Yosys + nextpnr
Synthesis
Fig: Netlist nodes mapped through a placement-routing grid to FPGA
Open-source synthesis + P&R toolchain supporting iCE40, ECP5, Nexus and more.
Open-Source Toolchain Flow
The whole flow avoids vendor EDA: Yosys synthesizes Verilog into a gate-level netlist, nextpnr performs placement, routing and timing optimization using open bitstream databases, then emits bitstreams for iCE40, ECP5, Nexus and other chips — ideal for fast iteration without vendor tools.
Fig: Yosys synthesis → nextpnr place & route → open FPGA bitstream