uOLED 96 prop problem getting started

joeld

I'm apparently making some very basic mistake getting started with the uOLED. I'm also new to the propeller and thought this would be a good hardware platform to experiment on.

I wired up the uOLED and it ran the demo just fine. I attached a prop plug and that also worked fine. I'm assuming that because it would identify the hardware. Selecting Identify Hardware seemed to also cause a reset of the uOLED.

I downloaded the Demo v4 file, the uOLED driver and the latest Clock files off the parallax website.· I opened all three in the propeller tool, set the Demo file as the top file and compliled. All compiled without error. Then I compiled to RAM. The uOLED device blanked and stopped working. I tried this several times. Identifying hardware or a power reset would bring it back no doubt reloading the original software from eeprom.

Then in a less then briliant act I complied to eeprom and now it's completely dead. I'm obviously loading up bad software. Am I missing something obvious??

Thanks

Mike Green

Try downloading uOLED-96-Prop Basic from the Propeller Object Exchange, then download it to your uOLED. This is another program for the uOLED that's known to work. There's a pre-compiled binary file included that you should try first.

Duffer

joeld,

CAUTION! The Prop Plug will not work directly with the uOLED-96-PROP. The 5 pin interface of the 96-PROP is different from the 4-pin Prop Plug interface. You could damage the display, the Prop Plug or both it you try to plug the Prop Plug directly into the 96-PROP interface.

Take a closer look at the interface pin outs for both devices.

Steve

joeld

I used the prop plug documentation for hooking it up. I did swap the required lines. I'm thinking that part is working. Would it return a "prop found" if the pc and uOLED weren't talking correctly. I'm assuming some data gets transferred back.

I will try and download the binary file and see if I can get it back up and running. Thanks for the suggestions.

joeld

Well, I restarted my laptop, added a bypass capacitor across vss and vdd. (I just have the uOLED on the prop breadboard) Now everything works just fine. I'm not sure what really fixed the problem. Makes me wonder how stable the uOLED is. I can write to the ram just fine.

I guess we'll see how long this lasts.

joeld

I came back after a few hours and powered the uOLED back up and it was dead again. I tried pulling the rst pin low and high with a resistor and it came back to life. Could it be that the rst pin is floating to some unknown state with just the prop plug attached to that pin? Should there be some external circuit i.e. capacitor and resistor on the rst pin to hold it low when power comes on?

Goran (Sweden)

Joeld,
Could it be you need higher supply voltage.
The 4dsystems forum says min 3,6 volt
see link: http://www.websitetoolbox.com/tool/post/4d/vpost?id=2459038
Also check for pullup on the uOled RX.
There are more usefull info on the 4dsystems forum.

Timothy D. Swieter

joeld -

What is the clock speed you are using in the downloaded programs? Some of the 4D System code run the Propeller passed it datasheet ratings. I understand that works on some of the devices, some of the time. You may need to reduce the overall clock speed of the system from 128MHz. to 64MHz. by adjusting the PLL.

Good luck, the uOLED-96-PROP is a great product and is an excellent way to start with the propeller.

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Timothy D. Swieter

www.brilldea.com·- check out the uOLED-IOC, an I/O expansion for the uOLED-96-PROP
www.tdswieter.com

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One little spark of imagination is all it takes for an idea to explode

joeld

For the most part I was having good luck with the uOLED-96. After it had sat with the power off for long periods I still had trouble getting it to power up. It had to sit with power on for a while before it would reset.

I dug around on the 4D forum and found a thread that helped. It said a pull-up resistor is required on the display's rx pin so it wont float during boot up. I added that an haven't seen the problem again. I never saw that on any of the schematics.