LFSR, PRBS & CRC

CRC-32 Generator (lfsr_crc)

Byte-serial CRC-32 generator with Ethernet-style polynomial, init 0xFFFFFFFF, and zlib-compatible output.

Open in IDE Category

About this block

Simulate it in the Verilog IDE

Hardverilogsimsyn

CRC-32 Generator (lfsr_crc) is a Verilog reference block in the LFSR, PRBS & CRC catalog. LFSR, PRBS, CRC, and pseudo-random sequence generators. Marked Hard: a larger reference. Simulate the packaged testbench before you change the RTL.

This IP implements a byte-serial CRC-32 generator using Alex Forencich's parametrizable lfsr_crc wrapper and combinatorial lfsr engine.

Default parameters match Ethernet-style CRC-32: polynomial 0x04C11DB7, initial value 0xFFFFFFFF, LSB-first input (REVERSE=1), and inverted output (INVERT=1).

Top module: lfsr_crc
Polynomial: 32'h04C11DB7
Init state: 32'hFFFFFFFF
Data width: 8 bits per clock when data_in_valid is asserted
Configuration: Galois, LSB-first, inverted CRC output compatible with zlib.crc32

Choose Open in IDE. RTL Studio loads the packaged workspace for CRC-32 Generator (lfsr_crc).
Read the Verilog module in the editor. The catalog line for this block: Byte-serial CRC-32 generator with Ethernet-style polynomial, init 0xFFFFFFFF, and zlib-compatible output.
Run the packaged testbench with the in-browser Verilator simulator, then open the VCD in the waveform viewer.
Run Yosys in the same IDE for a generic netlist. Sky130 liberty mapping is a separate Pro library option.

RTL Studio is the Verilog simulator and IDE around this block: Slang lint, Verilator, VCD waveforms, and Yosys, in the browser. Simulation guide · Yosys guide.

Interface

Signal	Direction	Width	Description
`clk`	Input	1	System clock
`rst`	Input	1	Synchronous reset; clears output and reloads LFSR init
`data_in`	Input	8	Input data byte
`data_in_valid`	Input	1	Advance CRC with `data_in` on rising clock edge
`crc_out`	Output	32	Registered CRC result (`~state` when `INVERT=1`)

Verification

Run simulation from this directory:

Test vectors include the standard 123456789 CRC-32 value 0xCBF43926.

More in LFSR, PRBS & CRC

All LFSR, PRBS & CRC blocks