41 lines
1.2 KiB
Markdown
41 lines
1.2 KiB
Markdown
# Dev notes — 2023-09-05
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## Re: Blinkenlights
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See [2023-08-31](2023-08-31.md#displaying-data-microprocessor-trainer-style)
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That earlier note covers hexadecimal.
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Here are some new notes on decimal display:
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- https://en.wikipedia.org/wiki/Two-out-of-five_code -- used for representing the decimal digits using five bits.
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- https://en.wikipedia.org/wiki/Bi-quinary_coded_decimal
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- The Remington Rand 409 and UNIVAC LARC encodings listed on that bi-quinary page are close to what I might want.
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**Here's my bi-quinary variation (similar to the IBM 650's):**
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5 q q q q
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○ ○ ○ ○ ○ = 0
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○ ○ ○ ○ ● = 1
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○ ○ ○ ● ○ = 2
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○ ○ ● ○ ○ = 3
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○ ● ○ ○ ○ = 4
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● ○ ○ ○ ○ = 5
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● ○ ○ ○ ● = 6
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● ○ ○ ● ○ = 7
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● ○ ● ○ ○ = 8
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● ● ○ ○ ○ = 9
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## ISA
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I think the group and addressing-mode sections need to be smaller, so that you can have more than 16 distinct operations?
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## Naming/design variations
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- hex keypad version: “microcardiograph”
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- toggle switches “minicardiograph”
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- etc.
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(allowing diff design for larger punch-card mainframe...) |