PhilC wrote: ↑Sat May 04, 2019 9:51 am
exxos wrote: ↑Sat May 04, 2019 12:09 am
Wonder if this would clock at 64MHz
Willing to bet we shall be finding out shortly
When I get the proper mod pcbs done, I will try it, but while the MMU may clock that speed, the GLUE is likely going to be the spanner in the works.
Ultimately, It would be good to have a FPGA core which includes MMU,GLUE,BLITTER. Though these cores are not 100% accurate, so even 8MHz modes are going to break stuff.
Probably the way to go is a future board to have the normal ST chipset, with a huge expansion header to replace those with the FPGA cores. Then the user can decide if they want max speed or max compatibility. This is assuming the suska cores. Ijor has another set of cores, but AFAIK they haven't been tested a great deal or are open source.. Similar with the suska cores, in that I don't think they have had much testing by anyone on a original setup. I know the suska core doesn't "support" wake up states, as Troed and I found out, his demos won't run on the suska cores.
Also FPGA cores mean people can add features or updates to them. I talked to Wolfgang last year about a tweak to the MMU core.. to basically allow a "fast block clear" direct to RAM. In that the CPU only sets start,end address, and block fill pattern. The MMU can clear a block of ram without involving the CPU or blitter for the actual data clearing. Tweaks to games or the OS could be done to use such a feature. As games use a lot of clearing , it should increase frame rates even on a stock 8MHz setup... Really just thinking out loud, but I think tweaking the cores to allow new features is a interesting idea...