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HDMI Display

This guide explains how to connect a display to the board, configure it where needed, verify that it is detected, and render content on it.

The Grinn AstraADA-1680 routes the HDMI signals from the Grinn AstraSOM-1680 to the Astra Machina Foundation Series board, so the monitor is attached to the Machina board and driven through the adapter. The transmitter sources up to 4K60p video. No Device Tree Overlay or image extension is needed, because the interface is enabled in the default image.

Connect the Display​

The board exposes a HDMI Type-A connector (J12) on the Astra Machina Foundation Series board, so a cable or adapter that matches that connector on one end and the monitor on the other end is required.

  1. Plug the cable into the HDMI Type-A connector (J12) on the Astra Machina Foundation Series board.
  2. Connect the other end to the monitor and select the matching input source on it.
  3. Power on the board.
note

The interface is hot-pluggable, so the monitor can also be attached while the board is running. Connecting it before power-on is still recommended, because the compositor then picks up the monitor's preferred resolution on the first start.

Verify the Display​

On the host, enter the target shell:

adb shell

In the target shell, list the DRM connectors and their status:

for status in /sys/class/drm/card*-*/status; do
  connector=${status%/status}
  printf '%s: %s\n' "${connector##*/}" "$(cat "$status")"
done

The connector the display is attached to has to be reported as connected, for example:

card0-HDMI-A-1: connected

If the connector is missing or reported as disconnected, check the connection as described above.

Keep this target shell open for the examples below.

Use the Display​

The image runs a Wayland / Weston compositor by default, so the desktop appears on the display as soon as it is detected. The following steps run in the target shell.

Point the Wayland clients at the running compositor first:

WAYLAND_SOCKET=$(find /run/user -mindepth 2 -maxdepth 2 -type s -name 'wayland-*' -print -quit)

export XDG_RUNTIME_DIR="${WAYLAND_SOCKET%/*}"
export WAYLAND_DISPLAY="${WAYLAND_SOCKET##*/}"

Then render a test pattern full screen:

gst-launch-1.0 -v videotestsrc \
! video/x-raw,format=NV12 \
! waylandsink fullscreen=true

A color bar pattern covering the whole display confirms that the pipeline works end to end. Press Ctrl+C in the shell to stop it.

Use Both Displays at Once​

The board drives the MIPI DSI panel and the HDMI display as two independent outputs at the same time, and both of them can be configured to run Weston. Connect the second display as described in the MIPI DSI display guide.

With both attached, the verification command reports both connectors as connected:

card0-DSI-1: connected
card0-HDMI-A-1: connected
note

Mirroring the same output to both displays is not supported.