To review, the following chips were lumped together for analysis:
For the most part these were assumed to be a mix of Fujitsu DSPs. For example, here's an MB86233 (315-5571):
While the MB86234 (315-5677) is very close:
So what about the others?
Sega 315-5673 (#214)Here's the package:
Which has this die:
Which is clearly not one of the DSPs. Markings:
Sega 315-5672 (#217)Here's the package:
A bit suspicious since it has a wildly different number of pins than the others. Anyway, here's its die:
Which is also clearly does not look like the others. Markings:
Sega 315-5674 (#216)Here's the package:
Also a different package, it was suspected this wasn't like the others. And here's the die:
Confirming this. Markings:
SummaryThese chips are Fujitsu CG24 uncommitted logic arrays (ULAs). With the above new information, our Sega 315-XXXX table now has:
- 315-557X: Fujitsu MB86233 DSP
- 315-567X (lower): Fujitsu CG24 ULA
- 315-567X (higher): Fujitsu MB86233 DSP
As there is no firmware to document on these chips, no further work will be done at this time. If at some point it becomes feasible to capture the original layout, we'll revisit.
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