't write data for it to dispaly, which is useful for debugging. But...as I mentioned above...you'll get the black blocks if the contrast is set too low.
To be honest, I've spent ages debugging an LCD circuit before, and in my case, its always been hardware, just silly mistakes like wrong connections. Connect everything that needs to go to GND, then the VCC pin, then contrast (Vo) so you're just left with the 4 data lines, R/W, and E. Then connect them up, fire up your micro. If you've checked everything several times, its software.
As for your micro not being 'compatable' with the LCD, I seriously doubt it.
Let us know how you get on.
Blueteeth.
Ps: Sorry if I've repeated some stuff that Nigel has suggested, don't wanna steal anyones thunder, he's probably the best person to ask about micros+LCD's anyway.