Files | Isetta TTL computer

This is included in the microcode. The microcode will copy this to main RAM and start executing. The loader fetches "boot.bin" from serial flash and executes it. The loader can also fetch a file from the Raspberry Pi and start executing it. It has a few more functions.

octet-stream - 5.96 kB - 05/26/2024 at 16:39

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Isetta Z80 instruction cycles.pdf

Number of cycles for each instruction, compared to the number of the classic Z80

application/pdf - 108.86 kB - 05/03/2024 at 09:49

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Isetta 6502 instruction cycles.pdf

Number of cycles for each instruction, compared to the number of the classic 6502

Adobe Portable Document Format - 91.32 kB - 05/03/2024 at 09:48

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generated microcode 240419.txt

Readable microcode for 6502, Z80, Isetta reset and device drivers.

plain - 347.98 kB - 04/20/2024 at 09:52

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isetta milestone 240419

Raspberry Pi Python3 program, to program the microcode flash chips, and to provide character I/O for Isetta. Milestone 240419 is the first time Apple basic runs on Isetta hardware (using RPi for character I/O).

isetta milestone 240419 - 36.50 kB - 04/19/2024 at 17:30

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microcode bin 240419B.txt

Binary (hex format) version of microcode

plain - 896.01 kB - 04/19/2024 at 15:22

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Isetta 20230610.pdf

First version of schematic.

Adobe Portable Document Format - 2.17 MB - 06/11/2023 at 13:31

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microcode 230421_new.txt

First version of 6502 microcode generator.

plain - 39.04 kB - 04/21/2023 at 20:55

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ucode1203 ucode1203 - 896.01 kB - 12/03/2025 at 13:09		Download
sym1202E.bin octet-stream - 127.58 kB - 12/02/2025 at 14:59		Download
sym1202D.bin octet-stream - 127.58 kB - 12/02/2025 at 14:44		Download
sym1202C.bin octet-stream - 127.58 kB - 12/02/2025 at 14:36		Download
sym1202B.bin octet-stream - 127.58 kB - 12/02/2025 at 13:46		Download
ucode1202 ucode1202 - 896.01 kB - 12/02/2025 at 13:36		Download
sym1202A.bin octet-stream - 127.58 kB - 12/02/2025 at 10:47		Download
sym1202.bin octet-stream - 127.58 kB - 12/02/2025 at 10:34		Download
sym1201B.bin octet-stream - 127.58 kB - 12/01/2025 at 19:53		Download
ucode1128 ucode1128 - 896.01 kB - 11/28/2025 at 20:46		Download
sw_pack251119.zip Zip Archive - 13.72 MB - 11/19/2025 at 10:24		Download
isetta_rpi_251117 isetta_rpi_251117 - 63.00 kB - 11/19/2025 at 09:51		Download
sw_pack251004.zip Zip Archive - 13.71 MB - 11/10/2025 at 10:41		Download
assy dwg ISA2532 upper half components.png Portable Network Graphics (PNG) - 173.04 kB - 10/03/2025 at 15:16		Preview

assy dwg ISA2532 upper half capacitors.png Portable Network Graphics (PNG) - 128.17 kB - 10/03/2025 at 15:16		Preview

assy dwg ISA2532 lower half components.png Portable Network Graphics (PNG) - 142.47 kB - 10/03/2025 at 15:16		Preview

Schematic Isetta ISA2442.pdf The almost-latest schematic Adobe Portable Document Format - 2.38 MB - 10/02/2025 at 19:50		Preview

ucode1002 ucode1002 - 896.01 kB - 10/02/2025 at 15:06		Download
Isetta programming manual 250823.txt plain - 28.49 kB - 08/23/2025 at 17:35		Download
psg250617.z80 z80 - 60.49 kB - 06/17/2025 at 14:36		Download
sounddaemon-isa.zip x-zip-compressed - 17.79 kB - 06/08/2025 at 14:19		Download
os2hex.py3 py3 - 6.84 kB - 05/13/2025 at 08:04		Download
os250513.bin octet-stream - 127.61 kB - 05/13/2025 at 07:00		Download
bin2hex_v2.py3 py3 - 6.84 kB - 01/26/2025 at 11:45		Download
boot 241221A.z80 Today's stable operating system version. Source code.<br>Will automatically get loaded after reset. z80 - 114.23 kB - 12/21/2024 at 13:37		Download
boot.bin octet-stream - 17.87 kB - 12/08/2024 at 17:51		Download
loader 241206A.z80 z80 - 105.98 kB - 12/06/2024 at 21:43		Download
loader 241206.bin octet-stream - 6.36 kB - 12/06/2024 at 21:37		Download
apple1.woz Executable for Isetta. It switches from Z80 to 6502 instructions and runs the original Apple 1 BASIC. woz - 9.66 kB - 07/11/2024 at 20:54		Download
tge bin 240622A.txt The Great Escape, Isetta executable for this ZX Spectrum game. plain - 135.01 kB - 06/22/2024 at 07:11		Download
mm.z80 Manic Miner, original source code for this ZX Spectrum game. z80 - 345.95 kB - 06/09/2024 at 09:47		Download
altair8.bin The original Microsoft 4k Altair BASIC, with small changes in I/O to run on Isetta. octet-stream - 8.99 kB - 06/02/2024 at 19:39		Download
isetta-bu12-240531.py3 py3 - 48.82 kB - 06/01/2024 at 20:06		Download
loader 240526.bin This is included in the microcode. The microcode will copy this to main RAM and start executing. The loader fetches "boot.bin" from serial flash and executes it. The loader can also fetch a file from the Raspberry Pi and start executing it. It has a few more functions. octet-stream - 5.96 kB - 05/26/2024 at 16:39		Download
Isetta Z80 instruction cycles.pdf Number of cycles for each instruction, compared to the number of the classic Z80 application/pdf - 108.86 kB - 05/03/2024 at 09:49		Preview

Isetta 6502 instruction cycles.pdf Number of cycles for each instruction, compared to the number of the classic 6502 Adobe Portable Document Format - 91.32 kB - 05/03/2024 at 09:48		Preview

generated microcode 240419.txt Readable microcode for 6502, Z80, Isetta reset and device drivers. plain - 347.98 kB - 04/20/2024 at 09:52		Download
isetta milestone 240419 Raspberry Pi Python3 program, to program the microcode flash chips, and to provide character I/O for Isetta. Milestone 240419 is the first time Apple basic runs on Isetta hardware (using RPi for character I/O). isetta milestone 240419 - 36.50 kB - 04/19/2024 at 17:30		Download
microcode bin 240419B.txt Binary (hex format) version of microcode plain - 896.01 kB - 04/19/2024 at 15:22		Download
Isetta 20230610.pdf First version of schematic. Adobe Portable Document Format - 2.17 MB - 06/11/2023 at 13:31		Preview

microcode 230421_new.txt First version of 6502 microcode generator. plain - 39.04 kB - 04/21/2023 at 20:55		Download