I am using COG-C144MVGI. I am trying to turn it on with my Raspberry Pi.

I am not sure if I am following the "power on sequence" correctly. Does this kind of LCD modules work without backlight? I am wondering if I am supposed to get some kind of reaction on the screen even without backlight. Thank you.

Here is the datasheet :


  • 1
    \$\begingroup\$ It is a transmissive type so yes it needs a backlight for good visibility. \$\endgroup\$ Aug 15, 2018 at 17:03
  • \$\begingroup\$ @TonyEErocketscientist Thank you. So I would be able to see the pixels even without the back light but not as much as visible as when the backlight is on. \$\endgroup\$
    – user167987
    Aug 15, 2018 at 17:40
  • \$\begingroup\$ A front flash light reflected of the back can check that it works but not nearly the contrast \$\endgroup\$ Aug 15, 2018 at 17:43
  • \$\begingroup\$ @TonyEErocketscientist Thank you. This at least gives me what I am doing correctly and what not. A huge progress. \$\endgroup\$
    – user167987
    Aug 15, 2018 at 17:47

1 Answer 1


Probably you will see information on the display when the backlight is off, but not when it is dark (or not so light). (Also, there exist LCD displays without backlight).

However, a reason to switch backlight off, is to preserve current (especially useful in a battery operated system).

Page 6/7 show information about LED A/LED K how to control the backlight.

  • \$\begingroup\$ I had no problem with the backlight. I am just having a trouble correctly execute the power on sequence :) Thank you. \$\endgroup\$
    – user167987
    Aug 15, 2018 at 17:38

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