This guide walks through the basic usage of an OLDI display used in conjunction with the phyCORE-AM57x development kit.

Requirements 

ItemItem Number (Description)Link

7" LVDS Capacitive Touch Display 

LCD-018-070-KAP

Capacitive Touch Display 

Setting up the Display

There is a switch labeled "S1" on the back of LCD-018 where the backlight can be set to either: "always on", "always off", "PWM", or "potentiometer" (there is a point on the display with reference designator R30). In order to control the backlight via the phyCORE-AM57x as described in this guide, the boot switch needs to be set to PWM. (1,2,4 OFF; 3 ON)

  • With the kit powered off and the power supply removed, connect the display to connector X25 on the phyCORE-AM57x Carrier Board as shown in the picture below.

  • Power on the board and boot into Linux. 
  • An application called the Matrix-GUI will appear on the display.

Controlling the Backlight

The backlight brightness of the display is controlled by a PWM and can be configured via Linux in the sysfs. 

  • To read the current backlight brightness:

    Target (Linux)

    cat /sys/devices/platform/backlight/backlight/backlight/brightness
    CODE
  • Set "brightness" to values 0-7, with 7 being the brightest. For example:

    Target (Linux)

    echo 7 > /sys/devices/platform/backlight/backlight/backlight/brightness
    CODE
  • Set bl_power to turn backlight off/on. Valid values are 1 for off and 0 for on:

    Target (Linux)

    echo 1 > /sys/devices/platform/backlight/backlight/backlight/bl_power
    echo 0 > /sys/devices/platform/backlight/backlight/backlight/bl_power
    CODE

    Not seeing the display brightness change? Check the above Note!

Calibrating the Touch Controller

If you find that your touches on the display are not registering correctly then it is likely you need to re-calibrate the touch controller. See the below steps for instructions on how to do this!

  • Enter the following command: 

    Target (Linux)

    weston-calibrator
    CODE
  • On the display you should see a white background with a red X somewhere on the screen. Tap the red X's as they appear until complete.

GStreamer Encoder/Decoders

The phyCORE-AM57x Linux BSP comes equipped with video encoding/decoding capabilities using GStreamer Pipelines and also includes sample files for exploring these capabilities. 

  • In order to validate your kit's video encoding capabilities, first stop all graphics processes: 

    Target (Linux)

    /etc/init.d/matrix-gui-2.0 stop
    /etc/init.d/weston stop
    CODE

    You should now see a black screen that displays the text "Please wait..."

  • Execute the following command to encode a raw video into MPEG format: 

    Target (Linux)

    gst-launch-1.0 filesrc location=/usr/share/ti/video/airshow_p352x288.yuv ! videoparse width=352 height=288 format=nv12 ! video/x-raw, width=352, height=288 ! ducatimpeg4enc ! filesink location=/home/root/airshow_p352x288.mp4
    CODE
  • Now decode the MPEG video that was just generated: 

    Target (Linux)

    gst-play-1.0 /home/root/airshow_p352x288.mp4
    CODE

    You should see a short clip play on the display.

Other encoder/decoder demos are also available:

H.265 (HEVC) Decode

Target (Linux)

gst-launch-1.0 filesrc location=/usr/share/ti/video/TearOfSteel-Short-1280x720.265 ! 'video/x-raw, format=(string)NV12, framerate=(fraction)24/1, width=(int)1280, height=(int)720' ! h265dec threads=2 ! vpe ! kmssink
CODE

H.264 (IVAHD) Encode

Target (Linux)

gst-launch-1.0 filesrc location=/usr/share/ti/video/airshow_p352x288.yuv ! videoparse width=352 height=288 format=nv12 ! video/x-raw, width=352, height=288 ! ducatih264enc ! filesink location=/home/root/airshow-352-288-nv12-inp_gst.h264
CODE

H.264 (IVAHD) Decode

Target (Linux)

gst-launch-1.0 filesrc location=/home/root/airshow-352-288-nv12-inp_gst.h264 ! queue ! h264parse ! ducatih264dec ! kmssink
CODE