Hi folks,
I noticed your postings, so I thought I'd add a response.
Firstly, a 6502 connection
Someone said it'd be on-topic if I it had a 6502 emulator. I toyed quite a bit with a 40-pin AVR-based full-speed 6502 emulator in the year before I developed FIGnition, because I wanted to hack it into the case of a Smith-Corona SL470:
http://oneweekwonder.blogspot.com/2010/ ... cking.html
The AVR 6502 emulator wasn't a pin-for-pin realisation of a 6502, but a combination of an realisation which could access external memory; a 6502 MCU with a built-in User port and built-in EEPROM Bootstrap ROM and a 6502 with access to the AVR's hardware features. Well, you can download it from here and read the comments. It assembles with the AVRA assembler.
https://sites.google.com/site/libby8dev ... ects=0&d=1
It assembles, but isn't tested at all. Feel free to use it, debug it etc, though please credit the source.
Choral Keyboards
The FIGnition keyboard has attracted more critical acclaim than any other aspect of FIGnition... with more criticism than acclaim admittedly
I'm aware of the FrogPad, it's good and I once considered buying one - I wish they still had the tactile one on their website, but the store only seems to show the Magic Frogpad
. There's quite a history of chordal keypads from the old Xerox alto chordal keypad:
http://research.microsoft.com/en-us/um/ ... .aspx?id=7
Then there's the Microwriter of course, which for me is the definitive chordal. There was also the fastap keypad:
http://news.bbc.co.uk/1/hi/technology/3123086.stm
which relied on using the cross-points between keys as an alternate key pad.
I had a number of design constraints if I wanted to produce a viable one of my own:
• I couldn't risk falling foul of anyone's patents.
• I couldn't afford many keys on the keypad (that is, it would add too much to the final product cost IMO).
• I couldn't afford a full Sinclair-style membrane keypad for the same reason.
• I wanted to retain some proportionality in the design.
• I didn't want to use a keyboard protocol, e.g. PS/2, because FIGnition is really about understanding principles and although PS/2 keyboard protocol has a practical value, it embodies no long-term principles outside of serial comms.
• I wanted to leverage mobile phone layouts to make it easier to learn.
My result, the FIGnition's keypad: let's call it the FIGgyPad, simply extends the concept of applying shift to every key on the keypad combined with a layout reminiscent of mobile phones. Easy to learn, simple to build, simple to write a driver for; cheap, practical and unpatentable. The keypad driver is in the currently released FIGnition source code on GitHub and both the hardware design and software are free to use and always will be (though copying the driver means crediting the author).
I take your point about the description and I'll think about how it can be better described, unless someone beats me to it.
The main thing
I've been interested in Microcontroller-based computers for quite a while, mostly because I'm interested in designing educational computers that can be built and understood and it's not fair to make newbies solder SMD devices. Unfortunately, it's actually harder to develop even 80s style micros today, because 80s components are harder to obtain and it's worse if you consider customer components (e.g. ANTIC / SID/ other early ULAs).
And even if you did; these kinds of machines are more of a minority interest than in the 80s so one has to wrestle with how to motivate people. In my mind then, using the MCU to directly implement the computer rather than emulating another architecture is my current compromise / refinement over projects like Libby8 and/or a 65AT2 system.
-cheers from julz