Bitstream Compaction iCE40 - Bitstreams and Reconfiguration Time Measurements

The HDF5 file contains data from an experiment concerning bitstream compaction for Lattice iCE40 FPGAs.

Four projects were synthesized with two different toolchains and afterwards compacted in two different levels, resulting in 24 bitstreams. The creation of each bitstream was repeated 100 times to guard against variations caused by errors in the toolchains or by the compaction. No such errors occured and the configuration is the same for every repetition.

The reconfiguration time for each of the 24 bitstreams was measured 10.000 times.

Toolchains:

• Lattice iCEcube2
• Open Source Toolchain (Yosys, nextpnr, Project Icestorm)

Projects:

• empty: Completely empty project, that uses no FPGA resources.
• b12: A project from the ITC’99 benchmark suite.
• aes: A simple AES-128 encryption module.
• picosoc: RISC-V system on a chip

Compaction levels:

• original: uncompacted bitstream
• builtin: compacted with two methods also available in iCEcube2
• compact: compacted with all five methods

File structure:

The data is organzied hierarchical. It is first split between bitstreams and measurements, then by toolchain, then by project and finally by compaction level.