I am working on a memory card that uses 3.3v FeRam(FM28V100-TG) in place of 5v sram. I got the card to work, except that I get large amount of data corruption. After tracing the problem with the scope I narrowed it down to data writes. Whenever 5v side is driving 3v side I getting very noisy data. See pic. There is no noise when 3v drives 5v. I removed the FeRam to isolate the problem. First, I tried to tie DIR pin to high and the noise level decreased, but still noticeable Then, I tied OE# pin to low and DIR pin to high and data line is clean. Somehow, control signals cause the noise, but control signals themselves look clean on the scope.
Any ideas?
Any ideas?