On Sun, Jul 19, 2020 at 5:05 AM Jeffrey Birt <birt_j_at_soigeneris.com> wrote: > > It seems this mod was not done on the original Rev 6 PCB but only on Rev7. The only difference I could see when comparing two Rev7 boards, is that the one with the mod board has slower, 200ns, DRAM. that might be the reason to lengthen the /RAS pulse. According to DRAM datasheets (for example the MCM4164), the low /RAS pulse needs to be 150ns min or 200 ns minimum, depending on the DRAM speed (150ns VS 200ns grade). Measuring the original /RAS low pulse length would give the final answer (if it's < 200ns or not). FrankReceived on 2020-07-19 10:00:02
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