[Coco] Help with Nitros9 on SDC?

[Don Barber]

Ah nice. Its suprisingly hard to find a datasheet for the MT1259-15 
chip, but from what I can discern it is a 150ns chip. Anyone have 
suggestions for a 120ns replacement?

Thanks,

Don

On 1/26/22 18:08, L. Curtis Boyle wrote:
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>     It could very well be RAM speed. 6309 EOU runs in 6309 native mode, which does run faster including a cycle out of accessing the RAM. I do remember that 150 ns RAM chips were hit or miss on the Coco 3 - some would work ok, others would have lock-ups, junk on the screen (especially when using hardware scrolling,etc.) . Once RAM upgrade manufacturers upgraded to 120 ns most of those problems went away. I know we had to take a few minor speedups out in the final versions of the original NitrOS-9 (back in the early 1990’s) because the GIME itself had difficulties with faster access to it’s registers while in the middle of the vector page RAM and/or GIME I/O access.
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