Trouble with 4x20 LCD and propeller

LoLa

I have used the 4x20 LCD for the past few months with the BSpx just fine. Now I have moved to the propeller, and downloaded the sample objects from the LCD page. I don't have a 5MHz crystal, so I deleted those lines in the CON block, but didn't change anything else. When I load the program to the Prop, the cursor moves to the middle of the second line (about where I would expect "Hello, this text will wrap" to end), but there are no letters before the cursor. I tried loading the custom character object, and again, the cursor moves a couple characters over, but nothing else displays. I have confirmed that the LCD is plugged into the correcct Pin (0), and is set for 19.2Kbaud. What else am I missing or need to change?

Also, once it is working, is displaying another message as simple as calling the FullDuplexSerial.start method and following it with (string("message"))? Sorry for the newbie questions...just a big difference from the simple SEROUT command to the Propeller.

Thanks

Circuitsoft

I think the prop defaults to RCSLOW clock mode, which isn't fast enough to drive 19.2KBaud serial. RCFAST may be fast enough, but it might not be accurate enough to be accepted as 19.2KBaud by the LCD. Really, you need a crystal to talk to serial devices.

LoLa

I have a 20MHz crystal. From what I can tell from the Propeller manual, I just need to be at XTAL3 instead of one, and limit the multiplication factor to 4. Is that correct?

Circuitsoft

I don't think you can use the PLL with an input frequency above 8Mhz. If you use the PLL at all, it multiplies the input frequency by 16, then divides it down as requested, but the PLL can't go much faster than ~130Mhz.

LoLa

I tried a slower crystal and it works just fine. Thanks again!