Differences

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--- hardware:ip_board [2026/10/13 21:59] – external edit 127.0.0.1
+++ hardware:ip_board [2026/10/14 12:02] (current) – external edit 127.0.0.1
@@ Line 24: / Line 24: @@
 connectors.
-===== Photos =====
+===== Photos — front side =====
-==== U100 — NXP i.MX6 Dual (the processor) ====
+**U100 — NXP i.MX6 Dual (the processor)**\\
 {{ :ip_cluster:ip_u100_imx6.jpg?700 |U100 NXP i.MX6 Dual MCIMX6D6AVT08AD }}
-==== U500 — NXP MMPF0100 (power management) ====
+**U500 — NXP MMPF0100 (power management)**\\
 {{ :ip_cluster:ip_u500_pmic_pf0100.jpg?700 |U500 NXP MMPF0100 PMIC }}
-==== U300 — ISSI DDR3 memory ====
+**U300 — ISSI DDR3 memory**\\
 {{ :ip_cluster:ip_u300_ddr3_issi.jpg?700 |U300 ISSI IS46TR16128C DDR3 }}
-==== U401 — TI DS90UB940A (FPD-Link III: reverse-camera + head-unit back-channel) ====
+**U401 — TI DS90UB940A (FPD-Link III: reverse-camera + head-unit back-channel)**\\
 {{ :ip_cluster:ip_u401_fpdlink940.jpg?700 |U401 TI DS90UB940A FPD-Link III deserializer }}
-==== U900 / U902 — TI DS90CF386 (LVDS display receivers) ====
+**U900 / U902 — TI DS90CF386 (LVDS display receivers)**\\
 {{ :ip_cluster:ip_u900_lvds386.jpg?700 |U900 TI DS90CF386 LVDS receiver }}
 {{ :ip_cluster:ip_u902_lvds386.jpg?700 |U902 TI DS90CF386 LVDS receiver }}
-==== U804 — NXP TJA1044 (CAN transceiver) ====
+**U804 — NXP TJA1044 (CAN transceiver)**\\
 {{ :ip_cluster:ip_u804_can_tja1044.jpg?700 |U804 NXP TJA1044 CAN transceiver + B82793 chokes }}
+===== The other side of the board =====
+The reverse of the PCB carries the **companion microcontroller** and the cluster's audio and
+power-supervision support. The board-ID sticker reads **型号 (model) 861921104E** and
+**名 (name) S22060123-1** — a hardware-revision **E** (the EU track), matching the ``861921104E``
+part number the cluster reports over UDS.
+{{ :ip_cluster:ip_back_overview.jpg?900 |Instrument cluster board — reverse side }}
+^ Ref ^ Part ^ What it is / does ^
+| **U800** | **NXP / Freescale ``S912XHY256VLM``** (MC9S12XHY256) | The **companion 16-bit "safety" microcontroller** — an S12X automotive part made specifically for instrument clusters: on-chip CAN + LIN, stepper-motor control with stall detection, and LCD drive; 256 KB flash, 12 KB RAM, 8 KB EEPROM, 100-pin LQFP. It is the node actually on the **vehicle CAN bus**, and it guarantees the mandatory warning lamps independently of the Linux side. This is the chip that runs the ``mas861.s19`` MCU firmware. |
+| **U301** | **ISSI ``IS46TR16128C``** DDR3 SDRAM | The **second** DDR3 device of the i.MX6's memory pair (its twin **U300** is on the front) — mounted on the back under the processor to complete the 32-bit bus. |
+| **U700** | **ROHM ``BD4275FP2``** | Automotive **5 V / 0.5 A LDO regulator with a built-in reset / voltage-detector** (TO-263-5F). Supplies and supervises the microcontroller rail — it holds the MCU in reset until the rail is good (reset threshold ~4.6 V). |
+| **U803** | **Nuvoton ``ISD2360SYI``** ChipCorder | A **voice record / playback IC** (SPI, up to 64 s of audio, 16-SOIC). This is the cluster's **chime / warning-sound** store-and-play engine — the source for the buzzer. |
+| **U903** | **MPS ``MPSM24`` / ``M3387L``** (24-pin QFN) | A Monolithic Power Systems device next to the audio section — most likely the **amplifier** that drives the chime speaker from the ISD2360 //(identification tentative)//. |
+| **U801** | **Microchip / Atmel ``AT24`` I²C EEPROM** (``ATMLH119 04CM``) | A small serial EEPROM for configuration / calibration data. |
+Also on this side: the input-protection diodes **D701** / **D703**, a switching-supply module
+(**TUS700**, top-left) and the bulk of the board's decoupling.
+**U800 — NXP/Freescale S912XHY256 (the companion safety MCU)**\\
+{{ :ip_cluster:ip_u800_s12xhy.jpg?700 |U800 Freescale S912XHY256VLM — cluster MCU }}
+**U700 — ROHM BD4275FP2 (5 V LDO + reset supervisor)**\\
+{{ :ip_cluster:ip_u700_bd4275.jpg?700 |U700 ROHM BD4275FP2 regulator }}
+**U803 — Nuvoton ISD2360 (chime / warning-sound playback)**\\
+{{ :ip_cluster:ip_u803_isd2360.jpg?700 |U803 Nuvoton ISD2360SYI ChipCorder }}
+**U903 — MPS audio amplifier (chime speaker)**\\
+{{ :ip_cluster:ip_u903_amp.jpg?700 |U903 MPS MPSM24 / M3387L }}
+**U301 — ISSI DDR3 (second device)**\\
+{{ :ip_cluster:ip_u301_ddr3b.jpg?700 |U301 ISSI IS46TR16128C DDR3 }}
+**U801 — Atmel AT24 I²C EEPROM**\\
+{{ :ip_cluster:ip_u801_eeprom.jpg?700 |U801 Atmel AT24 EEPROM }}
+**Power input (D703 / TUS700 region)**\\
+{{ :ip_cluster:ip_back_power_d703.jpg?700 |Reverse-side power-input section }}
+//Chip markings read directly from the dies; U800 confirmed against NXP's ``S912XHY256`` product
+listing. Date / lot codes: U800 lot ``QNH2202C``, U803 date ``2142`` (2021 wk 42), U301 ``IS46TR16128C-125KBLA1``.//
 ===== How it all connects =====
-  * Vehicle CAN → **TJA1044** (U804) → **i.MX6** (U100): the cluster //reads// speed, gear, state-of-charge and the lamp requests off the bus and renders them. It cannot be driven by the head unit directly.
+  * Vehicle CAN → **TJA1044** (U804) → the **S12 microcontroller** (U800, ``S912XHY256``): the MCU is the only node on the bus. It reads speed, gear, state-of-charge and the lamp requests, drives the mandatory warning lamps itself, and passes the rest to the i.MX6 over a private SPI link. The cluster cannot be driven by the head unit directly.
-  * **i.MX6** → LVDS → **DS90CF386** (U900/U902) → the two dashboard LCD panels.
+  * **i.MX6** (U100) → LVDS → **DS90CF386** (U900/U902) → the two dashboard LCD panels (it draws all the gauges and artwork).
   * Head unit → coax (FPD-Link III) → **DS90UB940A** (U401): the **reverse-camera** image, plus the data/firmware back-channel. (The right "media" strip itself is drawn locally by the i.MX6, not fed from here.)
-  * **MMPF0100** (U500) powers the i.MX6; the **S12 MCU** independently holds the safety tell-tales.
+  * **MMPF0100** (U500) powers the i.MX6; **BD4275FP2** (U700) supplies and supervises the **S12 MCU** rail, which independently holds the safety tell-tales.
+  * Warning sounds: **ISD2360** (U803) stores and plays the chimes → audio amp (U903) → the **UGSP3708** buzzer on the front.
 //Photos and identification from a bench teardown of a spare unit. Chip markings read directly from the
-dies; the S12 MCU is identified from the firmware, not pinpointed in these photos.//
+dies. The companion safety MCU — previously known only from the firmware — is now pinpointed as
+**U800** on the reverse side (NXP/Freescale ``S912XHY256VLM``).//