Role: Host for the SIL-2 / SIL-0 onboard crates —
osr-ato, osr-tcms,
osr-dmi, osr-pis-onboard,
osr-hvac, osr-lighting,
osr-aux-power,
osr-event-recorder,
osr-regen, osr-hot-axle,
osr-cbm-onboard,
osr-t2g, osr-tcn.
Canonical light-metro-3car fit: 2 boards per trainset, one in
the A-end electronics cabinet and one in the B-end electronics
cabinet. T-ECU/A is single-redundant and non-safety; the T-ECU/S +
T-OBS safety chain continues without it.
Environment: EN 50155 OT4, single-redundant.
Raspberry Pi CM5 (BCM2712, Cortex-A76 4-core, 4–16 GB LPDDR4X, eMMC on-module) on a custom baseboard. Radxa CM5 (RK3588S) is the pin-compatible drop-in via the same SO-DIMM footprint — only the device-tree blob changes. Operators may source whichever module is locally stocked.
See RFC 0007 §5.
| Peripheral | Qty | Purpose |
|---|---|---|
| TSN Ethernet | 2 | TCN-E A/B |
| CAN-FD | 2 | HVAC + lighting |
| USB-C host+device | 2 | Depot console + diag loader |
| HDMI | 1 | DMI touchscreen |
| USB 2.0 | 2 | DMI touch, PIS display |
| M.2 2280 NVMe | 1 | Event recorder + OTA staging |
| M.2 2230 Cat.22 5G | 1 | TRG-1 primary radio |
| LoRa SX1276 on SPI | 1 | TRG-2 backup radio |
| SPI bridge to T-ECU/S | 1 | One-way feed from the safety board |
| ATECC608B SE | 1 | Trust anchor |
160 × 100 mm Eurocard (same DIN slot as T-ECU/S). Heatsink → enclosure conduction cooling, no fans.
~€220 per board (CM5 ≈ €85, baseboard ≈ €75, radios ≈ €60).
The consist-level procurement quantity is tracked in
../rolling-stock-integration.md
and line E2 of the rolling-stock BOM.
- Pilot / DIY track:
diy-assembly/uses a stock RPi CM5 IO Board + Waveshare M.2 HAT + generic Cat.22 5G M.2 module to validate peripheral enumeration before any custom baseboard is drawn. Integration evidence is still pending. - Custom-board track:
schematics/v2-spec/is the board-level v2 specification overview and block diagram.gerbers/andbom/remain pending until a KiCad layout and board BOM are released.