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edits
User:Larz: Difference between revisions
From London Hackspace Wiki
→TRS-80 (Z-80)
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=== Cosmac Elf (1802) === | === Cosmac Elf (1802) === | ||
=== TRS-80 (Z-80) === | === ''TRS-80 (Z-80)'' === | ||
This was my first true hack. | |||
In 1978, the TRS-80 only displayed upper case characters. This was done to save one chip. With only 7 RAM chips in the video circuit, the system was limited to displaying the first 128 characters of the character ROM. | |||
I piggy-backed a 1K x 1 ram chip (that's 1024 bits - 2021A) onto the character generator circuit to allow all 8 bits of the character ROM to be accessed. A toggle switch on the side of the case let you turn the mod on and off. Not bad considering I was 14 years old and the machine cost $500. | |||
=== ''Commodore PET, VIC 20, C-64 (6502)'' === | === ''Commodore PET, VIC 20, C-64 (6502)'' === | ||
