memory products - Al Kossow's Bitsavers

MK4501(N,K)-65/80110112/15/20EXPANSION TIMINGFigures 10 and 11 illustrate the timing of the Expan·sion Out and Expansion In signals. Discussion ofExpansion Out/Expansion In timing is provided toclarify how Depth Expansion Works. Inasmuch asExpansion Out pins are generally connected onlyto Expansion In pins, the user need not be con·cerned with actual timing in a normal Depth Ex·panded application unless e~eme propagationdelays exist between the XC/XI pin pairs.Expansion Out pulses are the image of the WRITEand READ signals that cause them; delayed in timeby tXOL and tXOH' The Expansion Out signal ispropagated when the last physical location in thememory array is written and againwhen it is read(Last Read). This is in contrast to when the Full andEmpty Flags are activated, which is in response towriting and reading a last available location.FIGURE 10. EXPANSION OUT TIMING[ lLASTWRITE TOLAST PHYSICALLOCATIONVi '\_______-'1READ FROMPHYSICALLOCATIONR ~~ ____ ----,{m -9~!----f" ~'"i ~~JAC ELECTRICAL CHARACTERISTICS(O°CsTAs +70OC) (Vee = +5.0 volts ± 10%)SYM PARAMETER4501·65 4501·80txoL Expansion Out Low 55 70txoH Expansion Out High 60 804501·10MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX UNITS NOTES75904501-12 4501·15 4501-2090 115 150 ns100 125 155 ns10115406