Floret

small flower buds at the head of a piece of broccoli.

Floret is an automated custom cell generator. The underlying algorithms are built from the following papers:

1. Stauffer, André, and Ravi Nair. "Optimal CMOS cell transistor placement: a relaxation approach." 1988 IEEE International Conference on Computer-Aided Design. IEEE Computer Society, 1988.
2. Chen, Howard H., and Ernest S. Kuh. "Glitter: A gridless variable-width channel router." IEEE transactions on computer-aided design of integrated circuits and systems 5.4 (1986): 459-465.
3. Deutsch, David N. "A “Dogleg” channel router." Papers on Twenty-five years of electronic design automation. 1988. 111-119.

Build and Install

Install all dependencies

sudo apt install libqhull-dev zlib1g-dev python3.10-dev
git submodule update --init --recursive

There are two build systems supported. Tup is preferred, placing floret-linux into the build-linux directory

tup init
tup

However, we also a Makefile set up, placing floret-linux into the root directory

make

Examples

See Releases for example generated layouts.

This will generate a GDS library with a nand gate in test.gds called test using the sky130 tech file provided in the tech directory.

build-linux/floret-linux --gds test test.gds tech/sky130.py test/nand.spi

This will generate directory called cells and create a .rect file with a nand gate layout using the ACT layout.conf and prs2net.conf files in the specified directory.

build-linux/floret-linux --rect cells /opt/cad/conf/sky130 "tech/actconf.py /opt/cad/conf/sky130" test/nand.spi

Status

Floret is being tested on Skywater's 130nm process technology node. It is not yet producing DRC clean layouts, but the layouts are often workable with minor manual alterations.