From 6d112b6e79c95283d3b03ab82a53a68d0327abc4 Mon Sep 17 00:00:00 2001 From: n loewen Date: Tue, 5 Sep 2023 11:07:38 -0700 Subject: [PATCH] 2023-09-05 - Create note. Bi-quinary, plus quick notes on ISA and naming. --- 2023-09-05--dev-notes.md | 41 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 2023-09-05--dev-notes.md diff --git a/2023-09-05--dev-notes.md b/2023-09-05--dev-notes.md new file mode 100644 index 0000000..37ba8aa --- /dev/null +++ b/2023-09-05--dev-notes.md @@ -0,0 +1,41 @@ +# Dev notes — 2023-09-05 + +## Re: Blinkenlights + +See [2023-08-31](2023-08-31--dev-notes.md#displaying-data-microprocessor-trainer-style) + +That earlier note covers hexadecimal. + +Here are some new notes on decimal display: + +- https://en.wikipedia.org/wiki/Two-out-of-five_code -- used for representing the decimal digits using five bits. + +- https://en.wikipedia.org/wiki/Bi-quinary_coded_decimal + - The Remington Rand 409 and UNIVAC LARC encodings listed on that bi-quinary page are close to what I might want. + +**Here's my bi-quinary variation (similar to the IBM 650's):** + + 5 q q q q + + ○ ○ ○ ○ ○ = 0 + ○ ○ ○ ○ ● = 1 + ○ ○ ○ ● ○ = 2 + ○ ○ ● ○ ○ = 3 + ○ ● ○ ○ ○ = 4 + ● ○ ○ ○ ○ = 5 + ● ○ ○ ○ ● = 6 + ● ○ ○ ● ○ = 7 + ● ○ ● ○ ○ = 8 + ● ● ○ ○ ○ = 9 + +## ISA + +I think the group and addressing-mode sections need to be smaller, so that you can have more than 16 distinct operations? + +## Naming/design variations + +- hex keypad version: “microcardiograph” +- toggle switches “minicardiograph” +- etc. + +(allowing diff design for larger punch-card mainframe...) \ No newline at end of file