The story
The 8085 computer has been a standing project in the lab. Based on work from previous years, students are called to utilise the knowledge they've acquired during the first semester (which I did not take) to construct the computer based on the schematics provided. Furthermore, each group is assigned a side-project, which usually is the addition of one of a few peripherals available, such as a keyboard, character LCD or, alternatively for the most daring, a full-graphic LCD, external sensors and so on.
My story was a bit braver, though. Not having attended the first semester of Microelectronics, I decided to take the second half of the course and see what happens. I originally was the third member of a group (which are always comprised of two) but I soon decided to go on my own. To make things worse —or better, depending on which side you look at it— the schematics we were given were wrong.
Fortunately, I never looked at them but relied on a basic logic map and the datasheets of the components. That added a little more to my accomplishment. Pursuing a different wiring strategy than the rest also made an impact, as did the fact that my board worked from the beginning, without any corrections.
Finally, that project got me a straight 10 that semester, but that was not the best I got from it. Being able to pull this off, it made my reputation in the Electronics Lab and paved the way for more.
Thank you, little 8085!
Components
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NEC 8085 | Processor |
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AMD 2764 | 8KB EPROM |
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Hyundai 6264 | 8KB SRAM |
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OKI 8255 | Parallel interface |
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Intel 8279 | Keyboard interface |
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Intel 8251 | Serial interface |
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Intel 8253 | Interval timer |
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Motorola MC14411 | Bit rate generator |
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Maxim MAX232 | RS-232 transceiver |
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National Semi 74LS374 | Octal latch |
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National Semi 74LS138 | Demultiplexer (x2) |





