ModuleWare Reference Guide - Hornad

Sequential PartsParallel to Serial Shifter (shiftps)This part is equivalent to a shift register. This part has n Flip-Flops and shifter logic as per theshift operations (where n is the width of the input port din). Based on the parameterized statethe performance of the shift register can be accurately estimated.If clk_en is not connected, it is driven by 1. If the clock enable feature is not used, the scalarinput port clk_en must be unconnected and the parameter clk_en_type must be set toActiveHigh. Port clk_en can also be driven by an active driver, in which case the clk_en_typemust be correctly adjusted. The HDL code for clk_en is optimized away if it is not used.If the reset functionality is not used, do not change the value of the parameter rst_type.Note that even though the shift register can operate with only the reset operation, a warning isgiven if data is not being loaded. This is because the shift register is used mostly through theloaded value and it is assumed that there are missing connections. This warning can be ignored,if only the reset operation is required.Parameter rst_val can take LNBF format as described in the Constant Value (constval) model.Functioninternalregthe internal register.If reset is synchronous, then at every enabled clk trigger (rising edge if clk_type = Rising;falling edge if clk_type = Falling):internalreg= rst_val= din= internalreg >> 1= internalreg > 1= internalreg