Hero

The Museum has allowed us to hack on an old Heathkit Hero, more specificly, the Hero 1, AKA ET-18. From the testing procedures, everything appears to work except moving the motors -- which is currently diagnosed as bad batteries. I've taken photos of the schematics, though I have yet to post them online (they still have an active copyright holder -- Heathkit sold the copyright to the manuals). From that, I think that my original plan of driving the robot from the experiment board won't work -- the experiment board doesn't have direct access to the other perpherials, so we'd have to write driver code on the main CPU to implement a protocol over the experiment board, instead of driving things directly. However, a number of debug headers seem to exist on the CPU board, which may be powerful enough to essentially replace the CPU without modifying the hardware.

While writing the below, I found [], which may describe the best route forward.

Headers:

P406, on CPU board -- buffered address box, low bits:

1. low when VMA high and address bits a15:a13 = 2 (a14 high) -- VMA=valid memory address -- 0x4000-0x5FFF 2. low when VMA high and address bits a15:a13 = 3 (a13, a14 high) -- 0x6000-0x7FFF 3. BA7 4. BA6 5. BA5 6. BA4 7. BA3 8. BA2 9. BA1 10. BA0

P408, on CPU board -- buffered address box, high bits:

1. low when VMA high and address bits a15:a13 = 4 (a15 high) - 0x8000-0x9FFF 2. low when VMA high and address bits a15:a13 = 5 (a15 and a13 high) - 0xA000-BFFF 3. BA15 4. BA14 5. BA13 6. BA12 7. BA11 8. BA10 9. BA9 10. BA8

P407, on CPU board -- unbuffered data bus (note: numbers not marked on schematic, so are guess): 1. R/W line, notted and buffered? -- after not, high=write, low=read 2. !RESET 3. D7 4. D6 5. D5 6. D4 7. D3 9. D2 10. D1