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Reviving Mike Willegal's 'Brain Board' For Apple II computers

Skate323k137

Well-known member
UPDATE:

I was able to add a pull up resistor to the PCB, which along with some other quick revisions enables manual use of DIP2 to toggle Integer or FP Applesoft Basic by toggling the highest address line of the 27C512.

The ROM Code was provided by Macnoyd from AppleFritter, who has given permission to share his concatenated ROM file.

DIP switches recommended for initial use for this are different than the normal quick start for the original Brain Board. With the toggle in Apple 1 mode (up), the machine runs the wozaniam pack as normal. With the toggle down, either FP Applesoft or Integer basic is booted by the Apple II from the Brainboard ROM.

Some photos of the updated design:

0Ekxdmo.jpg


LTRlzqb.jpg


This photo shows the new PCB next to an original one. Normal operation is the same if you follow the quick start guide from the original Brain Board manual.

DIPS:
1,3,5,8: ON
4,6,7 OFF

The updated design to take advantage of this modification uses the following configuration:

1,4,5,7 ON
3,5,6 OFF
2 - FP/INTEGER

With this configuration on the new PCB, DIP 2 (Previously of no function) now toggles Integer or FP Applesoft BASIC on the Apple II

As such, the following options are available on the new version of the PCB dependent on the toggle and DIP2,

Apple 1 mode (back toggle up):

ahAaOjU.jpg


Apple 2 with Integer Basic (Back toggle down, BASIC version dependent on DIP2):

JLW92xW.jpg


Apple 2 with Floating Point AppleSoft BASIC (Back toggle down, invert DIP2):

PIhb54x.jpg


I will likely be making some surplus PCBs and maybe even a couple of DIY Kits available. Because this is an open source design and Mike Willegal has kept everything available and public, as promised, I will do the same. Please find attached to this post:

- The 27C512 ROM image provided by and posted with permission of Macnoyd. You need to use a 227C512 on this new revision, do not use a smaller ROM.
- The Gerbers exported from the Osmond project for convenience, ready to be manufactured at PCBWAY (choose beveled edge connector option during ordering). These are the same ones used here.
- The Osmond file with my revisions (Osmond is a free PCB editing program which was used to design the original Brainboard). This is able to be modified freely, and has already been updated for proper gerber export filenames. Export to gerber and then delete AUX2's file before zipping and sending to production if you modify this design.
 

Attachments

  • CO.512.SuperBrain_Board AppleSoftInteger.BIN
    64 KB · Views: 11
  • Beta_4_gerbers.zip
    32.9 KB · Views: 10
  • BrainBoard_512_Beta_4.zip
    34.2 KB · Views: 10

jajan547

Well-known member
Happy they are working great, I really want to build my new boards but still waiting on parts. Big sad.
 
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