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HP Forum Archive 14

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PLED/OLED display (OpenRPN)
Message #1 Posted by Hugh on 16 Apr 2004, 3:38 p.m.

It's a fairly recent technology, and I've had a devil of a time finding any. But I'm curious if anyone around here has any experience using them. Here's the place where I've found some OLED/PLED displays: As far as I can tell, these are really the way of the future, and I think they may be a good choice for OpenRPN.

I'm drafting up some basic CAD renderings at the moment, as I think it helps people to see things are actually materializing! Anyways, let me know what you think. I'll draw up a couple of good possibilities (16x1 and 16x2) and try to post them sometime soon.

I'm still having a bit of a pain getting hosting, but one of my friends may be able to donate some space for a while. If so, I'll have a site and nice php driven forum up next week!

Re: PLED/OLED display (OpenRPN)
Message #2 Posted by Nelson M. Sicuro (Brazil) on 16 Apr 2004, 4:16 p.m.,
in response to message #1 by Hugh

I like very much the OLED technology, but it is in an early stage of development, and its life span isn't very long. But those displays mentioned share the common interface with any other character LCD or VFD display, so it is easy to develop with one type and use another later.

BTW, I vote for a display at least 20x2 or 24x2, or a small graphic one like 42S' display. I have with me some matrix LED displays, without controller, and I'm building a prototype with them. It is a beauty! Soon I'll get some pictures. I'll create a controller for it using the very same interface used on those LCD character displays, for the sake of compatibility...

<thoughts on>
I think that the hardware part of this project will be very "assorted", and the software will need to deal with that. Once again, my idea is to create a "virtual" CPU that will run the core OS and applications, and the emulation layer will deal with any hardware we put on it. The virtual CPU will report its capabilities to the OS, and the OS enables or disables its features based on that "report", in a standard way. This way some of us can develop the emulator on any platform (PIC, MSP, AVR, PCs, Palm, etc) and others can develop the OS and applications - as soon as we define the CPU and OS API. This way we can have very good calculators on any platform we choose.
<thoughts off>

Best regards,


Re: PLED/OLED display (OpenRPN)
Message #3 Posted by Garth Wilson on 19 Apr 2004, 1:04 p.m.,
in response to message #1 by Hugh

PLED/OLED takes way too much current for a calculator. I looked at the spec. sheet online and then wrote them the following question:

"I was looking at the PLED/OLED spec.s and saw that it says 0.6mA for supply current. Since it is my understanding that this puts out light, I'm sure that is either a mistake or maybe only the current for the logic or something like that. Can you explain?"

Their response came this morning:

"Please find a graph of our current-sweep of one of our PLED displays here:

The maximum current used was less than 45mA for logic+brightness. It is likely that the .6mA is for the controller only."

The graph shows that typical text takes 10-19 mA, and the module may take up to nearly 45mA max. I expect it's still not sunlight-readable either like reflective LCDs are.

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