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

[Skate323k137]

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:

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):

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

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

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.

 

[jajan547]

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

 

[Skate323k137]

I've uploaded the Gerber / ROM / project files and a basic readme to Github, for future sake and so that folks do not need to register to download them.

GitHub - Alex-Kw/Brain-Board-II: Updated "Brain Board" for Apple II, originally designed by Mike Willegal

Updated "Brain Board" for Apple II, originally designed by Mike Willegal - GitHub - Alex-Kw/Brain-Board-II: Updated "Brain Board" for Apple II, originally designed by Mike Willegal

github.com

Today I tested "Worple," A cleverly coded wordle-like Apple 1 game that fits in 4K of memory. It works fine on the Brain Board (And replica 1+)

GitHub - JeffJetton/apple1-worple: Wordle clone for the Apple 1

Wordle clone for the Apple 1. Contribute to JeffJetton/apple1-worple development by creating an account on GitHub.

github.com

 

[Skate323k137]

One update today, as I uploaded a new ROM which takes advantage of the extra space differently. The original stacked ROM had Wozaniam in both low banks. I rearranged it so that one low bank contains integer basic and the other contains wozaniam. The normal mode of the brain board omits the top bank for the system ROMs. With this rearranging of the ROM space, the card can be used as an Integer BASIC card, or Wozaniam (apple 1) card, both using the rear main toggle to enable those modes. Selection of which is based on dip2, while leaving the system ROMs intact with the default DIP settings. Previously, to have Applesoft and Integer with wozaniam, both Applesoft and Integer BASIC were on the card, disabling access to the on board system rom.

Updates have been published to my github:
https://github.com/Alex-Kw/Brain-Board-II/

New Rom file:
https://github.com/Alex-Kw/Brain-Board-II/blob/main/Forum Pack/QuickStart.BIN

 

[Arbee]

Cool to see Mike’s work extended!

Regarding the IIgs, cards like this or the language card that use /INH to override the ROM won’t work (the GS uses the 65816 vector pull signal to force reset and IRQs to the onboard ROM). I think one of the technical notes said trying would cause a bus fight and possibly damage components on the motherboard.

You could probably load a version of the ROM from disk on the GS and make it run that way but the card is a no-go.

 

[Skate323k137]

Cool to see Mike’s work extended!

Regarding the IIgs, cards like this or the language card that use /INH to override the ROM won’t work (the GS uses the 65816 vector pull signal to force reset and IRQs to the onboard ROM). I think one of the technical notes said trying would cause a bus fight and possibly damage components on the motherboard.

You could probably load a version of the ROM from disk on the GS and make it run that way but the card is a no-go.

Thanks

Unfortunately IIGS is out. But I'm glad for II+ and IIe I was able to make Integer BASIC and Apple-1/Wozaniam easily accessible on a single card without fully reconfiguring the DIPS and/or bypassing system ROM.

Also in the edge case of someone with a II+ with on board Integer Basic rom, the Brain Board ROM could be rearranged to place applesoft and wozaniam there.

My writeup on this update was published to the front page of AppleFritter (Thanks Tom).

The Brain Board II: Bringing Integer BASIC and Apple 1 emulation to your Apple IIe/II+ with a single card | Applefritter

www.applefritter.com