[axytol]

As others have already mentioned the Lattice ice40 family is supported by OSS chains through project icestorm [0].

There were some nice boards floating around though you may have to watch out for supply chain issues still plaguing this market. Examples:

- icoboard: has the 8k LUTs chip, comes with soldered PMODs[1], if you get it watch out as you either need a RaspberryPI with GPIOs soldered to program it, or you purchase their USB FTDI interface in addition. See: http://icoboard.org/

- iCEBreaker, comes with the 5k LUTs chip, has the USB-FTDI interface built-in, but you need to solder the PMODs yourself. See: https://www.crowdsupply.com/1bitsquared/icebreaker-fpga#prod...

[0] https://github.com/YosysHQ/icestorm

[1] https://digilent.com/reference/pmod/start

[mediumdave]

I've had good experiences using Upduino 3.0 and 3.1 [0] with the IceStorm tools via apio [1]. I wrote a blog post [2] with some info on getting things set up via Linux. All you need is the Upduino board, which interfaces to your host system via USB (so no special programmer is needed).

[0] https://tinyvision.ai/products/upduino-v3-1

[1] https://github.com/FPGAwars/apio

[2] https://daveho.github.io/2021/02/07/upduino3-getting-started...

[JoachimS]

Lattice ECP5 devices are also supported by open tools.