ULX3S board hardware (emard__ulx3s)

Field	Value
Upstream	https://github.com/emard/ulx3s
Reviewed at	6a92cec (upstream date 2025-04-27), reviewed 2026-09-27
License	Modified MIT (LICENSE.md): EMARD, RADIONA and FER logos must stay on the top silkscreen
HDL / framework	None (hardware project). KiCad 4 up to v1.8, then KiCad 5; opened/saved with KiCad 7 in 2023
Toolchain	n/a for gateware; the manual documents the open ECP5 flow (see below)
Programmer	Documented: openFPGALoader, fujprog/ujprog, OpenOCD, FleaFPGA-JTAG, ESP32, DFU
Target FPGA(s)	LFE5U-12F / 25F / 45F / 85F, CABGA381
Board revision(s)	v1.7 → v3.1.7 (tags v3.0.6 … v3.1.7)
Activity	2732 commits, 2016-01-28 → 2025-04-27. Hardware frozen since v3.1.7 (2021); recent commits are docs only

What it provides

• PCB design: ulx3s.pro, ulx3s.sch + sub-sheets (analog, blinkey, flash, gpdi, gpio, power, ram, serdes, usb, wifi), ulx3s.kicad_pcb, gerbers in plot/.
• BOM: doc/ulx3s_bom.csv, 1-click-bom.tsv (Kitspace), doc/MINIMAL.md for hand assembly.
• Schematics PDF: doc/schematics.pdf → schematics_v316.pdf (v308…v317 also present).
• Constraint files (the part that matters for gateware):
  • doc/constraints/ulx3s_v20.lpf: PCB v2.x.x and v3.0.x
  • doc/constraints/prototype/ulx3s_v17patch.lpf, ulx3s_v314.lpf, ulx3s_v316.lpf
• ECP5 pinout CSVs for all densities (doc/ECP5U*Pinout.csv), BGA381 package doc.
• User manual: doc/MANUAL.md (connectors, power/sleep, every programming method, ESP32 setup, displays, add-on modules, board revision history and production table).
• Enclosure: parametric OpenSCAD box in box/ (snapbox recommended).
• doc/TODO.txt: upstream hardware TODO list (not yet reviewed here).

Structure

Top-level KiCad project, doc/ for documentation/constraints/datasheets, plot/ for gerbers, footprints/, spice/, tools/, pic/ for photos, old/ for earlier versions.

How to build

Not a gateware project. PCB: kicad ulx3s.pro; gerbers: gerbv -p plot/ulx3s.gvp, zip -r /tmp/ulx3s.zip plot/ulx3s for fabs (IPC class 3, 5/5 mil, 0.2 mm holes).

Reuse notes

• Start any new design from the LPF matching the board revision; see docs/board-reference.md for the condensed pin/peripheral reference.
• The signal names in ulx3s_v20.lpf (clk_25mhz, led, btn, gp/gn, gpdi_dp/dn, sdram_*, usb_fpga_*, wifi_*, audio_*, oled_*, sd_*, adc_*, shutdown, …) are the de-facto top-level port names across the community.
• The manual lists external modules known to work: LAN8720 RMII Ethernet, PCM5102 I2S DAC, AN108/AN926 fast ADC/DAC (via gojimmypi adapter), e-ink 1.54” IL3829, ST7789 LCDs.

Open questions

• The manual’s “Board differences” section still calls v3.1.4/v3.1.6 “currently tested”. Check whether v3.1.7 is now the mainstream shipping revision (Mouser listing).
• The manual mentions a v18 LPF compatibility class, but no v1.8 LPF exists in the repo.
• doc/TODO.txt not yet read.