Foone🏳️⚧️
I've never used one, so can someone tell me how the Sinclair
ZX81 keyboard works?
Because I'm seeing like 5 options per key, and only one shift key.
Like the "S" key: It's Save, ARCCOS,. "S", LPRINT, and that graphical symbol. How do you select between those?
Foone🏳️⚧️
I'm not even sure how you type backspace on this. shift-0?
Foone🏳️⚧️
I have looked up the manual
this has made me more confused
philpem
@foone In BASIC, when it asks for a keyword, pressing the key gives you that keyword. The symbols are shift+key. I think the graphics characters are behind a shifted control code - shift-something for graphics on, and another combination to go back to text.
I vaguely remember my 128K having separate symbol shift and alphanumeric shift keys.
It's wild. Eventually you remember that JPP is LOAD"".
Foone🏳️⚧️
but the answer seems to be: it's a combination of shift and being modal.
The computer knows when you'd be typing BASIC keywords, so pressing "P" gives you PRINT in that case, no shift required.
you can also do shift-9 to get to graphics mode, which'll let you type the graphics.
and there's some way to get inverse text, but I'm not sure how. it doesn't have lowercase.
Foone🏳️⚧️
So at all types the keyboard is in one of these four modes:
K, L, F, or G.
K gets keywords (above the key), and the red text if shifted.
L gets regular text, and red text if shifted.
F gets the functions under the keys.
G gets the graphics.
Foone🏳️⚧️
You can't intentionally switch to K-mode: it's done automatically at the start of lines or when it needs numbers.
and confusingly, F and G modes work different:
you do shift-newline to get to function mode, but function mode turns off as soon as you press another key.
you do shift-9 to get graphics mode, but it stays in graphics mode until you press shift-9 again.
Foone🏳️⚧️
ahh, graphics mode is how you get the inverse text!
in G mode, regular presses give you the inverted uppercase letters, while shift+key gives you the graphics equivalent
Foone🏳️⚧️
now I just need to figure out how to map this to unicode and then also how to figure out how to actually type them because the HID keyboard protocol is a trash fire
Foone🏳️⚧️
unicode does have inverse squared letters, like 🅵🅾🅾🅽🅴, but the ZX81 can do inverse versions of all letters, and there's DEFINITELY not an inverse-square version of £
![Chris [list of emoji]](https://social.076.moe/avatar/260-48-20221215170436.webp){kind=small}
Chris [list of emoji]
Also, fun fact: all of the keywords were also characters in the character set. Which helps when you only have 1k of RAM.
Foone🏳️⚧️
@suetanvil I'm suddenly realizing that I'm re-implementing this keyboard on a microcontroller that's got 256 times as much ram as the whole computer it goes to
Chris [list of emoji]
Yes. At the start of a line, the cursor becomes an inverse-video "K" and pressing a key gives you the BASIC keyword in white text above the key. The cursor than turns to an "L" and lets you enter letters.
SHIFT inserts the red characters/keywords. I don't remember if it's modal or not.
SHIFT+NEW LINE puts the cursor in "function" mode and it will then insert the keyword below the keys; these are functions that can be used in expressions.
(ctd)
Chris [list of emoji]
SHIFT+9 puts it in graphics mode and lets you enter the special boxy characters next to the letter inside the key. Once again, I don't remember if it's modal or not.
EDIT (SHIFT+1) let you modify a line of your current program.
I don't remember how to do inverse video; I think it was something programmatic. They were done via a hack in the glue logic rather than being part of the character set.
(ctd)
Foone🏳️⚧️
my keyboard is ready for KEYWORD input
Foone🏳️⚧️
@6a62 they cut so many corners it's amazing their computers aren't round
joshie 🏳️🌈
@foone i would've said "oh go use the keyboard from that american market timex ts1000 thing" but i just looked it up and uhh... yeah they just re-used the original UK keyboard, £ and all
ah sinclair, always cutting every single corner imaginable
Foone🏳️⚧️
@tautology oh, I know it's awful: that's the point for why I'm using it
tautology
@foone Yes. It's an awful membrane keyboard. The Spectrum was even worse as that had more modifier keys.
Foone🏳️⚧️
okay I implemented switching between all the modes. I'm gonna take a break now, but the next step will be implementing ALL these fucking keyboard functions.
Den of Earth
@foone @th
(Four Yorkshiremen Sketch voice)
HAH! A keyboard - LUXURY!
We just had a number-pad with four shift keys!
Foone🏳️⚧️
@DenOfEarth @th YIKES
Foone🏳️⚧️
@growf Thanks!
Bruce Preston
@foone A 300 DPI scan of a ZX80/81 Reference Card from 1982: https://growf.org/stuff/ZX80-ZX81-Reference-Card.jpg
(Source: https://www.sinclairzxworld.com/viewtopic.php?t=1017)
Foone🏳️⚧️
@Landa I think they assumed (or hoped) that there were no ZX81 files still surviving
Landa :graz:
@foone I‘m surprised this is not in Unicode given that one of their stated goals was to allow round trip conversion between it and legacy character sets. :-(
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