Re: IEEE-488 bus

christianlott1 wrote:

Even with the 1541 mod, this doesn't seem like it would break
compatibility for software that don't use custom fastloaders? (yeah,
that's a question...)
Given the environment, I wouldn;t even hazard a guess.

Creating a motherboard with such features with sockets for the CIAs,
6510, VIC2, SID etc.. This would doubtlessly be very expensive?
(another question..)

Too expensive given the other options.

Assuming that any new board needs to include all ports (to make it usable anywhere the existing C64 was usable) rom of some kind and ram, you need to include board space for all of that in any design

But, a socketed board needs at least 4 40 pin sockets (2" x 2.8" sq in), plus room for 1 or 2 SIDs (1.5" * .7" sq in * 1 or 2), but you also need glue logic (assume a high density CPLD or FPGA to include all gates and PLA logic).

Assuming ports and analog logic go on 8sq inches of board, you're probably at 20sq inches (4x5 or so). Not bad.

But, then you look at a design that only needs a FPGA. No sockets are needed, so 8sq inches or so disappear. Since you needed a CPLD or FPGA for either design, you're not adding much space to use a larger one. At this point, the 8 sq inches of connectors dominate the design.

Still, if the market would bear the former, since it's easier to design, I'd be happy to draw up the board. However, I think it'd be tough to achieve consensus on the board dimensions. Some will want a board that fits in a C64 case, which would require an 'L' shaped board about 14" by 4" with about 1.5" of PCB along the L shape.

But, the modders would hate that board design, as they'd be happy with an exp port, 2 joyports, serial, video and a stubbier layout. The 4x5 board would suit them better.

Note that this issue exists no matter the technology used (FPGA or real ICs)

Thus, I think the larger issue of a smaller board is determining the market and what they want.

Jim

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