Let me do some thread necromancy to ask about this very well known paragraph from Gideon's freezer document: "It was attempted to pull –DMA low around 250 ns before the falling edge of PHI2, so after the R/–W line had stabilized. This works perfectly on a 6510, but makes the 850x CPU in a C64c crash. Apparently, this CPU does not like to see RDY ‘true’ on a rising edge of PHI2, and ‘false’ on the subsequent falling edge." We have clocked hundreds of testing hours with BeamRacer running on several 8500s. Not a single crash, despite stopping and restarting the CPU exactly in this manner up to 200 times per frame. Has anyone actually experienced the issue described by Gideon? Could the fact that we are pulling down just the RDY (as opposed to RDY and AEC he had to manipulate jointly with the DMA line) have any significance? Thanks, Milek -- Sent from: http://cbm-hackers.2304266.n4.nabble.com/Received on 2020-06-13 06:02:05
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