The C264Cart ist a modernized ROM cartridge for the Commodore 264 family of 8-bit computers, the Commodore C16, C116, and Plus/4.
I started out by first reverse engineering and replicating the layout of an original ROM cartridge. Then I adapted it to better suit EPROMS and EEPROMS that are still readily available today, such as the W27C512 and W27C020. The layout was also scaled down to save shipping costs, but still fits the original cartridge shells.
See my blog post for more details.
I also created a simplified version of the original cartridge case for 3D printing that works well with the C264Cart. It is currently available for personal use on Thingiverse and Printables.
There are two things that need to be configured, the type of EPROM to be used and the size of the targeted ROM images.
The C264Cart can be configured to support either 16k ROM images or 32k ROM images by setting JP6 and JP7 accordingly. 32k ROM images for the 264 computers usually consist of two 16k parts that were originally stored in two separate ROMs. On the C264Cart in 32k mode, both parts go into the same EPROM with the upper part directly following the lower one. As a result, A14 cannot be used for external bank switching in 32k mode. It is automatically selected by the cartridge.
If the C264Cart is configured for 16k mode R1, D1, and D2 don't need to be populated. These components are used in 32k mode, only.
The C264Cart supports 27C512, 27C020, and 27C040 (E)EPROMs. Make sure that these ICs are always aligned to the top of the cartridge as indicated on the silkscreen and that the jumpers JP4 and JP5 are set correctly!
Address | A14 | A15 | |
---|---|---|---|
0x0000 | ROM 1 | 0 | 0 |
0x4000 | ROM 2 | 1 | 0 |
0x8000 | ROM 3 | 0 | 1 |
0xC000 | ROM 4 | 1 | 1 |
Address | A14 | A15 | A16 | A17 | |
---|---|---|---|---|---|
0x00000 | ROM 1 | 0 | 0 | 0 | 0 |
0x04000 | ROM 2 | 1 | 0 | 0 | 0 |
0x08000 | ROM 3 | 0 | 1 | 0 | 0 |
0x0C000 | ROM 4 | 1 | 1 | 0 | 0 |
0x10000 | ROM 5 | 0 | 0 | 1 | 0 |
... | ... | ... | ... | ... | ... |
0x3C000 | ROM 16 | 1 | 1 | 1 | 1 |
Address | A14 | A15 | A16 | A17 | A18 | |
---|---|---|---|---|---|---|
0x00000 | ROM 1 | 0 | 0 | 0 | 0 | 0 |
0x04000 | ROM 2 | 1 | 0 | 0 | 0 | 0 |
0x08000 | ROM 3 | 0 | 1 | 0 | 0 | 0 |
0x0C000 | ROM 4 | 1 | 1 | 0 | 0 | 0 |
0x10000 | ROM 5 | 0 | 0 | 1 | 0 | 0 |
... | ... | ... | ... | ... | ... | ... |
0x7C000 | ROM 32 | 1 | 1 | 1 | 1 | 1 |
A14 must be left open!
Address | A14 | A15 | |
---|---|---|---|
0x0000 | ROM 1 low | x | 0 |
0x4000 | ROM 1 high | x | |
0x8000 | ROM 2 low | x | 1 |
0xC000 | ROM 2 high | x |
A14 must be left open!
Address | A14 | A15 | A16 | A17 | |
---|---|---|---|---|---|
0x00000 | ROM 1 low | x | 0 | 0 | 0 |
0x04000 | ROM 1 high | x | |||
0x08000 | ROM 2 low | x | 1 | 0 | 0 |
0x0C000 | ROM 2 high | x | |||
... | ... | x | ... | ... | ... |
0x38000 | ROM 8 low | x | 1 | 1 | 1 |
0x3C000 | ROM 8 high | x |
A14 must be left open!
Address | A14 | A15 | A16 | A17 | A18 | |
---|---|---|---|---|---|---|
0x00000 | ROM 1 low | x | 0 | 0 | 0 | 0 |
0x04000 | ROM 1 high | x | ||||
0x08000 | ROM 2 low | x | 1 | 0 | 0 | 0 |
0x0C000 | ROM 2 high | x | ||||
... | ... | x | ... | ... | ... | ... |
0x78000 | ROM 16 low | x | 1 | 1 | 1 | 1 |
0x7C000 | ROM 16 high | x |
USE AT YOUR OWN RISK!.
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