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Bring-up & Setup Guide

End-to-end procedure to go from boards in a box to a working obstacle sensor on your host. The board ships pre-flashed by Ascend with your chosen firmware variant — there's nothing to build or flash.

0. What you need

  • Ascend main board + up to 8 TOF sub-boards.
  • 8× 5-pin sensor cables (main-board sensor ports → TOF sub-boards).
  • A regulated 5 V supply on J1, or a USB-C cable (see Power).
  • A USB-UART adapter (921 600-capable) for the bench check, wired to J7 — default (sensor-stream) firmware only.
  • For flight integration: any host with a UART (flight controller or onboard computer). This guide uses a VOXL2 as the worked example; see Integration (any host) for other platforms.

1. Assemble & connect

  1. Plug each TOF sub-board into a main-board sensor port with a 5-pin cable. Note the channel ↔ port map — it determines each sensor's bearing in software:
Channel Port Channel Port
0 J6 4 J12
1 J5 5 J13
2 J4 6 J10
3 J3 7 J11
  1. Seat every cable fully before powering — see the connector pinouts in Hardware.

2. Power & bench-verify

(Default sensor-stream firmware — skip to step 3 if your board runs the ACO firmware, which talks to a flight controller rather than a terminal.)

  1. Connect the USB-UART adapter to J7 (board TX → adapter RX, GND↔GND), host set to 921 600-8N1.
  2. Power the board (5 V on J1, or USB-C).
  3. Open the port in any serial terminal: 
    screen /dev/tty.usbserial-XXXX 921600     # or minicom -D /dev/ttyUSB0 -b 921600
  4. You should see repeating --- CHn --- blocks, each followed by an 8×8 grid of millimetre distances — one per connected sensor, updating continuously.

Sanity checks - Wave your hand ~30 cm in front of one sensor → that channel's grid should drop to ~300 mm values. 0 = no return / invalid, not "obstacle at 0". - A missing channel → check that sensor's cable and connector seating.

3. Integrate with your host

Any host that can read the UART works. For a generic recipe (ArduPilot / PX4, ROS, bare MCU, …) see Integration (any host). The steps below are the VOXL2 worked example (default firmware).

  1. Wire the board's J7 UART to a VOXL2 high-speed UART (e.g. /dev/ttyHS1) and power the board.
  2. Install the Ascend-provided service: 
    dpkg -i voxl-ascend-8tof_<ver>_arm64.deb
systemctl enable --now voxl-ascend-8tof
  3. Configure /etc/modalai/voxl-ascend-8tof.conf — confirm uart_path matches the port you wired and uart_baud = 921600 (see Integration → Configuration).
  4. Wire into voxl-mapper — add the tof_pipe_* / depth_pipe_* slots and matching extrinsics.conf entries from Integration. Mount the board with CH3 facing the nose to match the extrinsics table.
  5. Validate placement — with voxl-mapper running, block one sensor at a time and confirm the obstacle shows up in the expected body direction in voxl-portal. Adjust that channel's mounting rotation if it lands wrong.

ACO firmware: instead of the above, wire J7 to a flight-controller TELEM port and enable the autopilot's obstacle-avoidance feature — see ACO Firmware.

Troubleshooting quick-reference

Symptom Likely cause / fix
No UART text at all Wrong baud — use 921 600-8N1; confirm board TX → adapter RX (not TX→TX).
Garbled text Baud mismatch — set 921 600.
A channel never appears Bad/loose sensor cable or connector.
invalid metadata, magic number=… in voxl-mapper chN_format doesn't match the slot type (tof2 → tof_pipe, point_cloud → depth_pipe).
Obstacle appears in wrong direction Wrong per-channel mounting rotation, or board not mounted CH3-forward.
Rear/side sensors ignored Using an old single-merged-cloud config — use per-pipe publishing.