ModuleWare Reference Guide - Hornad

Primitive PartsBufif1 Primitive (pbufif1)Bufif1 Primitive (pbufif1)This is a highly parameterized bufif1 primitive which has a scalar input anda scalar output. The functionality is controlled by a scalar input ena.The rise, fall and turnoff delays can be specified by separate enumeratedparameters rise_delay, fall_delay and turnoff_delay respectively.If there is no delay specification, there is no propagation delay through thegate.If turnoff_delay is not specified, the smallest of the rise and fall delays applies on outputtransitions to X and Z. If turnoff_delay is specified, it determines the delay of transitions to Z,and the smallest of the three delays determines the delay of transitions to X.The strength level can be controlled by the enumerated parameters strength0_type andstrength1_type. If strength0_type is not specified where strength1_type is specified,strength0_type is taken as Strong0. Whereas if strength1_type is not specified wherestrength0_type is specified, strength1_type is taken as Strong1.Some combinations of data input values and control input values cause these gates to output oneof the two values without a preference for either value. The logic table for this gate includes twovalues representing such unknown results. The value L is a result representative of a value of 0or Z. The value H is a result representative of a value of 1 or Z.Functiondout = buffered din if ena is logic 1Truth TableTable 10-9. Bufif1 Primitive Truth Tablepbufif1 Control0 1 X ZD 0 Z 0 L LA 1 Z 1 H HT X Z X X XA Z Z X X X238ModuleWare Reference Manual, Library Version 1.9September 18, 2008