On Feb 24, 2014, at 7:51 PM, Jim Brain <brain@jbrain.com> wrote: > This time, it's PLA replacements. > > After fitting, the C64 PLA equations take only a nominal portion of the xc9536(xl) space I stuffed them into. And, none of the 36 registers are used. > > I know SuperPLA put a bunch of equations in the unit, for different products, but I was wondering... > > Are there any memory mappings that would have been nice to have via the PLA, but are not available? (external KERNAL at $e000, for instance?) > Yes, I understand compatibility and all that. But, if you had a switchable PLA, what new modes would be of interest? (are there any?) A couple (jim)brainstorms: 1. If there are multiple versions of the PLA, logic to switch to a given version, based on user writes to reserved combinations of address 0/1. 2. Add a very small VIC coprocessor where 6502 instructions are packed into your CPLD registers and scan line is detected via the VIC address patterns. You know, an Amiga-like copper in a C64. -Nate Message was sent through the cbm-hackers mailing listReceived on 2014-02-25 05:01:36
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