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| metrologist:
I've acquired a MODEL DE/280A Digital Electronics Corp display. These are out there but I have not found a communication protocol or pinout. I think mine is a little newer than the pictures here but same chips and labeling. That main chip, DE280A, is there any hope of figuring it out? |
| metrologist:
I found some info: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1091816 The DE/280A accepts ASCII signals for the normal upper and lower case 96- character set and also for the expanded set, which, includes Katakana and selected ECMA characters. An on-board microprocessor handles decoding, character generation, display buffering, cu,rsor control, auto flashing of any or all characters, refresh, programmable reset, self-test, and a blinking visible or invisible cursor. All drive electronics are included along with necessary power conversion circuitry to adapt incoming +5 Vdc to tube voltages. Jumper selectable Bd rates (1200,2400, and 4800) are available for serial interfacing. Parallel interface is also standard. RS-232 voltage levels are optional. All character positions are randomly addressable. One additional feature of the DE/280A is that it is the same form, fit, and function as DECO's single-line 40-character module, the DE/245A. Consequently, either display can be used in a design without any changes in dimensions or user software. |
| DavidAlfa:
You could try reading the rom from the P8042AH. Check the datasheet, the verification sequence is explained, although it's a bit scary :D |
| metrologist:
That seems like the smart way to start. I wasn't even smart enough to recognize the chip number but at least the datasheet gives me some ideas of where to look for data pins, where my approach would be to inject some random serial data, or think I've found the parallel data pins and load up the LiquidCrystal Arduino library and... of course that would never get anywhere, no chicken dinner. I remember a video that Dave did on these vacuum displays though, and he figured out the data protocol. Wouldn't that be amazing if it was the same product? Unlikely, but I'll go look for his video. Otherwise, these are around the market and it seems a protocol could be found. I haven't found it. |
| metrologist:
Ah yes, here we go...maybe there is hope. At least I can still remember that I saw this seven years ago... |
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