Posted By
RetroAndMore
on 2024-07-17
07:23:37
|  Re: Hardware project for C16 and C128
@SukkoPera:
Yes, and exactly this is the fact I don't understand. Why is everybody replicating boards which are already existing? A replica mainboard of the A500 for 60 USD. These things are existing, why replicating those? Why did not anybody try to make a replica of the C65 board and reverse-engineer the custom chips? That would be useful.
There are so many modifications which could be made. There's a 1581 replica board, but only with a mod to use a PC floppy. Why not making everything more interesting? My plans for a new 1581-compatible 3,5" drive would be:
- Instead of the 8520 a VIA 65C22, these are still prodouced
- Instead of the 6502 a WDC 65C816, these are also still produced
- Both IC's are fully static, available in PLCC format for smaller design and work up to 14 MHz
- If the original WD1772 FDC is used, this chip supports up to four drives
- The 65C816 can access up to 16 MB RAM, allowing 16 1581-sized RAM disks
- These RAM disks can be buffered by a battery
The ROM should be used as close to the 1581, changing only the VIA/CIA routines. A ROM addon should support new formats: 1581, 720K and 1,44 MB FAT12 disks and a new native format with subdirectories and the usual 16-character names. FD-2000 compatibility isn't neccessary because these drives are too rare. It should be possible to create all formats as RAM disks. These are accessed by unit numbers, but a specific floppy/ramdisk can be set as unit 0. A drive like this will be more compatible than any SD-interface for mounting d64-images and if only If only standard components like 74xx and 65xx are used, it is cheaper than a 1541 Ultimate.
The VDC is closer to the TED because both have the problem having no sprites. But correctly programmed, they could do amazing things. TED-FLI looks amazing. VDC-FLI is also great, and in much higher resolution. The main problem of the VDC, the indirect programming, could be solved with my hardware. Amazing would be a genlock, with the VDC transparent on top of the VIC or TED.
You wrote 'Please do not do duplicate work', but integrated a 512kB RAM-expansion by Hannes, and SID-expansions for the plus/4 also were existing. Isn't that duplicating work? And I guess there are different SID cartridges and memory upgrades, which were never regularly used.
My project is a clean project, because it is designed as a pure upgrade project for original hardware. The expansion port stays free, and it only requires a few bytes in memory. I know the problems of the SuperCPU and the Flash8: Great hardware, but you couldn't use it. That's why I planned from the beginning the capability for a new ROM, best containing modern routines from the demoscene. And these routines should be able to be used from BASIC.
I'm wondering that nobody is interested in upgrading all available machines with low cost.
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