system verilog testband for parallel to serial converter

Note Because this example includes an asynchronous clear XST will not infer SRL16. The following table shows pin definitions for an 8-bit shift-left register with a negative-edge clock, clock enable, serial in, and serial out.įollowing is the VHDL code for an 8-bit shift-left register with a positive-edge clock, asynchronous clear, serial in, and serial out.įollowing is the Verilog code for an 8-bit shift-left register with a positive-edge clock, asynchronous clear, serial in, and serial out.Įndmodule 8-bit Shift-Left Register with Positive-Edge Clock, Synchronous Set, Serial In, and Serial Out Note For this example, XST will infer SRL16E_1.

Signal tmp: std_logic_vector(7 downto 0) įollowing is the Verilog code for an 8-bit shift-left register with a positive-edge clock, serial in, and serial out.Įndmodule 8-bit Shift-Left Register with Negative-Edge Clock, Clock Enable, Serial In, and Serial Out The following figure shows the pin layout of SRL16E.įollowing is the VHDL code for an 8-bit shift-left register with a positive-edge clock, serial in, and serial out. Both are available with or without a clock enable. Ĭonsult the VHDL/Verilog language reference manuals for more information.īefore writing Shift Register behavior it is important to recall that Virtex, Virtex-E, Virtex-II, and Virtex-II Pro have specific hardware resources to implement Shift Registers: SRL16 for Virtex and Virtex-E, and SRLC16 for Virtex-II and Virtex-II Pro.

predefined shift operators for example, sll, srl.There are different ways to describe shift registers. parallel: the contents of one or several of flip-flops other than the last one, is accessed.serial: only the contents of the last flip-flop is accessed by the rest of the circuit.In general a shift register is characterized by the following control and data signals, which are fully recognized by XST:

System verilog testband for parallel to serial converter