====== Instrument cluster (IP) ======

The **driver's dashboard** — the instrument panel behind the steering wheel — is its own **self-contained computer**, separate from the head unit. It is the module that shows speed, range, state-of-charge, drive mode and the warning lamps. Unlike the centre touchscreen, the head unit **cannot draw on the main cluster**: the cluster renders its own screen and only //reads// values that other modules broadcast on the CAN bus. See [[:architecture|Architecture]] for where it sits.

{{ :ip_cluster.png?900 |Instrument cluster — internal architecture }}

===== System =====

The cluster is a small **embedded Linux computer** paired with a safety microcontroller — the same "big SoC + guardian MCU" split used by the [[:hardware|head unit]] and the [[hardware:tbox|TBox]].

  * **SoC** — an **NXP i.MX6 (Dual)** application processor.
  * **OS** — a lightweight **Buildroot Linux** (kernel **4.1.15**) on **eMMC**, booted by **U-Boot**. Not Android.
  * **UI** — a custom ARM graphics application (vendor "xtd") that renders to the panel's framebuffers; all the gauges, lamps, drive-mode artwork and start-up animation are image assets shipped with it.
  * **Companion MCU** — a separate safety microcontroller carries the **legally-mandatory tell-tales**. This is deliberate: the warning lamps must keep working even if the Linux UI hangs, so the safety-critical layer does not depend on the application processor. Practically, the "fancy" graphics live on Linux; the mandatory warnings live on the MCU.

===== How it connects =====

The cluster is unusually **isolated** for a networked-looking device:

  * **No general network.** It has no Ethernet and no Wi-Fi of its own — there is no IP address to reach it on.
  * **Vehicle data** arrives over **CAN**, but the Linux side never touches the bus directly; its companion MCU does, and hands the values up. Same one-hop-from-CAN pattern as the other modules.
  * **Display link to the head unit** — the head unit feeds one of the cluster's panels over a **serialised video link (FPD-Link)**. Importantly this link is **bidirectional**: besides carrying video, its back-channel is what the head unit uses to deliver cluster **firmware updates** (below).

===== Firmware & updates =====

Cluster firmware reaches the module two ways, and **neither is over the internet directly** — the cluster has no network:

  * **Over-the-air (field):** the [[hardware:tbox|TBox]] pulls the update bundle over cellular, the **head unit** receives the cluster's part, and pushes it into the cluster over the **FPD-Link back-channel** as a simple framed, checksummed block transfer. A small updater service on the cluster receives it, verifies it, and installs both the Linux UI part and the companion-MCU part.
  * **Workshop:** the dealer diagnostic tool flashes it the standard way — **UDS over CAN** through the gateway, behind Security Access. See [[:obd2|OBD-II diagnostics]].

The update packages are **encrypted archives** that the cluster unpacks and self-installs at boot. The integrity check inside them is a plain checksum rather than a cryptographic signature.

===== Access surfaces =====

Because the cluster is a normal (if small) Linux box, it has the usual embedded-Linux entry points — a **serial console**, a **USB** interface used by the factory flashing tool, the **firmware-update channel** described above, and the **UDS** diagnostic path. Each has been examined and is understood well enough to characterise how the module boots, updates and could be serviced. Details are kept off this page.

<WRAP center round important 60%>
This is the **driver's instrument cluster** — it shows speed, range and safety-critical warning lamps. Anything done here is **own-vehicle only** and must be validated off-vehicle first; a bad image can leave the cluster with no working UI.
</WRAP>

===== Firmware versions seen =====

^ Part number ^ Region ^ Vehicle SW ^
| ''861921104C'' | EU | 1.3.0 |
| ''861821104B'' | CH | 1.3.0 |
| ''861921104B'' | CH | 1.6.1 |
| ''861921104D'' | CH | 1.7.1 / 1.7.2 |

//What's understood so far. To be continued.//