[HuggeK]

What does this PR do?

Redraws the OPS243 GPIO-UART wiring for the case layout, splits the header documentation into three diagrams, and adds a diagram for the IWR6843 boot switch.

• docs/assets/ops243-uart-wiring.svg, redrawn the way the parts sit in the case (OPS243 upside down with J3 pins up, Pi rotated with USB ports up):
  • OPS243: 5V J3-9 → Pi 4, GND J3-10 → Pi 6, crossed UART (J3-7 → Pi 10, J3-6 → Pi 8).
  • SEN-14262 sound trigger: VCC → Pi 1 (3.3V), GND → Pi 9, GATE spliced three ways to J3 pin 3 (HOST_INT) and Pi 11 (GPIO17).
  • Ribbon connectors labelled on the Pi for orientation: CAM/DISP 1, nearer the USB ports, takes the camera (dtoverlay=ov9281,cam1); CAM/DISP 0, below it, takes the Touch Display 2.
• Header docs as two separate diagrams, each showing one thing:
  • docs/assets/pi5-gpio-header-map.svg: the Pi 5 40-pin header (OPS243, SEN-14262, LIS3DH, display power, Geekworm X1202 pogo pins).
  • docs/assets/ops243-j3-header.svg: the OPS243-A J3 header seen from the front, and which pins are wired.
• docs/build/ops243-uart.md: links the diagrams; the J3 table now shows pin 3's GATE splice to Pi 11; the caption says any 5V/GND pin works as long as all boards share one ground, and gives the camera's config.txt line.
• New docs/assets/iwr6843-s1-boot-switch.svg: the IWR6843LEVM S1 DIP switch as it faces you on the mounted board, upside-down markings included, with the flashing and functional settings. Only S1.1 changes. Shown in step 2 of docs/iwr6843/flashing.md and referenced from step 5. A photo of the switch on a mounted board (docs/assets/iwr6843-s1-boot-switch-photo.jpg, metadata stripped) sits under it.

Why was this required?

The existing UART diagram is drawn for a different board orientation than the case, which makes it hard to follow when wiring inside the enclosure. There was also no single map of every header pin and connector used in the full build (OPS243, sound trigger, LIS3DH, display, UPS, camera). The IWR flashing guide gives the S1 settings only as text, and the switch's printed markings read upside down on the mounted board, which makes S1.1 easy to misidentify.

SEN-14262 ground pin

The original diagram grounds the sound detector on Pi pin 6. In this case layout pin 6 carries the OPS243 ground and pin 14 the display ground, so the drawing uses pin 9. Any ground pin works, since all boards share one ground rail, and the caption says so.

Ribbon connectors: checked on the hardware

On the Pi 5 the Touch Display 2 runs on CAM/DISP 0, the lower connector: display_auto_detect loads vc4-kms-dsi-ili9881-7inch on dsi@110000, the same RP1 MIPI block ov9281,cam0 uses. With the camera configured as cam0 it failed (ov9282 10-0060: fail to write MIPI_CTRL00, rp1-cfe … -EBUSY). With dtoverlay=ov9281,cam1 (camera on CAM/DISP 1, the connector nearer the USB ports) it enumerates on i2c@80000 and rpicam-hello --list-cameras lists it. The wiring diagram labels both connectors on the Pi accordingly.

Automated tests

Documentation and SVG only, so there's nothing executable to test. All SVGs parse as XML, and the docs build (docs.yml) covers rendering and links.

Manual (human) testing

• Each SVG was rendered in a browser and checked by eye, including a zoomed check that every wire lands on the right header pin (pins 1, 4, 6, 8, 9, 10, 11). Each has a <title>/<desc> and matching alt text in the Markdown.
• The S1 boot switch diagram was used for a real flash of openflight_iwr6843_v1.0.3.bin: flashing mode and back to functional mode, S1.1 only.
• The OPS243 UART pins, display and camera connectors were checked on the real build (OPS243 on /dev/ttyAMA0, rpicam-hello, dmesg, device tree).

Scope note

This bundles two related doc changes, the OPS243/header wiring and the IWR6843 S1 switch diagram, because both came from the same build write-up. Happy to split them into separate PRs if preferred.

Checklist

• Single feature/fix: two related doc changes (see scope note)
• Automated tests included: n/a, docs and SVG only
• Manual testing described: I documented what was verified by hand above
• Python tests pass: no code changes
• Pylint passes: no code changes
• Ruff passes: no code changes
• UI builds: no ui/ changes
• UI lint passes: no ui/ changes
• Updated docs or CHANGELOG if needed
• No unrelated changes mixed in

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