6502.org

This post might seem to be all about me, but it could be an idea which anyone can follow: what's your story so far, what's changed, what have you learnt, since joining this forum.

So, I noticed recently that I've now passed my tenth birthday here on this forum, and I think I'm right in saying that it was here that I first stopped being a lurker and became a poster. So although I've been online for longer, in a sense it's only been ten years of activity online.

And noticing that caused me to reflect and wonder what's happened, what's changed, and what have I learnt. And indeed, what have I done. And thinking about it, almost everything I've done has been a collaboration, usually with me in an assisting role, which is fine. I think it's all been open source too. By far the most of what I've done, I think, is to commentate, and speculate, and give feedback, and provide pointers, and hopefully that's usually a positive thing.

One thing that's changed, of course, is the cast of players. When I turned up, Sam (kc5tja) and Toshi (TMorita) were quite active, and they've mostly moved on. And Bruce (dcxlvi) similarly. Nightmare Tony and Leeeeee are no longer with us in a more permanent sense. But Garth was already there, as was Daryl (8BIT) and Andrew (BitWise), and Mike was always present, if not a frequent poster. I'm sure there are many more - this is not meant to be an exhaustive list!

Another thing which has changed is the availability and capacity of programmable logic. We've had CPLDs and then FPGAs, and those have got bigger and cheaper. We can now simulate and implement surprisingly large designs. CPLDs are great for mopping up glue logic and also providing some configuration registers or simple peripherals; FPGAs were already big enough for a 6502 when I turned up, whereas now even a cheap one is big enough for a whole 8-bit microcomputer.

And PCBs have gone from being expensive and quite slow to arrive, to being cheap and quite quick to arrive - at least for modest projects.

I think through-hole and 5V has been on the wane throughout those ten years - 3.3v designs and surface mount parts were already common enough in 2009, but it was easier to do everything old-school at that time.

It looks like using microcontrollers to act as glue, or as smart peripherals, was already being done when I turned up, so that's no change!

Computers have got faster, and browsers even more so, so we now have some very interesting things running on JavaScript: JSBeeb and easy6502 to name but two, and many more in Frederic's list which I help to curate. Including the visual6502 and its remarkable siblings, the visual6800 and visualARM. And several 8 bit IDEs.

What have I learnt? Well, a lot about the 6502, and a fair bit about the practicalities of making a working design. And some things about the dynamics of online communities - this place being one of the most positive and supportive, and stardot being another. I might have learned a bit about computer architecture and reverse engineering. I've learnt a lot of computer history, which has become a major interest.

And of course I've met new friends, which is always good.

What have I done? Well, Beeb816 was the first, I think, and very much a collaboration with me in a secondary role and Rich (revaldinho) in the lead. a6502 was much more my own work - you can tell from the code quality - but built on Chris Baird's and on Ian Piumarta's projects. 65Org16 built on Arlet's core and Nick's easy6502 emulator and came from a broad discussion thread. Electric_EyE took it further than I did. My part in Visual6502 was somewhat after the fact, but I'm going to claim it anyway! That's grown well beyond 6502 and is a great credit to Barry, Brian, and Greg. I've done some assists on py65, and some twiddling with this site, both thanks to Mike accepting contributions. PiTubeDirect has been a splendid success, and is mostly Dave's work with lots of optimisations from Dominic. The "mos6502" pages on gplus were André's invention but I've done most of the recent posts and summaries. Veering away from pure 6502 interests, the "Retro Computing" community on gplus was Chris' creation but I've done most of the recent moderating, with help from Norbert. Like any community or forum, it's the members which make it work. And anycpu.org was Dajgoro's creation. The OPC series of CPUs by revaldinho was and still is an interesting adventure. And I've spent many happy hours in Dave's (hoglet's) lab discussing, investigating, and sometimes fixing and building things. His recent HDMI output dongle is a notable recent achievement, and fitting up Arlet's 6502 core as a 65C02 was a less recent one.

I'm sure I've forgotten some things and failed to mention some people.

I used to say that I manage about one productive weekend a year, and that's still about right, so it should account for about ten things over ten years. Here's to the next ten!

(Oh, I see both Dr Jefyll and BDD celebrate their first ten years here this year - perhaps we'll hear from them. Oh, and double Oh, I notice whartung and Ruud are just over fifteen!)

Thanks for the feedback, BigEd. There's a vast wealth of experience here and while I consider myself relatively au fait with the 6502, there's always more to learn and I think there's something to learn from everyone who's posted here, or at least given me pause for thought.

One thing you mentioned- PCBs - so ~30 years ago I was playing with simple CAD programs, letraset, laser printers, acetate sheets, photo-resist boards, caustic soda and ferric chloride... And when I left that environment I stuck to strip-board, but about 6 years ago I decided to see what the state of the art was ... And was completely blown away. So now while I still like using strip-board, I'll also make a PCB up and it's back from China in a reasonable time and at a very good price - and I'm sure I'm like a lot of people and would like to buy local, but UK/European prices for PCBs are just way OTT.

So... (my) The Story so-far...

A relative newbie here - looks like I'm just over one year here now, although I lurked for a long while before registering, so it seems much longer...

Last year saw my 40th year as a programmer of things - with the 6502 being the first microprocessor system I used on an Apple II at school in Edinburgh in 1978. Experiences since then have seen me doing a lot of interfacing and building SBC type systems (mostly 6502), robotics, factory-automation, and a multitude of things including the weird world of supercomputing and The Internet... In recent years doing lots of stuff with the Raspberry Pi and Arduino type things - mostly to do with interfacing but I also achieved another personal project which was to write what I considered my "ideal" BASIC interpreter (which I've even sold and continue to sell programs written in it)

Now I just want to play with the old stuff again, so to that end I created my little Ruby (40th anniversary) board with no real aim for what it might do, but I've had a lot of fun with it - it falls into the "microcontroller supported" board - in that it's ROMless and uses the microcontroller (ATmega1284p) as an IO processor that handles serial keyboard, video, filesystem (SD card and on-board RAM and EEPROM) and it's gone from barely working on breadboard to stripboard to a PCB. I don't want to dabble with FPGAs, CPLDs (for now), but since a lot of the stuff I worked on back in the 80/90's used PALs, I've used a GAL on my Ruby board and I'm holding out to through-hole as long as I can...

And going back to my BASIC interpreter, I probably know more now about the BBC Basic 'envelope' command that I did back in the day as I made it emulate the BBC Sound - and curse that BBC, because although I tend to cite the Apple II as my "heritage", my Ruby is, more by accident than design, quite BBC compatible from a "Language ROM" point of view in that it will (should) run most Beeb ROMs that use the standard Acorn MOS interface. This includes a filing system - when I finish it.

However it does run Applesoft, and my low-level "monitor" is a bit wozmon like, so not completely alien to the old Apple II and the filing system isn't a million miles from Apple ProDOS. On my desk right now is the original Apple II Red Book, as well as a copy of the Advanced User Guide for the BBC Micro....

One idea I did have some time ago was to "re-imagine" old systems with a modern approach - I started a couple of years ago with the PDP-8, although a couple of PiDP8's later and a real PDP-8 later and I doubt I could really do anything that looked and felt like something familiar today (that was sufficiently difference from OS8 to make a difference) - there are limits. I used a PDP11 in the past and have a PiDP11, but could I improve on Unix? I don't think so, so will give that a miss...

...and then there is the 6502 - there was never (to my knowledge) a CP/M type of operating system for it (not in the 80's, anyway - I do know about the DOS65 project though) so I thought I might do something along those lines, however - that old Acorn MOS (Machine Operation System) keeps on lurking there, gloating and smirking at me to do more with it... And one of these days I might post about it on the stardot forums, but I fear they may burn me at the stake as some sort of witchcraft wielding heretic!!!

The non-UK people may be wondering what all the BBC thing is about by now - it's sad that it never really made it over the waters in a big way, but ah well. Lurking underneath the machine that went durrr Beep and landed you in a very fast and modern (for 1982) BASIC when you turned it on was actually a very clever operating system - not intended to be command-line driven, although there was a CLI interface, (the "star" commands) but to be used as a super BIOS with a set of well-defined entry points and vectors, and if you used it correctly, your code would run transparently in the BBC Micro or over the "Tube" in another, faster, 6502 plugged into it. And that's just the tip of the MOS iceberg. Graphics, sound, printers, disks, tapes, network all did their thing, all controlled by the MOS which allowed for multiple "Language ROMs" (e.g. Basic, BCPL, Pascal, Word processor, Editors, etc. ) and multiple filing system ROMs (disk, network, etc) and many other utilities.

My plans for my little Ruby board are to tidy up the IO facilities - the next revision will use a Raspberry Pi for the graphics, but I'm going to keep the ATmega on there for the bootstrap and filing system interface as it's quite handy - also without that doing the video I have a couple of spare pins for I2C - or something. Also going to stick an '816 on Mk 2 too. Hopefully nothing will notice, but it then opens up all the 16-bit stuff and more RAM. I'm also going to use the ATmega as a floating point co-pro too. Not working by bus snooping, but simple poking values into the shared memory page with a command and telling the ATmega to do it, then read the results back. Some might be quicker on the 6502 (simple add, subtract) but that's a benchmark for another day...



From front to back it's ATmega1284P, 64K RAM (2 x 32Kx8 piggybacked), WDC65C02, WDC65C22, Blinkenlights, with the vertical chip being a Lattice GAL22V10. The SD card is 8GB, but the filing system can only use 32MB devices, (16-bit block pointers of 512 bytes) however it's using a standard MBR partition table, so 4 'drives' of 32MB each. That's enough for now. The 2 small LEDs at the front are connected to the 2 x 32K bank select lines into the RAM - the yellow wire is the one going to the top bank (not intentionally unplugged here, but I'd moved it and it popped out) The blue one means the 6502 has the shared memory. These were really for early on debugging and I carried them over to the PCB as I had spare outputs on the GAL. the ICSP connector to the ATmega is under the SD-card adapter (they both use SPI)

Cheers,

-Gordon

For me, I'm a more-or-less a complete n00b when it comes to designing hardware of any kind. I've been in the hobby for 15+ years with a good 5-6 year hiatus.

I will be celebrating my 14th birthday here this August. Much of that time, unfortunately, I was a lurker. I never felt I had anything to contribute.

But it was my constant visits here, learning more and more about the 6502 and hardware in general that finally allowed me to be "good enough" to design and produce my first SBC that...wait for it....actually works!

I could not have done it without this forum. The 6502 primer has been my go-to for a long time. Every time I try to do something complicated, I go back to the primer and realize it's not about complication. This primer (more specifically, the "circuit potpourri" section) is what led me to call my first SBC the Potpourri6502.

I'm probably an odd-ball around here. You won't find another person that love all things 8-bit like myself (yes, I do enjoy a good Z80 computer from time to time). But the 6502 has always been my first love. Even though the TMS9900 was my first CPU...I was too young at the time to know it.

But why am I an odd-ball? Because I want to build computers from the mid to late 1970's. And, if I'm good enough, build computers that would have competed with the VIC-20. I enjoy the things most people loath (like cassette tapes and punch cards).

However, I want to take it beyond just building old-school computers. I want to professionally typeset the manuals. I want my vintage computers to be professional. Warranty cards, spiral bound manuals, getting started guides and brochures with all of the peripherals you can buy like serial cards, audio cards, etc. I want to create a fictitious two-page magazine ad selling my old-school computers...complete with the "business man" pointing at some cheesy bar graph on paper while saying my computer allowed his business to grow. LOL! (yes, I'm serious).

So that's why I'm really the odd-ball here. I was born 20 years too late. If I had been 18 in 1973, I would have made all of that stuff for real. Or died trying.

I wished I had the time and technical skills to pull all that off these days but real life steps in quite a bit.

On a different note, I do hope to contribute more to the forum over the years. As I learn more, I hope I can help a newbie or two along the way. I also hope that some of my cheesy old-school computers will bring at least some entertainment to someone one day.

I'm sorry if my rambling went OT on here. But it felt like a reflection subject on who we are and what we've done.

(Thanks for sharing your stories!)

I have no hardware. (Well, not quite true, I have a Raspberry Pi I bought, probably, a year ago that is still in its box.)

All of my work has been in software.

Couple of years ago I was able to muster up enough free time and enthusiasm to create a 6502 simulator and an accompanying assembler with the goal of getting the FigForth assembly listing to work. That was pretty good fun, and I managed to pull that off. But then things went back on the shelf.

Since then I've been ruminating on what to do next, what do I want next, as my whimsies and such drift hither and yon, but nothing of note was really accomplished.

Currently I'm attacking my simulator again and I'm making it a 65816 simulator. Part of this is relearning how it originally worked, I've got the instructions all captured, but not the logic for the new addressing modes. My memory model needs to be readdressed at a minimum. The '816 has a bunch of subtle nuances, so that'll be some detail work (which I'm terrible at, but c'est la vie).

One clever bit that I'm going to add to it is I'm going to capture the processor status each time I access memory, in order to make the disassembler more accurate. So, if you execute code and then view it's disassembly, then it'll be correct (regarding the affect of M and X flags). No REP/SEP tracking and guessing.

I may look in to see if I can tap in to the symbol table from CA65 somehow, and let the simulator be aware of it so that if you dump a stack trace, for example, it'll have a bit of a symbolic functionality to it, add symbolic functionality to the disassembler, etc. Either that or I augment my assembler to do it.

The drive here is to facilitate the development of what I'm just calling "SuperPI/O", the RPi based I/O processor I've talked about before elsewhere. For my needs, I think this is the best way forward.

I did manage to work a little with EasyEDA, and get a schematic in, a board laid out. Something I have not been able to accomplish with any of the other tools, so that means there's actually a light at the end of the tunnel of actually, maybe, doing something in hardware someday.

My current "fantasy" system is the '265 board with 1-4M of RAM (not that I need 4M of RAM, but it seems the incremental cost is low enough to "why not"), connected to the SuperPI/O processor with appropriate magic happening.

So, those are the irons in my fire at the moment.