The Aiways U5 consists of some Microcontrollers and Computers, wired together over a CAN bus. Knowing which box talks to which — and over what link — is the key to everything else.

A few links (the OBD gateway, exactly which ECUs sit on which bus segment) are still being confirmed.

• Head unit (infotainment) — a Freescale i.MX6 running Android 4.4.2, paired with a Renesas RL78 MCU. The SoC runs the UI; the MCU is the gatekeeper to the vehicle. They talk over a serial UART. This is the computer these pages mostly work on — see Hardware & OS.
• TBox (telematics) — the always-on cellular gateway: a Quectel AG35 LTE modem plus an NXP S32K144 MCU. It reaches the head unit over USB/IP, taps the CAN bus, and used to phone home over cellular — see TBox teardown and Connectivity.
• Vehicle CAN bus — the shared nervous system. The real ECUs live here: VCU (vehicle control), BMS (the HV battery), BCM (body), HVAC, TPMS, and more.
• Displays — four panels, but only two are driven by the head unit: the centre touchscreen (LVDS) and the right driver panel (HDMI). The main instrument cluster and left panel are a separate ECU that reads the CAN bus directly — the head unit cannot draw on them. See Cluster display.
• OBD-II port — sits behind a diagnostic gateway, isolated from the live internal bus.

Everything the head unit knows about the car arrives the same way — a value is broadcast on the CAN bus, picked up by the RL78 MCU, and passed over UART to Android, where an app reads it. State-of-Charge, for example: BMS → CAN → MCU → UART → Android → MQTT (see CAN bus and the signal reference).

Commands travel the other way — Android → MCU → CAN — which is how, for instance, the A/C is switched on (see Vehicle control).