Android Dual Screen Support

This application note contains steps to enable dual screen with Android in mirror mode or extended mode.

The following panel is currently supported with the AM625 SK EVM revision E3 board:

  • Microtips Technology USA (13-101HIEB0HF0-S) 10.1” WUXGA (1920x1200) TFT LCD panel

The following panels are currently supported with the AM62P SK EVM board:

  • Microtips Technology USA (13-101HIEB0HF0-S) 10.1” WUXGA (1920x1200) TFT LCD panel

  • Raspberry Pi Touch 7” Display

Note

By default Android configures the displays in mirror mode.

Warning

On recent Android 15 versions, we suspect there is a known issue at the framework level. After booting with both displays plugged, the external (HDMI) display is blank. To fix this, use the following sequence:

  • Boot with both HDMI and DSI display plugged in

  • Wait for launcher to appear. We will see notification for external display

  • Click to mirror: we will see nothing on the mirrored screen

  • Unplug HDMI

  • Re-plug HDMI. it now works in mirror mode.

How to enable an additional panel on the EVM

Steps to enable touch on the Microtips Panel on AM625 SK EVM:

Note: The following steps are only applicable on AM625 SK EVM revision E3 board.

  1. Power off the LVDS board by disconnecting the 12V barrel jack (do not power off the SK EVM)

  2. Run the following commands from the Linux prompt:

    console:/ $ su
console:/ # rmmod ili210x
console:/ # i2ctransfer -f -y 0 w3@0x3f 0x09 0x1 0x0e
console:/ # i2ctransfer -f -y 0 w6@0x3f 0x08 0x04 0x47 0x50 0x73 0x68

  3. Power on the LVDS board

  4. Run the following command:

    console:/ # insmod /vendor/lib/modules/ili210x.ko

After re-initializing the module, the touch IC should now be registered as an input and touch should be functional.

Attention

This step need to be done each time the board reboots.

How to enable Extended Display in Android

By default, Android configures the external display in mirroring mode. In order to start activities on the external display, we should use another launcher, named MultiDisplay. The code for this launcher is available in development/samples/MultiDisplay.

For more information about multi display in Android, refer to the AOSP documentation.

To enable MultiDisplay:

  1. Follow the Fetching the code guide.

  2. Edit device.mk file to add this:

    PRODUCT_PACKAGES += MultiDisplay

  3. Rebuild Android following the Build guide.

  4. Reflash Android images following Flashing instructions guide.

  5. After booting is complete, select MultiDisplay as default launcher via the touchscreen.