On Mar 4, 11:22 am, Jeff Walther <[email protected]> wrote: > > So: > > RAS CAS WE | WE_OUT > 0 0 0 | 1 > 0 0 1 | 1 > 0 1 0 | 1 > 0 1 1 | 1 > 1 0 0 | 0 > 1 0 1 | 1 > 1 1 0 | 1 > 1 1 1 | 1 > > And WE_OUT = RAS' OR CAS OR WE_IN > > So if WE_ doesn't need to be held low longer than CAS_ it looks like > one could do it with an inverter and two OR gates or an inverter and > one three input OR gate. > > Jeff Walther
Well, carp. All of the above was wrong. I looked at a memory datasheet. RAS stays low during the whole operation. So one needs a state machine which only let's WE go low if RAS went low first. If CAS went low first then WE must be kept high. I'm not quite sure how the state machine would reset, though. Maybe whenever RAS goes high again. Jeff Walther -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/
