Simplest possible PicoSoC implementation using wafer.space flow
PSOC · RISC-V and CPUs · 1 × ½ slot
Rendered from the layout at 2.5 µm per pixel. Layers: NwellDiffusionPolysiliconMetal 1Metal 2Metal 3Metal 4Metal 5Top metalPad openings
Logic density
| Inside the core logic cells per mm² | 4k
(5% of buffer maximum) over the 5.02 mm² core: what the design itself packed |
|---|---|
| Inside the seal ring logic cells per mm² | 2k
over all 9.61 mm² of the slot, pad ring included |
| Core covered by logic | 11% |
| Transistor density transistors per mm² | 210k average |
Every figure here is measured from the public layout, the same way for every design on the run: see data and method, and how its designs used the process.
Established as a FOSS flow proof of concept for SoC design. Eventually we hope to add wishbone bus and peripherals, open-drain IO for I2C and I2C controller, bandgap reference and voltage regulators, etc.
| Die | 3.93 × 2.53 mm (9.9 mm²) |
|---|---|
| Core area | 5.02 mm² inside the pad ring
as set in the design's own layout settings |
| Inside the seal ring | 9.61 mm² (the die less its 26 µm seal ring) |
| Placements | 1 on the reticle, in slot D2 |
| Bond pads | 72 |
| Transistors | 1,052,766 |
| Logic cells | 18,372 + 86,401 filler and tap cells |
| Libraries | 7t-5V (18k) |
| SRAM | 8 macros, 32,768 bits |
Submission
| Licence | Apache-2.0 declared
Repository: Apache-2.0 in LICENSE — agrees |
|---|---|
| Template | wafer-space/gf180mcu-project-template 1.5.5 or 1.5.6 |
| How it was checked | Commit and PDK pinThe licence and template were read from the repository at commit a5283bc607b0.The template releases named above are the ones whose Makefile pins the same PDK as that commit (PDK_COMMIT 140b0494c666). |
| Chip-on-board | Not selected at submission |
| Precheck | Passed
the check it was accepted on, 2026-07-13, gf180mcu-precheck 1.7.1 (from its image)
Passed latest re-run, 2026-08-03, gf180mcu-precheck 1.7.3 step results and logs |
Process features
Which parts of the GF180MCU process this design uses: its transistor voltages and where they come from, its gate oxides, and any devices drawn by hand outside the standard cells, SRAM and pads.
| 5 V | 7t-5V standard cells, fd SRAM |
|---|---|
| Gate oxides | Thick only (5 V/6 V) in the design itself |
| I/O library | gf180mcu_fd_io (758 cells) |
Where the area went
How this design's area splits between logic cells, SRAM, filler and tap cells, other and pad ring.
- Logic cells 0.57 mm² (6%)
- SRAM 1.68 mm² (17%)
- Filler and tap cells 2.60 mm² (26%)
- Other 0.18 mm² (2%)
- Pad ring 4.92 mm² (50%)
Most used cells
The ten standard cells this design uses most.
| Cell | Library | Instances | What it does |
|---|---|---|---|
| dlyb_1 | 7t-5V | 3,895 | Delay buffer |
| nand2_1 | 7t-5V | 2,274 | 2-input NAND gate |
| dffq_1 | 7t-5V | 1,871 | D flip-flop (1 bit storage) |
| oai21_1 | 7t-5V | 1,851 | OR-AND-Invert compound gate |
| dlyc_1 | 7t-5V | 1,108 | Delay buffer |
| buf_4 | 7t-5V | 817 | Buffer (4x drive) |
| nor2_1 | 7t-5V | 814 | 2-input NOR gate |
| clkinv_1 | 7t-5V | 533 | Clock inverter |
| mux4_1 | 7t-5V | 531 | 4-input multiplexer |
| buf_2 | 7t-5V | 509 | Buffer (2x drive) |
Logic density map
Logic cells per mm² in each square millimetre of the die. Hatched outlines are SRAM macros; the red outline is the densest mm² that avoids them (4k logic cells per mm²), found by sliding a 1 mm square over the die in 0.1 mm steps, so it can straddle the fixed squares and find more than any one of them. Squares at the edges are partial, so they read low.
SRAM macros
The ready-made memory blocks this design uses.
| Macro | Count | Bits each |
|---|---|---|
| gf180mcu_fd_ip_sram__sram512x8m8wm1 | 8 | 4,096 |
Precheck
Before a design is made, the wafer.space platform checks it against the foundry's design rules. PSOC was accepted on this check, and has been checked again since with newer rules.
All 16 steps passed, with 0 KLayout DRC errors, on 2026-07-13.
Every step, and the latest re-run
| Step | Accepted on check 478, 2026-07-13, initial, gf180mcu-precheck 1.7.1 (from its image) PDK open_pdks 1.0.604, LibreLane 5fe3db1 | Latest re-run check 775, 2026-08-03, drc_update, gf180mcu-precheck 1.7.3 PDK open_pdks 1.0.604, LibreLane 5fe3db1 |
|---|---|---|
| KLayout.ReadLayout | passed | passed |
| KLayout.CheckTopLevel | passed | passed |
| KLayout.CheckSize | passed | passed |
| KLayout.GenerateID | passed | passed |
| KLayout.Render | passed | passed |
| KLayout.Density | passed | passed |
| Checker.KLayoutDensity | passed | passed |
| KLayout.ZeroAreaPolygons | passed | passed |
| Checker.KLayoutZeroAreaPolygons | passed | passed |
| KLayout.Antenna | passed | passed |
| Checker.KLayoutAntenna | passed | passed |
| Magic.DRC | passed | passed |
| Checker.MagicDRC | passed | passed |
| KLayout.DRC | passed | passed |
| Checker.KLayoutDRC | passed | passed |
| KLayout.WriteLayout | passed | passed |
| KLayout DRC errors | 0 | 0 |
| Magic DRC errors (advisory) | 0 | 0 |
| Files | steps · log (gzip) | steps · log (gzip) |
The steps of the gf180mcu-precheck LibreLane flow, as run by platform.wafer.space. The design was accepted on the newest finished check before it was submitted; later re-runs check the same file with updated rules. KLayout DRC is the sign-off check. Magic DRC is advisory: its count does not stop a design. In the logs, Magic's "Error while reading cell" lines about fill cells are messages from its reader, not check failures.