KOE LVDS Capacitive Display Set

This section shows information about the KOE LVDS Capacitive Display Set. The iMX8M Industrial Development Kit in this configuration is equipped with Yocto dunfell, kernel 5.4 to support LVDS display with a touchscreen layer. In this case the display is installed on the top of the iMX8M Development Baseboard.

Mechanical connection

When combined with the complete iMX8M Industrial Kit, the Display Set creates a compact, ready-to-use solution. To assemble them together, the following mechanical and electrical accessories were designed and selected to be part of the Display set:

TFT LCD 1920 x 1080 Pixels display (TX18D200VM0EAA) with LVDS interface and Capacitive Touch with SIS9509 controller
4x Hex Standoff Threaded M3 35.00mm long [Manufacturer PN: 971350321]
custom 20-pins LVDS cable, 180mm long. The cable is supply with LCD as set
custom 2-pins cable for LCD back light, 150mm long. The cable is supply with LCD as set
necessary spacers

Hardware connection

To enable smooth communication between the board and the display, connect the 20 Position LVDS cable for LCD and 6 pin touchscreen FFC cable. To implement the display capabilities, following connections need to be made:

connection between LVDS Display and iMX8M Development Baseboard connector LVDS0 KOE (J14) using a 20 Position LVDS cable
2 position back light cable connect to connector J15
touchscreen connection between iMX8M Development Baseboard connector KOE Touch (J40) and Touchscreen 6 pin FFC cable

LVDS and Touchscreen cable

Software instructions

iMX6 Rex Display Set is preinstalled with Android operation system enabling LVDS and touchscreen capabilities by default. Manual configuration is not necessary, but might be useful in individual cases.

LVDS manual booting

Manually booting with LVDS interface as a primary source for video output:

Rex U-Boot > setenv video 'video=mxcfb0:dev=ldb,edt570,if=RGB666 video=mxcfb1:off'
Rex U-Boot > boot

Touchscreen test

Make sure TSC2007 chip is detected and bound as input device:

root@imx6-rexultra:~# dmesg | grep -i tsc2007
input: TSC2007 Touchscreen as /devices/soc0/soc.0/2100000.aips-bus/21a4000.i2c/i2c-1/1-0048/input/input0
evbug: Connected device: input0 (TSC2007 Touchscreen at 1-0048/input0)

Touchscreen events are generated after pressing the resistive layer:

root@imx6-rexultra:~# evtest /dev/input/by-path/platform-21a4000.i2c-event 
Input driver version is 1.0.1
Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
Input device name: "TSC2007 Touchscreen"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 330 (BTN_TOUCH)
  Event type 3 (EV_ABS)
    Event code 0 (ABS_X)
      Value   3529
      Min        0
      Max     4095
    Event code 1 (ABS_Y)
      Value    375
      Min        0
      Max     4095
    Event code 24 (ABS_PRESSURE)
      Value      0
      Min        0
      Max     4095
Properties:
Testing ... (interrupt to exit)
Event: time 1457899907.959665, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1457899907.959665, type 3 (EV_ABS), code 0 (ABS_X), value 1657
Event: time 1457899907.959665, type 3 (EV_ABS), code 1 (ABS_Y), value 2486
Event: time 1457899907.959665, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 3268
Event: time 1457899907.959665, -------------- EV_SYN ------------
Event: time 1457899907.969094, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1457899907.969094, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 0
Event: time 1457899907.969094, -------------- EV_SYN ------------