ModuleWare Reference Guide - Hornad

Three-state Inverter (triinv)When enabled, the value of input port din is passed to the output port dout.When disabled, all of the bits in output port dout are set to Z.If the scalar port ena has positive polarity, the inverter is enabled when thevalue of port ena = 1. If ena has negative polarity, the inverter is enabledwhen the value of port ena = 0.This part is equivalent to n 1-bit tristate inverters, where n is the port width.Setting dout_type to ActiveLow results in a Three-state Buffer.FunctionFor every bit in the bus:Logic PartsThree-state Inverter (triinv)dout= din when enabled= Z when disabledTruth TableThis table is for positive polarity. For negative polarity, invert the values.Table 2-36. Three-state Inverter Truth Tabledin(i) ena dout(i)0 1 11 1 00 0 ‘Z’1 0 ‘Z’ParametersTable 2-37. Three-state Inverter ParametersParameter Values Defaultdin, dout Port width (must be > 0) Automaticdout_type, ena_type ActiveHigh, ActiveLow ActiveHighDesign Rule Checks• An error is issued if the width of any port cannot be determined, port ena does not have afixed width of 1 or if ports din and dout are not the same width.• A warning is issued and HDL generation fails for this part if any of the ports are notconnected.ModuleWare Reference Manual, Library Version 1.9 55September 18, 2008