[Coco] CoCo 1/2 arrow keys versus CoCo 3 arrow keys

[Allen Huffman]

> On Jan 14, 2023, at 2:30 PM, Ciaran Anscomb via Coco <coco at maltedmedia.com> wrote:
> 
> You gotta be pretty careful about what keys you assign when there are
> multiple players.  The non-dioded keyboards mean multiple keypresses
> can "ghost" - when there are two players, if you don't pick your keys
> carefully, one player may interfer with another.

Is that from the keyboard matrix? I don’t think I knew about that, back then, but I learned when I was diving in to how to read the keyboard faster in BASIC. I noticed they made sure SPACE and ARROWS were different, perfect for cursor control and games.

For those who haven’t looked at it, the CoCo keyboard is a matrix. Suppose you have an 8X8 grid, and each square represents a key on the keyboard.  Any key in the same column or row will set that row or column. You can’t tell which key in the column is set, just that one is set. Thus, any keys that are on the same row/column cannot be used with other keys on the same row/column at the same time.

I drew it out on a blog post back then:

https://subethasoftware.com/2020/12/09/benchmarking-the-coco-keyboard-part-1/

--
Allen Huffman - PO Box 7634 - Urbandale IA 50323 - 515-999-0227 (vmail/TXT only)
http://www.subethasoftware.com - https://www.facebook.com/subethasoftware