Re: It's "Deja vu All over Again" -- 68000/68010 or 68020 Boards, Anyone?

Well just a few comments. Preliminary work with the V3 IDE prototype appears that it will work with the current 68K board. I would wait until we get the final board (due in a few weeks) to make sure it works. I would like to see a few changes to the 68K board as well - first make it better support being a bus master and to run reliably at 8MHz. I think using some GALs would be highly desirable to reduce the density of the board as well. Along with reducing the complexity use less SRAM on the board - there is no practical need to have that kind of memory at that address - use something smaller in smaller pdip format - it is a good area for stack, disk buffers, etc so it does not have to be so large. Another thing is move to a PLCC version of the 68K as this is less space - the current 64pin dip package tends to work itself out of its socket over time which causes extra debug at times. I think a 68020 is not practical because of buss access requirements.

Dave

On Sunday, May 24, 2015 at 4:28:38 PM UTC-5, Howard Feindel wrote:

Well, folks, it’s been almost a year since the postings in June 2014 (thread started by Ed Snider in May) in which John solicited comments on a 68K CPU board with minor revisions from the V3 board, a reworked board, or a 68020 board. The last posting was by Josh Bensadon on 04 June.

Then, in January of this year, Rick Bromagen started another thread, which petered out in February after John’s final posting.

The 68K CPU board was my main reason for getting involved with this group in June of last year. Unfortunately, since then, I haven’t seen anything definite regarding another production run for this board.

So I contacted John this morning regarding the current status of the board, and here are his comments:

Unfortunately the 68K board has kind of fallen off the wagon. There were some timing issues above 6-8MHz that really need a deep study of the signals. I’m so rusty on the 68K signals/CPU it would need an extensive time commitment to debug.

Somebody else had problems trying to get the current board working with the V2 IDE board. I think it was Yoda, (traveling so I cannot check). This was one of the reasons for doing the V3 IDE board. On a V3 prototype he seem to feel it now worked.

My suggestion would be to put up a post on the Google’s Group and see what the interest and consensus going forward would be.

I certainly can do another board if there are just small changes. For example 4 boards by PCBCart run about $170 + FedEx.



John

Personally, I want two 68000/68010 boards, either V3 (with the updates) or a new GAL-based version, and preferably with 68K-master/Z80-slave capability. And I'd like very much to be able to run them at higher speeds than 6-8MHz. I'm more than willing to wait a while to give John time to wave his trusty magic wand and give us a stable 68K CPU board that will run above 6-8MHz and work well with other boards. Going forward, I’d also be interested in a 68020 board, but that will, of course, require lots of work.

I’d also be interested in finding out from someone (Yoda/Dave, perhaps?) if the new production V3 Dual IDE/CF board definitely alleviates any of the issues with the V3 68K board. I’m not sure whether or not there are problems with the 68K and the Propeller I/O board. Comments, anyone?

In line with John’s suggestion that we see what interest currently exists for the 68K CPU boards, let’s see where everyone currently stands. Here’s an update to the latest list that Ed Snider posted last year (I added Jack, Josh, Rick, and myself to the original list):

1.   Fabio Battaglia      -        3
2.   Paul Birkel            -        1

3.   Todd Goodman     -        3

4.   Brian Marstella      -        1

5.   Jerry Brumble       -        2

6.   Gary Kaufman       -        2

7.   Andrew Bingham   -        1

8.   Matt Turner           -        2

9.   Yoda                     -        1

10. Andrew Kwan        -        1

11. Ian May                -        2

12. Jack Rubin            -        1

13. Josh Bensadon      -        1
14. Rick Bromagen      -        2

15. Howard Feindel     -        2

Total:      25

(I assume that everyone would prefer an updated V3 board rather than just another run of the current V3 board. If not, sound off, please.)

If you’re not listed but are interested, or if your interest or quantity have changed, please post and so state.

Thanks,

HWF