On Thursday, February 19, 2004, at 12:04 PM, Christopher McNabb wrote: Sure, we could put 2 words of LED's and 3 words of switches and the rom monitor could look at those as well :^) Addr_____________________________ o o o o o o o o o o o o o o o o data___________ VVVVVVVV VVV^^VVV ^VVVVVVV dddddddd aaaaaaaa 12345678 sw1 run/stop sw2 examine sw3 deposit sw4-8 Sense

Surely, NOBODY needs more than 640K!

On Thu, Feb 19, 2004 at 01:32:48PM -0800, Patrick Rigney wrote: I own two as well, but I haven't built them... I have 1802 and 6120 projects further up on the priority list. It does look fun to build, though, and the 6502 is one of my favorite uPs. -ethan -- Ethan Dicks, A-130-S Current South Pole Weather at 20-Feb-2004 09:20 Z South Pole Station PSC 468 Box 400 Temp -46.2 F (-43.5 C) Windchill -95 F (-70.59 C) APO AP 96598 Wind 13.3 kts Grid 066 Barometer 691.7 mb (10187. ft) Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html

A C64 might not be as optimal, though, because it has a 6510, not a 6502 (unless you really do want the on-chip I/O port). For common-as-lint Commodores, if you really must, gutting a *sniffle* VIC-20 may be a better choice. (Sellam, I haven't forgotten about that disk, honest.) -- ---------------------------------- personal: http://www.armory.com/~spectre/ -- Cameron Kaiser, Floodgap Systems Ltd * So. Calif., USA * ckaiser(a)floodgap.com -- There are few problems that the liberal usage of high explosives can't cure.

In message <Pine.LNX.4.33.0402191428510.22767-100000(a)siconic.com> Vintage Computer Festival <vcf(a)siconic.com> wrote: Not in my opinion :) If I had two broken VIC20s - one with a fried VIC, CPU, etc. and the other with a dead keyboard, I'd move the working keyboard into the machine with the dead keyboard. As for the utterly fried one? Find out which parts are toast, then gut the board and keep the working parts. Of course, if there's a white ceramic 6502 with gold coverplate, I'd keep that even if it was dead. Later. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI ... This is your head..THiS iS yoUR HeAD On WindOwS.

At 10:14 PM 2/19/2004 +0000, you wrote: Z80s (and others) along with their support ICs are readily available from places like: http://www.jameco.com --tom

And 1802s and 6800s as well... --Patrick

On Thu, Feb 19, 2004 at 10:14:14PM +0000, Jules Richardson wrote: I guess my house has more lint than dirt. :-) I aquired a double-fistful of 6502s from a pile of stat-mux boards I carted off from a local fellow list-member (and have had good luck extracting a few 74HC parts for my SBC6120s). There are even a few items like burglar alarms that you can find an 1802 in occasionally (if they are from the right era). So... for Z-80, 6502 and the odd 1802... check those clunker boxes... you might find something interesting in one of them -ethan -- Ethan Dicks, A-130-S Current South Pole Weather at 20-Feb-2004 09:20 Z South Pole Station PSC 468 Box 400 Temp -46.2 F (-43.5 C) Windchill -95 F (-70.59 C) APO AP 96598 Wind 13.3 kts Grid 066 Barometer 691.7 mb (10187. ft) Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html

Actually, no ... it's the PLA, most of the time. The SID won't cause a non-working machine if it's blown (I've blown SIDs many times on SX-64s due to a well-known board fault on the video port, and the machine still works, just without sound, of course). If I wear a blue shirt, I get a lot of blue lint ;) They're not too hard to find, in any case. Don't buy them from eBay, find a private collector. For the two I own, I paid a grand total of $30 (really). -- ---------------------------------- personal: http://www.armory.com/~spectre/ -- Cameron Kaiser, Floodgap Systems Ltd * So. Calif., USA * ckaiser(a)floodgap.com -- Tell the truth, and run. -- Yugoslav proverb -------------------------------

On Thursday, February 19, 2004, at 03:30 PM, Cameron Kaiser wrote: i'd give you $30 for one of them... if I had a job :^(

Ron Hudson wrote: Uhm, I have one but you can't have it. You can look at pictures of it though. http://cmcnabb.cc.vt.edu/cube_museum

Vintage Computer Festival wrote: That's how I got the 6551 chips -- from old Apple ][ serial cards, which I found at the National Vintage Communications Fair: http://www.nvcf.co.uk -- John Honniball coredump(a)gifford.co.uk

On Thursday, February 19, 2004, at 02:22 PM, J.C. Wren wrote: My main use for the machine is to get back to a machine where I can program in machine code, right down on the "iron" I expect to eventually write a focal/basic/somthing interpreter for it. Actually, as several people pointed out, I meant 64K not 640K.. :^) Probably Through hole, wire wrap - as that would allow the greatest number of us to play. Main goals - simple + cheap. PIC's are special purpose aren't they?

Has anyone considered the Gizmo? Has all of the features that have been mentioned here. Available as a kit or pre-built. As a bonus it is software compatible with a PDP-8 (you can actually run Focal-69 on it...) I have one here, that I use quite a bit. Not true classic iron, but while I wait for a real PDP-8, it fits a nice void.... Of course if anyone has a true '8 that they would like to trade ;)

If I were going for audience appeal, and you don't plan to be booting CP/M or some other free readily available O/S from the get-go, I'd aim for something that was was well supported. For me, SIMH was a powerful tool in getting the Z80 SBC up. I'd compile the BIOS under the SIMH Z80 emulator running CP/M, upload it to the Linux box, and download it to the ROM emulator. Turn around time was very quick. Problem is, Z80's aren't real interesting. There's lots of software, but they're kinda old hat. Homebrew 6502 systems seem a lot less common, making thier interest level, for me, higher. 1802's even more so. I would favor a CPU that has a static core. Being able to toy with the clock is helpful, especially in the early stages of bringup. While concievable that you could write a disk-based OS on a 8031, the architecture doesn't lend itself well to that. I'd pick something that has a real stack, with a real von-Nuemann architecture. Yes, you can play games with an 8031 and overlap the code and data space by AND'ing /PSEN and /RD, but the instruction set still lacks a real stack, and you're limited to 1.5 16 bit registers (I'm counting the MOVX @P2 mode). Obviously, building something with an external 32 bit bus is going to be more work than a 8 bit or 16 bit bus. 16-bit address and 8 or 16 bit data would be middle of the road. Are you going to stick to 5V logic, or 3.3V? With 3.3V logic, you've got a lot more available choices, these days. If you wanted to play with an ARM core, as far as I know, there are no 5V ARM cores. Or if there are, they're not very common. One neat part is the Philips LPC2106. 128K bytes FLASH, 64K bytes RAM, all on chip. ARM core, timers, 2 serial ports, GNU tools readily available. But it's SMT only. And 3.3V I/O with a 1.8V CPU core. Something like a 6809 would be fun (I like those). When you're done, you could boot OS/9 or Flex/09. If you want to write on the bare metal, it's got a nicer instruction set than the Z80, but lacks registers. You make up for that with more addressing modes, and better relative branches. With a 6809E, the bus interface doesn't get much easier. The original 6809 was a lot more trouble to work with because of the clock requirements. 1802s are fun, too. The have a really neat instruction set that's way ahead of it's time, in some respects. It lacks a real stack, however, so you have to use 7 instructions are so to build a real stack in external memory. There's a fair amount of software, but CPUs are going for ~$10/ea, and the commonly availabel CDP1802ACE is only a 3.2Mhz part. If you want the 5Mhz part, you need a CDP1802BCE, and those are going for a lot more money. The max specs say you can run a 1802 at 6.4Mhz with 10V, but the > 5V parts are less common. You also have to use all CMOS glue logic. Single stepping and using switches to enter/edit memory is trivial. The CPU design supports that pretty much instrinsically, with little extra logic needed. Then there's the venerable 6800. Lots of software, lots of emulators, and OSs are available. Common, easy to find. Sorta like the Z80, though. It's common. You could build a 68000 system. Those are pretty easy to find, have good support, etc. 68K homebrew systems seems to be far less common than Z80s and 6800s. I don't know what support chips you'd need/want to make it play. I've used 68K systems, but never built my own. Slightly on the sluggish side, if you're looking for speed. I don't think the 68Ks started getting fast until the 68030 or so. The 68020 was better, but still no speed demon, IIRC. The NSC32000 would be an uncommon homebrew system. Software may be hard to find, including emulators. I don't see a lot of 32K parts going by on eBay, so you might be hard pressed to come up with what you need one. Same for the Zilog Z8000. These are all the common 8, 16 and 32 bit systems I can recall. At some point, trying to homebrew something like an 80286 gets to be too much trouble. And little reward, in my book. I feel good everytime I throw away anything x86 that's less than an Athlon 1Ghz. And even those are getting ready to get moved to the "why bother?" list. There were some oddities, like the 6502 Forth chip, and several other Forth processors. I don't think I'd want anything with BASIC build in, like the 8031AH-BASIC (you said you wanted bare metal, anyway). Any basic families I missed here, not counting variants like 6510s, CDP1805s, etc? --jc Ron Hudson wrote:

Use a DIN 41612 'indirect edge connector' (as used on Nubus boards, etc). They have the advantage that you don't need to gold-plate the PCB (AFAIK impossible to do at home, the chemicals are nasty...), and thay they're darn reliable. -tony