Propeller DIP and Quad pack

at_jay

Dear Members!
I have successfully run a display program using propeller (DIP package) that was available on propeller professional development board. I failed to run the same program on another propeller proto board that uses quad flat propeller packagae.
I have used same I/O pins for output and input in both cases to make sure the perfect match..... Any feedback would be greatly appreciated.

Thanks
Jay

Duane Degn

I think we'll need more information.

Were you over-clocking the Propeller?

A schematic, code and pictures of the two set ups would be very helpful.

I've read that some forum members have had better success with over-clocking DIP chips than the other Propeller packages. I find it hard to believe there are many applications were the chip's package would make a much of a difference. I'd think the length of traces and wires would be a more likely source of performance variation.

at_jay

Currently I am running DIP prop @8x and Quad prop on same, so wondering where the difference is.... although length of tracks makes some difference, but what if the tracks are parallel and straight from I/O?

Tubular

I assume you are outputting VGA since you're using the proto board. Did you install the 3 VGA resistors on the proto board? Also it is worth trying PLL16x the 5MHz clock.

The track length and straightness doesn't matter.

Is it the USB version of the proto board? If so you have to provide separate power, despite the FT232 USB chip and its LEDs being powered by the USB from your computer, the rest of the board needs a separate power input to the USB jack. Are you able to load the program successfully, and write it to EEPROM?

Tell us more I'm sure we can get you up and running

at_jay

No I am using winstar 20x4 LCD display http://www.crestcomponents.com.au/wh2004ayyhjt-p-67.html.
I used 4 control I/O pind for R/W, RS, Enable and Back light display control while 8 I/O lines for parallel 8-bit data. It is quite straight forward design and is working on propeller professional development board. And yes I am successful in dowloading the program into Propeller proto board (quad) setup.

Tubular

Jay there will be a really simple explanation. I've run lots of DIP and QFP programs and had never had such an issue - its the same chip on the inside, only the packaging varies, and perhaps the number of power pin pairs (which shouldn't affect you anyway).

What I/O pins did you choose for your I/O? Is your display cable long or short from the propeller board?

at_jay

Its approximately same in length, for propeller professional board I am using test wires for each I/O while for Propelelr proto board I am using 16 way bus cable.

I/O 1--8, 13,14, 15 and 17.

Thanks.

Tubular

Jay, since the cable is different I would connect it all up and then check with a multimeter end to end for each of those pins you use to make sure they are reaching all the way from Propeller board to the the LCD itself.

If that 16 way bus cable is longer than 1 foot or so, and you're trying to drive it fast, the capacitance of the cable might be low pass filtering the data and strobe signals you send out. You could try running slower (PLL1x etc) just to see if it comes right again.

Also your bus I/O you say 1-8 - just remember the first pin on the propeller is "P0" and its common to hook an 8 bit bus up to P0~P7. You can of course use P1~P8 if you prefer, but I'm just making sure you don't have a simple offset in your program that could explain why it's not talking.