Cart Image Confusion
Posted: Wed Nov 08, 2017 10:15 am
Greets!
I am working on a project that fills an SRAM with a binary cartridge image and then boots the VIC.
So far my tests have worked, based on the information presented here...
http://comp.sys.cbm.narkive.com/0WNJAHD ... dge-format
What this indicates is...
Bytes 0,1 are the cold start program entry address.
Bytes 2,3 are the warm reset entry point address.
Bytes 4-8 are the sectret "a0CBM" auto start key (41 30 C3 C2 CD).
But I am starting to believe that this information is not correct.
In fact, every single 8K cart image I look at has an extra two bytes before the key.
Here is an example...
All of the images have 6 bytes before the secret key.
I have looked at many of the 8K ROMS from Zimmers, and they are all the same.
Can anyone shed light on this?
Either the info out there is wrong, or my HEX editor is playing tricks on me!
Thanks,
Brad
I am working on a project that fills an SRAM with a binary cartridge image and then boots the VIC.
So far my tests have worked, based on the information presented here...
http://comp.sys.cbm.narkive.com/0WNJAHD ... dge-format
What this indicates is...
Bytes 0,1 are the cold start program entry address.
Bytes 2,3 are the warm reset entry point address.
Bytes 4-8 are the sectret "a0CBM" auto start key (41 30 C3 C2 CD).
But I am starting to believe that this information is not correct.
In fact, every single 8K cart image I look at has an extra two bytes before the key.
Here is an example...
All of the images have 6 bytes before the secret key.
I have looked at many of the 8K ROMS from Zimmers, and they are all the same.
Can anyone shed light on this?
Either the info out there is wrong, or my HEX editor is playing tricks on me!
Thanks,
Brad