That's why you need rock-solid documentation! I mean the kit.

Could not agree more. Bender robot form Futurama has a 6502 brain!

I like the Micro KIM and Vince Briel's SBCs. However I would do something from the scratch or the SBC-2 or the UK101 (with permission, needless to say). There's nothing against the KIM it's just I don't know if the creator would want to share his already successful design.

Instead of project I'd rather say daydreaming:)

The one suggestion I have if you use the SBC-2 design is to use a different USART. The 6551 is getting harder to find and are usually older parts. An Exar XR68C92 is a dual-USART with 6502-compatible interface. I used it on my SBC-4. It also operated at the higher standard baud rates.

Daryl

_________________
Please visit my website -> https://sbc.rictor.org/

Frankly, depending on the goal of the curriculum, I think #3 is less complex than #1.

If one of the components is a working monitor ROM, wiring up a UART/VIA seems to me to be a lot simpler than wiring up a keypad/switch and light display. There's a lot of discrete logic involved in doing that, which overcomplicates the design.

It would be a great 2nd stage project, but there's something to be said of having a system that's little more than a CPU chip, an EEPROM chip, a RAM chip, a VIA, and a clock. It's effectively an operating block diagram.

But this brings up another point.

I think this could be an interesting 2 semester course, with the first semester focused on digital logic theory, assembly, tools, etc. while the second would be actual design and creation of the computer with some control experiments in the late part of it. I don't think you could safely just start with a computer build and no digital electronics background.

It would also be nice if the design could be accomplished on a breadboard. I think they're more accessible and useable than wire wrap, and encourage experimentation. If it's a speed issue where it's simply not safe to run at 1MHz (it's too unreliable), then clock it down. I don't know much about that, though. Just seems when the cost of change is low, change can happen more often. Not doing weather modeling here, just seeing lights blink on and off is exciting.

It would actually be interesting to build it on a breadboard, boost the clock speed, watch it fail, show on test equipment (scopes, whatever) why its failing, then have a WW version going faster until it fails, and finally a PCB version. Just to help show limitations of the different techniques. No reason for the students to do this, but it would be an interesting presentation (to me at least).

Thanks Daryl, will do!

I know some some might find using a USB port blasphemy and I understand the sentiments. On the other hand, many computers these days don't have serial port. My computer for instance does not have any and I would need an Arduino or an other UC to interface serial devices with the host machine. Also, USB would allow the users to write Android/Symbian/iOS apps to load and save programs, have a virtual screen, see the memory contents, etc. I love the TinyElf for instance, a COSMAC Elf emulation for Mac. Not only it features a 'fake' TV screen but it allows you to see what's in the registers (accumulator, etc.), RAM etc.

http://www.tinyelf.com/

Also, ideally the potential customers could buy keyboard and LCD expansion or buy a uber-kit that comes with everything or chose the economy-version with just serial/USB.

I would love a course like that!

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

_________________
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?

For the usb i think that is best to leave it to the usb to serial adapter. On my system i have a adapter pcb that i got from ebay, and it is connected to the mc6850, and since that the mc6850 ca go up to 1 megabit, it can be very fast. Also drivers are trivial, for XP i had to install the cp2102 drivers, and it worked with no issues, and i think that newer os have built in drivers for the cp2102.

BDD and all,

While I found the Exar 68C92's performance, bus compatibility, and configuration very easy and reliable, I concede that it is harder to come by and cost a little more. That said, the 26C92's from NXP are less expensive and more readily available so are a better choice for the hobbyist and/or kit manufacturer.

Daryl

_________________
Please visit my website -> https://sbc.rictor.org/