FPGA Timing Constraint Library

The timing
constraint repo that should have
existed years ago.

Annotated .xdc, .sdc, .lpf, and .cst templates for every interface — with the theory, formulas, and toolchain guidance engineers actually need.

View on GitHub Timing Calculator AI Generator CLI Engine

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XDC — VivadoSDC — Quartus LPF — nextpnrCST — Gowin EDA SPI Master + SlaveUART I2CDDR3 SDRAM LVDSHDMI TMDS RGMII EthernetMIPI CSI-2 AXI4-LiteI2S Audio CDC PatternsMulticycle Path XDC — VivadoSDC — Quartus LPF — nextpnrCST — Gowin EDA SPI Master + SlaveUART I2CDDR3 SDRAM LVDSHDMI TMDS RGMII EthernetMIPI CSI-2 AXI4-LiteI2S Audio CDC PatternsMulticycle Path

Diagnostic Engine New

Pre-Synthesis
Timing CLI

Run blazing fast structural timing diagnostics natively on your machine. Instant O(|V|+|E|) logic depth parsing, CDC detection, and fanout flagging directly from your IDE.

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Interfaces covered

Boards supported

Toolchain formats

Annotated files

Interactive tool

Timing Budget
Calculator

Paste datasheet values — tCO, tSU, tH — and get the exact set_input_delay / set_output_delay lines. Shows setup and hold slack with a visual timeline. No guessing what the formula is.

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AI-powered New

AI Constraint
Generator

Paste your Verilog or VHDL top-level module. The AI reads every port, identifies clocks and interfaces, maps pins to your board, and writes the complete constraint file in seconds.

Open AI Generator

constraint library

The timingconstraint repo that should haveexisted years ago.

The timing
constraint repo that should have
existed years ago.