# Will HD44780 display be hurt with 20mA on contrast pin? (pin 3)

I'm driving an LCD HD44780 display using my Raspberry Pi B+.

Using a GPIO pin I'm managing the contrast adjustment (pin n. 3) on my LCD display with PWM.

In the display datasheet, I tried to search something that talks about minimium resistor between the GPIO out pin, and the contrast adjustment pin on the display, unsuccessfully.

This is the HD44780 datasheet.

So I connect the display and I measured the current flow first without any resistor and then with a 1kOhm one. Here my result.

  Resistor  |   Current
------------|------------
0ohm    |   20mA
------------|------------
1000ohm  |   12mA


My questions are:

• Can my display/raspberry be hurt using the contrast adjustment without any resistor?
• Is 20mA a dangerous current for my display/raspberry?