Wouldn't hurt to see a picture. I saw info on the address translation for os9.
------- With the daughterboard switch enabled, the OS/9 mapping is: 6809 6502 0xxx 1xxx ... ... Axxx Bxxx Bxxx Dxxx L/C Cxxx Exxx L/C Dxxx Fxxx L/C Exxx Cxxx I/O space Fxxx 0xxx ZP+stack+text -----------What this doesn't tell is how the A15 inversion fits into this picture. My guess would be that the soft switch still inverts A15 but is not used with OS9.
Clearly the address translation should be done with a GAL in the 21 century. Originally I thought that 74LS259 would be impossible to find and a CPLD should replace it along with some glue logic. Well, apparently the same Jameco (which happens to be a couple of miles from where I live) still stocks them! So the lazy approach will be to just duplicate the original design plus the address translation minus the never used EPROM.
On 6/2/2012 6:20 AM, Steven Hirsch wrote:
On 06/01/2012 05:09 PM, Alex Freed wrote:If 10 people wanted a clone of the Stellation Mill card, I could make the boards using real 6809E CPUs available from Jameco.Alex, I would be interested in one of these. It would also be a good idea to clone the MMU piggyback that permitted the card to run OS-9. I have some clear front and back photos of the piggyback that would make reverse-engineering a snap. Let me know if you want them. Steve