If I only connect the VSS (pin 1) to ground and VDD (pin 2) to voltage, will I see anything on this LCD screen (as a test)?

Might I expect to see a cursor of some type?

pin out diagram

Simple data sheet: http://www.mouser.com/ds/2/178/08216h3-11837.pdf

Or do I have to send data also? I apply 5v (up to 6v) and I don't see anything.

Also, what is Vl pin 3?
Does it need voltage on it also?


Is there any easy way to test an LCD screen like this in lieu of connecting all data lines to a source?

EDIT 2 - success

All the great help got me there. Thanks to @Janka and @duskwuff. Janka, just like you said one dark row and one light row. DuskWuff - got the pot connected to Vl and adjusting that is what made it show up.

lcd with power and contrast

  • \$\begingroup\$ Seems like 8080 type interface, you would probably see a black screen. \$\endgroup\$ – user3528438 Oct 27 '17 at 18:42
  • \$\begingroup\$ Would the screen flash to black as each block in the grid is "lit"? I don't seem to see anything happen, wondering if it works before I connect all the lines for writing data to it. \$\endgroup\$ – raddevus Oct 27 '17 at 18:45
  • \$\begingroup\$ well I will leave that chicken-egg problem to you \$\endgroup\$ – user3528438 Oct 27 '17 at 18:46
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    \$\begingroup\$ The LCD will show one dark row and one light row, if the contrast is high enough. \$\endgroup\$ – Janka Oct 27 '17 at 18:50
  • 1
    \$\begingroup\$ Yes, exactly. Vss, Vdd and VL. Technically, you get most contrast for negative input voltages at VL for such displays. \$\endgroup\$ – Janka Oct 27 '17 at 18:55

What you have here is a HD44780-type character display. Displays of this type will typically display black blocks on the first line of the display when powered on.

It's technically possible to send commands to the display with a bank of switches, but it's annoying enough that I'd advise you to do it with a microcontroller. If you have an Arduino board handy, the LiquidCrystal library is an easy way to do this.

The VL input is a contrast control. Connect it to a potentiometer between VSS and VDD, and adjust it until the blocks are clearly visible.

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The LCD panel is based on the HD44780 controller. Providing the controller resets properly when you apply power you will see nothing on the screen. The Reset circuit (page 23 in the datasheet) initializes the controller ...it will be initialized much faster than you could see any data on the LCD.

enter image description here

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  • \$\begingroup\$ Thanks that makes things quite a bit more clear about what is going on. \$\endgroup\$ – raddevus Oct 27 '17 at 18:59

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