uOLED-128-GMD1 Paperweight?

Sniper King

So, I have been messing with the uOLED display from 4D Systems.· It will come up in the scrolling demo mode just fine.· Then I run the uOLED demo propeller software and it resets the demo without scrolling and sits there.· Recompile... same.· Same thing happens with the jumper on or off.· Bad unit?· Maybe, but I have 2 of them and they do the same thing!·

I have checked and rechecked the wiring including TX to RX and so on.· Nothing works.· Then out of no where it will work.· Then stop again.· I am losing it here!·

Any help would be great!

Michael



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·- Was it pin 11 or 26?· Hmmm....··I think the smell of smoke tells the whole story.· Must be 26.



Michael King
Application Engineer
R&D
Digital Technology Group

Rayman

Isn't there a PC program you can use to test the uOLED-128-GMD1?· You might try that to make sure the display is working...

If your trouble is serial communications from you Propeller, you might check things like making sure you have the right crystal frequency selected...

You could try a Hyperterminal session with a PC to see if your serial comms are working right...

Sniper King

Thank you! i hook the darn thing up to my prop usb programmer thing and it worked. What I found was to add a 10K resistor to the reset pin and ground. This effectively created a nice low state.

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·- Was it pin 11 or 26?· Hmmm....··I think the smell of smoke tells the whole story.· Must be 26.



Michael King
Application Engineer
R&D
Digital Technology Group

Duffer

It's more likely that you need a pullup (10K works) on the display's Rx line. If the display sees "noise"·on its Rx line during the propeller power-up, as can happen with pins that float during that time, The display will sometimes lock on to the noise thinking that it's an AutoBaud request and will then not accept serial commands.·This happens often enough that the documentation has been changed and the new uOLED-128-G1 and uOLED160-G1 displays have a built-in pullup on the Rx pin, a current limiting resistor and a protection diode to make them more 5V tolerant.

I'm surprised that pulling the RESET pin down to GND didn't cause you problems. The RESET is active low. Taking the pin low for >10uS resets the display.

Duffer