Trs-80 model 1, level 1 rom differences

[mrthreeplates]

Hi,

Is there any differences between in the level 1 roms?

I see here there may be at least two versions

ROM Comparison Page (Model I) | Ira Goldklang's TRS-80 Revived Site

TRS-80 Revived Site by Ira Goldklang's is an archive of everything related to the Tandy Radio Shack TRS-80 microcomputer lines. Site contains emulators, programs, manuals, books, patches, games, hints, discussions, questions, forums, and tons more.

www.trs-80.com

I searched in vain, so would appreciate any insight.

Thanks,

 

[Eudimorphodon]

Alas I do not know. I do know there were *physical* differences between the earliest Level I ROMs and later, in at first it came as two 2Kbyte chips and was later repackaged into a single 4K, but no idea if that corresponds to any code differences.

The later 4K one was desirable for that hack where a switch was added to toggle between Level I and II because it could reside in the socket not occupied by the ribbon cable going to the satellite board.

 

[Trash-Eighty]

Beside the fact that the Model I and the Model III have different Level I ROM versions it seems that no official documented version change for the Model I was ever made - at least as I know.
You could ask Ira if he remembers where the two different checksums did come from.

The Level 1 ROM differences between the Model I and the Model III are described by George Phillips.

 

[rittwage]

I thought a later version had some key-debouncing code, but I am not 100% on that.

 

[gepooljr]

I have a Model 1 Level 1 with 4K. How would I know if the board version can run that hack mentioned above?