From Heritage/1 to LC-81
The dificult decision was finaly made
10/13/2010
Realizing that my spare time is getting more and more scarce, I put together a detailed list of all individual tasks pending for this project to sadly learn that it would take much longer that previously thought... about another year!
As other priorities came to my life I finally made the decision that I was trying to avoid: to put this project in "sleep mode" for an undetermined period of time.
I have to be honest: I feel like having divorced... However, a good thing about designing an old computer is that she never gets old, so I should be able to take it back some day, maybe when I retire.
LC-81 to the rescue
10/24/2010
Heritage/1 has been (and still is) a loved project; the only problem is the enormous amount of time and mental attention it demands from me. I was wondering what about to take something less demanding in terms of hardware design such as one based on an old microprocessor such as the Zilog Z80.
It is a totally different story, of course, but at least I could build a "basic hardware" in short, so I could devote the rest of the time to the second half of the matter which is Software and peripherals.
My problem with these kind of projects is that I take them very seriously in terms of "culture" and I've set my mind already around the "minicomputer culture".
Not entirely convinced yet, I nevertheless gave it a try. I called it "LC-81" to signify: a "Learning Computer", 8-bits, try 1.
Ready to wire
11/15/2010
LC-81 is a Mini-Computer based on Zilog Z80 microprocessor. I've missed the excitement of designing the CPU but gained, in return, a very fast development pace. In fact, the LC-81 "CPU Board" was designed in three weeks in contrast to Heritage/1 which took me one year to (partially) design the CPU circuits.
I also built the shassis for the "Lab implementation" of the machine. Here is a picture:
Now I'm ready to start wiring the boards starting with the "CPU Board" which contains the microprocessor, the first 16 KB of memory, bus buffers and some other logic.
A final words
11/30/2010
Heritage/1 is not dead, she's only sleeping as the Sleeping Beauty would... waiting for a prince with time!.
I believe that LC-81 will allow me to go faster in obtaining the experience necessary to tackle Heritage/1 in the future.... did I say correctly, future? Am I not building machines of the past?
I will stop posting notes on this site. Notes for the LC-81 project are in here:
http://www.armandoacosta.com/lc81/
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