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Why the Apple II Didn't Support Lowercase Letters (2020)

(www.vintagecomputing.com)
136 points colinbartlett | 1 comments | 10 May 25 21:15 UTC | HN request time: 0.247s | source
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WalterBright ◴[10 May 25 22:48 UTC] No.43949649[source]▶
Back in 1978, I made my own keyboard for a single board 6800 computer I designed, also because I could not afford a keyboard.

I went to a surplus store and bought an EBCDIC keyboard for a couple bucks. I unsoldered all the keys from the circuit board. I took a plastic board, and using the old circuit board, drilled holes in it. Inserted the keys in the holes, and then wired it up in an 8x8 grid pattern. The two 8 bits gave 64 possible keys, which was enough, connecting those to an I/O port enabled recognizing which key was down.

It worked fine as long as you were careful not to press more than one key at a time.

I don't recall what I did with that computer. It's all gone, including the design notebook for it.

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Dylan16807 ◴[10 May 25 23:48 UTC] No.43950004[source]▶
Could the code subtract out the previous key for two overlapping key presses, or was it a very strict one at a time?
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throwanem ◴[11 May 25 00:16 UTC] No.43950134[source]▶
If I had to guess, the sixty or so diodes required for an NKRO matrix might have blown the money budget for the project, about like trying to do that kind of work in an interrupt handler would blow the cycle budget for any interesting program even had it been possible. Typing more slowly is free.

Hard to say. I would need to look up component prices for a few years prior to my birth, and it would take me a few minutes to find that archive of 70s Radio Shack catalogs again - though I believe it was actually posted here, so. Of course anyone serious enough to be building an entire computer in those days, brilliant keyboard hack and all, probably wouldn't be sourcing a jellybean part like 1N400x signal diodes one by each...

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WalterBright ◴[11 May 25 01:06 UTC] No.43950371[source]▶
The keys I used weren't jellybean. They were excellent keys. They were in the surplus bin because EBCDIC keyboards were already obsolete by then.

I had very little money at the time, and scrounged for parts.

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1. throwanem ◴[11 May 25 01:33 UTC] No.43950510[source]▶
By "jellybean" I meant the sort of small signal diodes one might use to prevent aliasing in a keyboard matrix. I know where I'd have gone to get those in my twenties, but not really how I'd have afforded that many for one project, even at the (very) small discount they might have given me on an order of that size.

Unfortunately, now that I've finally reached a point of being able to really effectively use such a resource as that store, in its place now stands a Sonic drive-in. So it goes.