I noticed I didn't have an introduction online in this thread yet...
For my first experiences with computers, I'll refer to my post in the Nostalgia forum from yesterday:
viewtopic.php?f=3&t=2805&p=31044#p31024Short version and additional info:
I grew up in the Netherlands, and met the PET-2001 in 1978 when I was 11. I played around with it, and with a CBM-4032 at my high school, until we got an IBM PC at home and I graduated. I always remained interested in the 6502 but I never owned a 6502 system in the 1980s or 1990s. I do remember spending a vacation in France reading all the Elektor Junior books, and someone once asked if I could reverse-engineer and update a 6502-based ventilation controller which I started on but never finished, that's about it.
It took until 2008 or so (after I emigrated to the USA) until I found out that there were so many retro and 6502 enthusiasts online, here and elsewhere. I bought a MicroKim from
http://www.brielcomputers.com and helped my stepson solder it together, which was a lot of fun. And I found out that I live in the city where Western Design Center has their office, and I must have passed by it hundreds of times without even knowing about its existence, when my wife worked at a job on the same street.
Almost 3 years ago I started on a project called Propeddle (
http://www.propeddle.com) which will be a kit that lets a Parallax Propeller bitbang a 6502 at 1Mhz. This should make it possible to emulate early 6502 computers such as the KIM-1, SYM-1, PET/CBM and many others that didn't use custom chips. It should also let you create new "Software Defined" 6502 computers that never existed as hardware before. Having a Propeller will help with the bringup of a system: Even if it's not connected to a PC via a serial port, the Propeller can run a program that lets you use the video and keyboard to inspect and modify any ROM images that it will expose to the 6502; it may even be possible to put an assembler/disassembler on board to sort-of create your own 6502 computer bring-up hobby kit.
At the time of this writing, Propeddle apparently almost works: I can run the 6502 at 0.9MHz (88 Propeller clocks per 6502 cycle) but when I run it at full speed (80 clocks), something goes wrong; I will need to hook it up to my logic analyzer to find out what it is. I also have to re-write some of the software including the part that uses the NMI on the 6502 to download data from the Propeller to the RAM. I also have to design a new circuit board: the current PCB requires a Propeller Platform motherboard and a Propeller Platform video/keyboard interface that has to be modified because I use non-standard pins. But not only is the Propeller Platform more or less discontinued; there were also practical problems like the need for expensive, hard to find, stacking connectors. The new PCB will have everything on one board (Propeller, EEPROM, WDC65C02S, RAM, glue logic, connectors for expansion, TTL serial port, keyboard (PS/2) and video (TV and VGA). I may also make a "low cost" kit that will require a Quickstart (
http://www.parallax.com/product/40000). I also have some ideas for hardware expansion with an SD card reader and/or a second Propeller, for the systems that are more difficult to emulate because they have custom chips, such as the C-64 or Nintendo.
The reason that I'm not making much headway with my Propeddle project is that I don't have a lot of spare time and I also have some other projects I'm working on, one of which is the OSI Superboard Replica project by Vince Briel (
http://www.brielcomputers.com/phpBB3/vi ... =36&t=1515). I met Vince at the Bay Area Maker Faire in 2012 and we talked about his projects and mine; we exchanged some information and I helped him integrate some of my ideas into his schematics and software which made the emulation more precise, and reduced the number of components (for example, no EPROMs are required: the Propeller emulates the ROMs). The OSI replica will basically be a specialized version of the Propeddle project. Meanwhile, I also learned from his ideas, and learned a lot about the Ohio Scientific computers (of which the UK101 was a clone) which are very simple but surprisingly versatile!
===Jac