SPEC_O_P.EQN

PAL O equation for PAL14L4 device

eqn - 1.89 kB - 11/27/2025 at 01:01

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SPEC_O_P.LOG

PAL O log for PAL14L4 device

log - 2.51 kB - 11/27/2025 at 01:01

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SPEC_Y_P.JED

PAL Y fusemap for PAL14L4 device

jed - 816.00 bytes - 11/27/2025 at 01:01

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SPEC_Y_P.LOG

PAL Y log for PAL14L4 device

log - 2.43 kB - 11/27/2025 at 01:01

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SPEC_O_P.JED

PAL O fusemap for PAL14L4 device

jed - 699.00 bytes - 11/27/2025 at 01:01

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SPEC_Y_P.EQN

PAL Y equation for PAL14L4 device

eqn - 3.80 kB - 11/27/2025 at 01:01

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SPEC_O_K.EQN

Logic source code. Outputs match the original PAL chip.

eqn - 1.89 kB - 11/15/2025 at 06:17

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SPEC_Y_K.EQN

Logic source code. Outputs match the original PAL chip.

eqn - 3.80 kB - 11/15/2025 at 06:17

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SPEC_O_K.JED

JEDEC file for GAL16V8

jed - 878.00 bytes - 11/15/2025 at 06:17

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SPEC_Y_K.JED

JEDEC file for GAL16V8

jed - 997.00 bytes - 11/15/2025 at 06:17

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spec_bitmap_comparisons.ods

Spreadsheet used to compare the pin fuses. Seems good.

spreadsheet - 20.68 kB - 11/03/2025 at 02:56

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Speculator_circuit_1st_sketch.pdf

First sketch, not neat, component numbers and values need checking, but it shows the architecture fairly well.

Adobe Portable Document Format - 151.40 kB - 10/27/2025 at 22:55

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Speculator Bill Of Materiel.ods

Part numbering follows Memotech circuit, extra part numbers then assigned by me.

spreadsheet - 14.19 kB - 09/25/2025 at 21:24

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Einstein Speculator analysis.ods

Every IC pin and where it goes to.
I still need to work out the discrete tape and diode-OR logic, but it should help anyone trying to make a circuit diagram a lot.

spreadsheet - 18.93 kB - 09/25/2025 at 21:24

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Speculator circuit part 1.png

Connection of RAM, PALs and Einstein connector.

Portable Network Graphics (PNG) - 57.19 kB - 09/17/2025 at 22:05

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SPEC_O_K.EQN.txt

Equations for the PAL marked with a Y, edited to have actual pin names. This is IC4.

plain - 809.00 bytes - 09/22/2025 at 22:55

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SPEC_Y_K.EQN.txt

Equations for the PAL marked with a Y, edited to have actual pin names. This is IC3.

plain - 1.31 kB - 09/22/2025 at 22:55

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SPEC_Y.EQN

Output of PAL2EQN for the PAL marked with a Y.

eqn - 639.00 bytes - 09/17/2025 at 21:53

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SPEC_O.EQN

Output of PAL2EQN for the PAL marked with an O.

eqn - 535.00 bytes - 09/17/2025 at 21:53

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SPEC_Y.jed

JEDEC fusemap for the PAL marked with a Y.

jed - 702.00 bytes - 09/17/2025 at 21:53

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SPEC_O.jed

JEDEC fusemap for the PAL marked with an O.

jed - 702.00 bytes - 09/17/2025 at 21:53

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SPEC_O.GJD

Output of PAL2GAL for the PAL marked with an O.
This is what you can use to program a GAL16V8.

gjd - 671.00 bytes - 09/17/2025 at 21:53

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SPEC_Y.GJD

Output of PAL2GAL for the PAL marked with an O.
This is what you can use to program a GAL16V8.

gjd - 749.00 bytes - 09/17/2025 at 21:53

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Memotech Speculator_Schematic.pdf

For a different machine, but much in common. The Einstein has extra parts to emulate the Spectrum tape interface.

Adobe Portable Document Format - 100.30 kB - 09/11/2025 at 21:18

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Memotech Speculator Parts List.txt

May of these will be the same in the Einstein version.

plain - 196.00 bytes - 09/11/2025 at 21:18

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Memotech Speculator U3 equations.txt

This selects the 2k RAM in the Memotech's I/O map.

plain - 1.20 kB - 09/11/2025 at 21:18

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Memotech Speculator U4 equations.txt

This implements the logic of the 74LS148 which is an 8-input priority encoder. The encoder output forms an address for looking at the keyboard matrix in the RAM as seen from the Spectrum's I/O map.

plain - 1.06 kB - 09/11/2025 at 21:18

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