Hello!

I would like to find some 6502 chips (or even just one) to experiment with for my first real CPU chip experimentation.

Seems like any big companies have minimum order limits, but I'm not sure where else to find them (sort of ripping the 6502 out of my old useless Vic 20, depending one how it's mounted of course .

Any ideas?

Thanks!

Arlo

Though I've recentlyheard that Jameco is discontinuing their 6502's, the chips are still available. You do have to be careful about the version, because some, especially the several CMOS versions (65C02, 'SC02, etc) are not necesarily compatible with the older NMOS versions. The VIC, IIRC, uses a 6510, which is completely different from the old version as its pinout is different.

They're out there, though. I run into it in control applications pretty regularly.

Uli

Looks like Mouser Electronics doesn't carry any of the 65xx series anymore either. Whats going on? This used to be a really popular hobbyist CPU.

- Paul Zaleski

Well, it was, that's WAS, a really popular CPU for hobbyists, but hobbyists won't keep it on the market. What keeps such items in the market is the dozens of companies using 100k per year.

AFAIK, there are two vendors claiming to sell the 6502 in one or another incarnation, but since one is the 65SC02 from WDC and the other is basically the Rockwell model, which is also a 65C02, albeit with a BUNCH of handy instructions, but incompatible with the old NMOS parts, they're not so popular.

If you have access to the necessary resources, I'd recommend you "roll-your-own" in an FPGA or a CPLD and include whatever additional hardware, instructions, and features you deem justified, and go with that. I've been working, on and off, on a 650x core for use in a field programmable device. I'm not anxious to modify the model too much, since I'd like to avoid rewriting the already available macro-cross-assembler <AD2500> I've got, but I do want to include a few I/O instructions and perhaps some block-transfer instructions including I/O <=>memory types. We'll see. My main goal is speed, and as the technology evolves, the speeds are going up.

Uli

>Whats going on? This used to be a really popular hobbyist CPU.

There's a lot of competition out there.

For "hobby" users, I suspect that the "serial-oriented" chips
such as the PICs and Scenix are very attractive. I just recently
started working with the PIC 16F84 chip -- it's an 18-pin device

(most pins are I/O), it has internal flash for storing code, and you
update the code by downloading thru a serial port. You can build
a gadget that "does something" with a minimum of wires and other
devices. The fast version has an instruction execution time of 200 ns.
For making relatively simple devices, it's hard to beat.

Pete

If you're one who likes the flash ability of the 16c8x and other PIC's, a good hard look at the SCENIX SX is certainly warranted. They're more or less similar (not identical) to the 16C5x series of PIC's but they operate at 1x the input clock rate and that can be as much as 100 MHz! What I like about these is that you can program them to behave as a bus-interfaced peripheral device to, say, a 6502, and allow them to respond to an interrupt as chip select, then read the port bits and make a decision as to what to do, then do it, all within the 300 ns window most peripheral chips require for bus interfacing. That means that you can build your own peripheral device with special characteristics you need, or you can emulate one you can't get any longer. Moreover, you can build a timer, for example, that has a 32-bit counter pair instead of an 8-bit pair. Let your imagination be your guide! Inspiration can be had by looking at the now-irrelevant spec's for the i8742, which was a customizable peripheral interface.

enjoy!

Uli

I just checked the Aug-Oct '00 Jameco catalog, and they do still have the 65 family. Just to make sure, I also checked their website. Same thing. Then I checked California Micro Devices' website, and they're still making it, although I've heard Rockwell was discontinuing it.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Dear sir, I am a new guy in the area of chip design. However, I am very interested to touch on chip design. It seems to me you have a lot of fun playing the 65xx core. Can you give me any idea where to get ( to buy) the source code of 65xx? I would like to build my own chip of 65xx with timer and interrupt. Thanks for your help.

Best regards, jeff

You can purchase a core version from the WDC people who don't seem to want to sell the packaged devices, preferring instead that you buy their core license.

There is a free (public-domain/open source) 650x core listed as free-6502. A pointer to that can be found at www.6502.org.

Making your own device via FPGA/CPLD tools and a published IP core is probably a good place to start. However, it's not a bad idea to rework the innards of the core to suit your own idea of how the thing should work. In order to understand the workings of the core, particualarly with respect to its use of the ALU, I recommend writing a detailed simulator of the original part (MOS-Technology) pursuant to its cycle-by-cycle characterization of the device's external signals throughout each instruction cycle type. This is best done in a high level language like C++. Then, since there are a few VHDL compilers out there that take C++ input, you will have minimal trouble getting from the knowledge and understanding of the core's internal operations to a physical implementation.

My interpretation of the core operation involves use of the ALU twice per clock cycle: once to perform the normally thought-of ALU operations on data operands, and once to operate on the PC, SP, index registers, and status. I'm also leaning toward a 4-bit ALU used twice, though that doesn't seem to be yielding the savings in hardware resources that I originally believed it would. I'm attempting to implement this in a relatively large CPLD rather than an FPGA.

I'd encourage you to make a fairly throrough investigation of the device types offered by XILINX, ALTERA, and ATMEL, though there are several others equally worthy of your attention. I find the CYPRESS CPLD's very tempting, but their software is not free as that from ALTERA, ATMEL, and CYPRESS is. Lattice also has free software that deserves a look. I'd recommend you start with the XILINX devices, in that case with the focus on their 9500 CPLD's and their SPARTAN series of FPGA's. (Each of those is found at www.<company_name>.com, with the exception that Lattice is latticesemi.com.)

For now, the XILINX stuff has to be run via the www, i.e. you install the interface software on your computer and then run the software over the web. That ensures you use only the latest and "greatest" of their software. It's really slick if you have a cable modem or DSL connection, or faster, but it's tolerable if your analog connection is at 40 kb or better.

The most comfortable way to get the Lattice, ALTERA, and ATMEL stuff is to email them at the literature request address on their website and have the software sent to you on CD. Be sure to get the device data CD from them as well, since you'll need to know the characteristics and capabilities of each device. Once you've learned to use the tools, you'll find that you can make use of published functions such as UARTS, etc, available on their sites, along with other hand features like their devices' in-situ-programming hardware and software. These devices are, for the most part reprogrammable and many are programmable from a JTAG port made from your printer port and a cable you have to build yourself. They often require some simple external circuitry to buffer the port, but that's published on their site as well.

I bought the Cypress device development kit which includes their VHDL compiler along with a programming cable and an evaluation board with one of their devices on board. I had to build a manual crosspoint switch to allow me to reconfigure the pinout without building a separate cable for each vendor, but that's not a big problem either.

be sure you read all about their programming algorithms and I/O voltages. It's easy to get confused between device families that have different I/O voltage levels.

regards,

Uli

Where can I find more information about learning about the FPGA/CPLD tools? I have been to the latticesemi but I can't find anyplace to start from.

Thanks,
Bryan

Well, from Lattice, you get the DesignDirect software, from Altera, you get the (also free) E+Max software, and from Xilinx you get the Webpack. Atmel also offers a Synario version. That should cover most of the stuff. Pay particular attention to the download cable and "in-situ-programming" (ISP) hardware, since that's what makes all this stuff accessible.

While you're at it, you might download the 5 diskettes for PALASM and another 5 or 6 for MACHXL, both from LATTICE. Those are older tool with lots of public domain sources. ABEL-HDL is available from one or more of the above vendors, so that's worth a look. Also, I believe that ATMEL has an OEM version of WinCUPL, which is another PLD programming language. Translators and other migration tools from one HDL to another are becoming more available, too. If you're interested in VHDL, and/or Verilog, there are Schematic<=>HDL translators surfacing everywhere. Though they won't do your work for you, they can surely clear up confusion about how to specify a given circuit.

Uli

It looks like Jameco has finally stopped selling the 65xx series of chips. Anyone know of a source that's still selling?

Thanks.

I just checked Jameco's website, and they still have the 6502, 65c02, and 6522, but not 65c22. I did not enter any other family parts to check. Debco Electronics, at www.debco.com also has them. I think if you search the web, you'll find plenty of places that still have them. Some companies like Jameco don't put everything in their catalog; so just because you don't see it there anymore doesn't mean they don't have it.

California Micro Devices is still making the 65C02, 21, 22, and 51, but the fastest 65c02's and 65c22's come from Western Design Center, and they plan to continue them indefinitely. They don't sell many parts, as their main business is licensing the technology to other companies who embed it in their own custom ICs. I got word recently that one licensee is running a 65c02-based custom core at 200MHz.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Anyone know of a source for the R6511Q CPU chip? I am in need
of several of them. If you have a spare or two lying around
please let me know.

Regards,

Robert