Hallo Gerrit, > The LE-signal for the 74HCT573 is connected to _RAS. The OR-Gate takes > _RAS and _CAS as inputs and the output is the _CS signal for the SRAM. > In theory, just _CAS should work, but it doesn't, the system crashes, > possible due to _CAS being run through the PLA and _RAS going inactive > before _CAS does. > > With the OR-Gate the circuit works. I don't understand this. Using an OR gate means that _CS is only active LOW when as well _CAS as _RAS are LOW. Then why doesn't _RAS alone work? I cannot image that _RAS starts to early. IMHO it will become LOW after every flank of PHI2. If you has said you ANDed both signals, I would have taken that for granted immediately. -- ___ / __|__ / / |_/ Groetjes, Ruud Baltissen \ \__|_\ \___| http://Ruud.C64.org Message was sent through the cbm-hackers mailing listReceived on 2012-09-12 19:00:54
Archive generated by hypermail 2.2.0.