Classic computing fanatic Cameron Kaiser has constructed somewhat improve to MOS Expertise’s KIM-1 microcomputer — giving the basic 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. “Positive, you would hook up a serial terminal just like the Silent 700 [but] which means lugging round two models — which looks like a misplaced alternative as a result of this explicit KIM-1 is totally self-contained with an influence provide and I/O [Input/Output] card in a tough plastic briefcase I can merely decide up and take with me.”
The MOS Expertise 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 Expertise Keyboard Enter Monitor 1 (KIM-1) served as a starter equipment 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 somewhat 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 function, 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 degree 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 may 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 explicit worth to the KIM’s handful of phrase and textual content video games, neither of which is the fundamental unit’s robust go well with,” Kaiser writes. “I would do another sport ports to the LCD; Hunt the Wumpus does plenty of textual content show on the LEDs and could be a reasonably well-suited, if massive, endeavor. Nevertheless, I am already considering of upgrading the panel to one of many new LK204-25s.
“This could be dearer than what I’ve right here, however I would get the options of the 1.3 firmware, and with a TTL-specific unit I can do away with the extent shifter and have a free 5V and floor line for another attention-grabbing peripheral — and a free LK204-25 with a built-in serial port I may give to one thing else.”
The complete mission write-up is offered on Kaiser’s weblog, whereas the supply code is revealed to GitHub underneath the permissive two-clause BSD license — together with an adaption of Jim Butterfield’s Re-Verse sport, tailor-made for the show.