Attached are soft dumps. Of the 040 PDS cards, only the 100mhz daystar cards would have the ability to change it as the 66mhz cards don't use the ICS chip with adjustable multipliers nor do they have the empty footprint as the turbo 601 does. Haven't checked for differences but I would be particularly interested in the early initialization code (post-reset) and to a lesser degree the common video primaryinit and then driver load for RBV.
2.5f1 7C810464
2.5f2 7C4F0317
Moreover the 66mhz cards don't have the ICS PLL at all so they're stuck with 2x and cannot be upgraded to 100mhz. I would be interested if a 100mhz board modified to a 4x jumper has the same apparent race condition at initialization the T601 seems to have (currently). Some boots it comes up fine, others are no-chime, but a full power cycle is required to retry. An Interesting finding on the initialization issue: it also affects 030 boots, suggesting it's something with the card's initial power up sequence, maybe that mystery ARM core?
No; if you decouple the buses you have to synchronize in both directions always (= added delay) on *any* bus transaction and require bidirectional registered transceivers (= expense) on your data bus. With both 601 and 040 buses being synchronous it makes sense to run them in lockstep. Only if there's a major difference in clock speed or bus architecture does it make sense to run differently clocked busses, as is seen in the case of 040 accelerators in 030 systems.
