ASSIST-09-faded-output-LV.txt

Disassembly of the ROM data read at low VCC. Believed to be better than the one read at normal voltage, but has not been tested.

plain - 127.00 kB - 03/26/2026 at 04:06

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ASSIST-09-faded_info-LV.txt

Information for disassembling the ROM data read at low VCC.

plain - 5.24 kB - 03/26/2026 at 04:05

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ASSIST-09-faded-xor-hd.txt

Xoring the two ROM images, there are 457 bytes with just d0 different, 39 with just d1 different, and 10 with both d0 and d1 different.

plain - 7.78 kB - 03/24/2026 at 05:00

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x-diff.txt

Comparing the hex dump of the ROM at normal and minimum VCC, it is clear that the readable ASCII text is corrected, making me confident that the executable code is also much improved. Though there is still the risk that some bits have faded beyond recovery. Hopefully those are few enough to be deduced be educated guesswork.

plain - 21.92 kB - 03/24/2026 at 04:28

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AM2732A@DIP24.BIN

ASSIST-09-faded.BIN ROM read at minimum VCC, on a hunch that this would lower the internal bit-reading thresholds to give faded bits a better chance of being read.

octet-stream - 4.00 kB - 03/23/2026 at 20:26

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ASSIST09step02 (2).txt

hex dump edited to assemble on asm80.com online.
Sections are recognisable as code from assist09 source code.

plain - 47.11 kB - 03/18/2026 at 16:04

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ASISST09step01 (1).txt

a hex dump of the ROM, read and not edited

plain - 22.82 kB - 03/18/2026 at 16:04

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ASSIST-09-faded.BIN

octet-stream - 4.00 kB - 03/18/2026 at 16:08

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SSI4351_b5.txt

Steve Marsh's mystery ROM disassembly so far

plain - 60.75 kB - 10/03/2024 at 02:06

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SSI4351_b5.nfo

A few bits of information for the disassembler

x-nfo - 9.05 kB - 10/03/2024 at 02:06

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SSI4351_b5 Memory Map.txt

plain - 1.48 kB - 10/03/2024 at 02:42

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SSI4351_b5.BIN

Steve Marsh's mystery ROM

octet-stream - 4.00 kB - 10/01/2024 at 01:19

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J070-U11_EQN.txt

Initial analysis, NOT TESTED!

plain - 1.69 kB - 05/28/2022 at 16:18

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J070-U10_EQN.txt

Initial analysis, NOT TESTED!

plain - 2.36 kB - 05/28/2022 at 16:18

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J070-U9_EQN.txt

Initial analysis, NOT TESTED!

plain - 1.41 kB - 05/28/2022 at 16:18

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J070-U11-EQN.txt

output from jed2eqn

plain - 887.00 bytes - 05/28/2022 at 16:17

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J070-U10-EQN.txt

output from jed2eqn

plain - 1.11 kB - 05/28/2022 at 16:17

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J070-U9-EQN.txt

output from jed2eqn

plain - 883.00 bytes - 05/28/2022 at 16:17

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J070-SC09-V1I2-U11-MMI-PAL16L8A-CS4BD6.jed

jed - 2.76 kB - 02/11/2022 at 02:47

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J070-SC09-V1I2-U9-PAL16R6-CS4778.jed

jed - 2.76 kB - 02/11/2022 at 02:47

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J070-SC09-V1I2-U10-MMI-PAL16V8H-25-CS58A1.jed

jed - 2.96 kB - 02/11/2022 at 02:47

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Arcom_J070_SC09.pdf

User manual

Adobe Portable Document Format - 488.01 kB - 12/22/2021 at 00:46

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Sys6809.src.txt

Source code for Acorn System One 6809 board.
Potential foundation for Acorn-based software projects, such as a 6809 second processor firmware and BBC BASIC.

plain - 42.33 kB - 03/03/2024 at 16:24

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6809_SINTB.s.txt

Buffered Interrupt-Driven Input/Output Using a 6850 ACIA.
From Leventhal's 6809 Subroutines book.

plain - 11.19 kB - 09/13/2019 at 21:07

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Acorn_200_012_U4_works_commented_asm.txt

Source code for Acorn's System One 6809 board firmware.
Acorn style MOS and monitor, with code to bootstrap from floppy disc.

plain - 42.44 kB - 03/03/2024 at 16:24

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ExBasROM.asm.2019-06-01.zip

Extended BASIC for Grant Searle's Simple 6809 design, modified syntax so it can be assembled online. One-byte error corrected.

Zip Archive - 63.03 kB - 06/02/2019 at 16:13

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