Saturn processor die-shot

[Jonathan Busby]

I know as a *fact* that all the Yorke and Clarke SoCs ( and probably anything derived from them such as Bert ) use a PLA for at least most of the combinatorial logic in the embedded Saturn CPU, if not the rest of the chip -- I don't know if this is the case with the 1LK7. If it is the case then I'd expect to see a large regular grid for the AND plane and an abutting grid for the OR plane. In the die shot, the structure toward the upper left-hand corner looks like it may be a PLA.

On another note, if you're really into reverse engineering vintage ICs, I'd recommend a metallurgical microscope from AmScope as they're pretty affordable considering the alternatives and they are well suited to HP vintage ICs as even the Yorke SoC and Saturn were manufactured with a *HUGE* process technology ( we're talking something like 0.5 microns ).

Regards,

Jonathan