An Open Implementation Flow for the Xilinx Spartan-3E and Spartan-6 that Runs in the Browser, Checked Byte for Byte Against ISE

arXiv:2611.13008v1 Announce Type: new Abstract: The author describes an open implementation flow, from HDL to a programmable bitstream, for the Xilinx Spartan-3E (XC3S100E to XC3S1200E) and Spartan-6 (XC6SLX16, XC6SLX45), devices that only the discontinued ISE 14.7 supports. The flow runs unchanged in a web browser or in Node.js: Yosys and nextpnr compiled to WebAssembly, with nextpnr's Himbaechel framework given Spartan-3E and Spartan-6 architectures generated from Silinx's own device descriptions, bit database and timing model, and Silinx's own bitstream writer.