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Honored Contributor
Honored ContributorALTSHIFT_TABS automatically inserted into the design
I had the following in my design: r_reg1 <= { r_reg1, inputpin }; Then I had to introduce a condition to select which register input data will be shifted into, I did it this way: i...
Altera_ForumHonored Contributor
Honored ContributorI found the solution.
Assignments -> Settings -> Analysis & Synthesis settings -> Auto shift register replacement=OFF. --- Quote Start --- To infer shift registers, synthesis tools detect a group of shift registers of the samelength and convert them to an ALTSHIFT_TAPS megafunction. To be detected, all theshift registers must have the following characteristics: ■ Use the same clock and clock enable ■ Do not have any other secondary signals ■ Have equally spaced taps that are at least three registers apart --- Quote End --- --- Quote Start --- If theAuto Shift Register Recognition setting is set to Auto, Quartus II integratedsynthesis uses the Optimization Technique setting, logic and RAM utilizationinformation about the design, and timing information from Timing-Driven Synthesisto determine which shift registers are implemented in RAM blocks for logic. --- Quote End --- From the Altera's guide "6. Recommended HDL Coding Styles".
