1 - Al Kossow's Bitsavers

GLOSSARY!TIMING CONVENTIONS/DATA SHEET STRUCTUREThe hyphen between the Band C subscripts is omitted when no confusion is likely to occur.For examples of symbols of this type, see TMS 4116 (e.g., tpLCU.Classified time Intervals (general comments, specific times follow)Because of the information contained in the definitions, frequently the identification of one or both of the two signalevents that begin and end the intervals can be significantly shortened compared to the unclassified forms. For example,it is not necessary to indicate in the symbol that an access time ends with valid data at the output. However, ifboth signals are named (e.g., in a hold time), the from-to sequence is maintained.Access timeThe time interval between the application of a specific input pulse and the availability of valid signals at an output.Example symbology:ClassifiedUnclassifiedDescriptiontalA)·tatS), ta(CS)Cycle timetAVOVtSLOVAccess time from addressAccess time from chip select (low)The time interval between the start and end of a cycle.NOTE:Example symbology:NOTE:ClassifiedThe cycle time is the actual time interval between two signal events and is determined by the system inwhich the digital circuit operates. A minimum value is specified that is the shortest interval that must beallowed for the digital circuit to perform a specified function (e.g., read, write, etc.) correctly.tc(RI, tc(rd)tc(WIUnclassifiedtAVAV(R)tAVAV(W)DescriptionRead cycle timeWrite cycle timeR is usually used as the abbreviation for "read"; however, in the case of dynamic memories, "rd" is usedto permit R to stand for RAS.Disable time (of a three-state output)The time interval between the specified reference points on the input and output voltage waveforms, with the threestateoutput changing from either of the defined active levels (high or lowl to a high-impedance (offl state.Example symbology:Classifiedtdis(S)tdis(W)UnclassifiedtSHOZtWLOZThese symbols supersede the older forms tpvz or tpXZ.Enable time (of a three-state outputlDescriptionOutput disable time after chip select (high)Output disable time after write enable (low)The time interval between the specified reference points on the input and output voltage waveforms, with the threestateoutput changing from a high-impedance (off) state to either of the defined active levels (high or low).NOTE: For memories these intervals are often classified as access times.Example symbology:Classifiedten(SL)UnclassifiedtSLOVDescriptionOutput enable time after chip select low...(1)(1).cen~...~C-t/)Co'';::;c(1)>CoUC)c'si=->...~t/)t/)o(5These symbols supercede the older form tpZV.TEXAS INSTRUMENTSINCORPORATED3-5POST OFFICE BOX 225012 • DALLAS. TEXAS 75265