cbmeeks wrote:My original point was that I was surprised that a drop-in replacement for the VIC-1 or VIC-2 haven't been done (yes, with FPGA) because the C64 and VIC-20 are so popular in the retro scene.
I am not surprised at all.
Last year, Sylvain, Fredric and i did develop a replacement for the 6526/8520/8521 CIA used in the C64, C128, C128D, 1571, 1581 and Amiga line of computers. This is probably a chip replacement which would be popular because it is used in a bunch of devices and computers Commodore made.
Cloning the CIA requires more than 200 macrocells and we were able to fit it in a pair of XC95144XL of 100 pins each. The size of these chips (sorry I can't solder the BGA form factor) is about 15mm wide and a pair of them required a larger board than can fit over a 40 pin DIP socket.
With the 2 CPLDs, the board, the 40 pin header and the work involved, the cost per unit to the customer of such a contraption was around 45$US per unit. Nobody would buy that.
I can easily imagine a VIC-I replacement costing around 90$US per unit and double that for the VIC-II. It is a near certitude this replacement will be slightly bigger than the original chip (as is the case with the TMS replacement) and this certainly cause some problems.
Before somebody invests thousands of dollars to develop this sort of product, one has to think how long it will take, if ever, to recover your investment and profit from it.