Electrical – LCD TFT Voltages

It's very possible that you'll never find a datasheet. Reverse engineering may be your best option for understanding what you have.

I recommend that, rather than dissecting a dead one - study a live one.

I would work from the bottom up. First find the LCD lines, look for meaningful signals. Use a logic analyser or oscilloscope to determine the type of bus and the shape of a transaction.

For example, for SPI you'd see a chip select, a square wave clock and two data lines. For RGB video, you might see three analogue ouputs with luma components. Or, for CVBS/Composite you might observe a colourburst.

Once you can take some action on the original device and predict the signals to the LCD, you can clone it.

Build a software implementation on your microcontroller to output the same patterns. Observe that it drives the LCD in the same way.

Alter the behaviour of your software driver repeatedly in small meaningful ways to discover how inputs relate to outputs. Try to determine the effect of flipping bits in the data and the effects they have, use this to guess at the data format.

This is a pretty common pinout for an LCD. You can be pretty confident that it uses the Hitachi HD44780 chipset. The LiquidCrystal library should be able to drive it without any trouble. The K and A pins are just backlight power pins.

Any digital pins should work... just make sure you connect the pins to the LCD the way the comments in the example suggest. You just need to map the pins you are connecting to the signature of the constructor being used in the example.

lcd(12, 11, 5, 4, 3, 2); 

is using the constructor from the library docs that goes with:

LiquidCrystal(rs, enable, d4, d5, d6, d7) 

You know this by counting the number of arguments. So in the example:

• Digital 12 == RS == LCD pin 4
• Digital 11 == Enable == LCD pin 6
• Digital 5 == D4 == LCD pin 11
• Digital 4 == D5 == LCD pin 12
• Digital 3 == D6 == LCD pin 13
• Digital 2 == D7 == LCD pin 14

You obviously also have to connect LCD Pin 2 to 5V and LCD Pin 1 to GND. You may also need to hook up a potentiometer to LCD pin 3 to adjust the contrast. Which may be the problem you are describing in your comment to me above. There are literally hundreds of tutorials on line about this, use the google :).