Classic computing fanatic Cameron Kaiser has constructed a bit improve to MOS Know-how’s KIM-1 microcomputer — giving the traditional machine a “sidecar display” as a show system considerably higher than its inventory six-digit numeric LED show.
“[This is] a sidecar display for my KIM-1 that is massive sufficient to be helpful, sufficiently small to be moveable, and environment friendly sufficient to be powered by my unit’s built-in energy provide,” Kaiser writes of his creation. “Certain, you could possibly hook up a serial terminal just like the Silent 700 [but] which means lugging round two models — which looks as if a misplaced alternative as a result of this specific KIM-1 is totally self-contained with an influence provide and I/O [Input/Output] card in a tough plastic briefcase I can merely choose up and take with me.”
The MOS Know-how KIM-1 lastly has a show worthy of that 6502 processor at its coronary heart on this sidecar improve construct. (📷: Cameron Kaiser)
Launched in 1976, the MOS Know-how Keyboard Enter Monitor 1 (KIM-1) served as a starter package for the corporate’s 6502 microprocessor — and whereas initially supposed as little greater than a quickstart platform for engineers quickly discovered a distinct segment with hobbyists looking forward to a style of private computing. The inventory machine, although, lacked a bit within the niceties we have come to take without any consideration: its enter system was a hexadecimal keypad, and its show six glowing LED digits.
To enhance on that latter characteristic, Kaiser picked up a comparatively low-cost 20×4 character-based liquid-crystal show (LCD): the Matrix Orbital LK204-25. “I am chagrined to confess,” Kaiser notes, “as with so many different present-day retrocomputing peripherals, that the LK204-25’s onboard microcontroller is considerably extra highly effective than the KIM-1’s 6502.”
This overpowered show system got here with an RS232 connection, which was then level-shifted to the TTL stage required of the KIM-1’s general-purpose enter/output (GPIO) pins. Kaiser then set about making a second serial port in software program, which might feed information to the show with out tying up the machine’s built-in serial port.
Kaiser has discovered the show excellent for a spread of word-based video games, with extra ports deliberate. (📷: Cameron Kaiser)
“I believe the LCD provides specific worth to the KIM’s handful of phrase and textual content video games, neither of which is the essential unit’s robust swimsuit,” Kaiser writes. “I’d do another sport ports to the LCD; Hunt the Wumpus does a number of textual content show on the LEDs and can be a reasonably well-suited, if massive, enterprise. Nonetheless, I am already considering of upgrading the panel to one of many new LK204-25s.
“This could be costlier than what I’ve right here, however I might get the options of the 1.3 firmware, and with a TTL-specific unit I can eliminate the extent shifter and have a free 5V and floor line for another fascinating peripheral — and a free LK204-25 with a built-in serial port I may give to one thing else.”
The complete challenge write-up is offered on Kaiser’s weblog, whereas the supply code is printed to GitHub beneath the permissive two-clause BSD license — together with an adaption of Jim Butterfield’s Re-Verse sport, tailor-made for the show.