CFAG12864B-TMI-V Power Questions

[schipper]

I just started hooking up the LCD and noticed some problems. I have pin 1 to 5V and 2 to ground. I then hooked up 8.5 to pin three for the LCD power. Nothing comes up and my 5V power supply pulls up to about 7.5V and the 8.5V source drops to 7.5V. I think also noticed that the LCD comes on with only pins one and two hooked up. Am I doing something wrong? Also, from reading on the side the last two pins are used for the LED backlight correct? Thank you for the help!

Preston

Crystalfontz LCD Blog

Looking for additional LCD resources? Check out our LCD blog for the latest developments in LCD technology.

 

[CF Tech]

Pin 1 is Vdd.
Pin 3 is Vo.

Vo is not Vlcd

Vlcd = Vdd - Vo

so:

Vo = Vdd - Vlcd

Vo = 5v - 8.5v = -3.5v

Your module has a "negative voltage generator", which will put -5v out on pin 18.

Typically you would connect a 10K pot between Vdd (Pin 1 = +5v) and Vee (Pin 18 = -5v) and then connect the wiper of the pot to Vo (Pin 3, adjust to -3.5v).

Hopefully the LCD is not cooked. If it is you can write us and we will come up with some kind of a solution.