LCD Doesn't work :(

:confused: I tried hooking up my LCD to TTL but it doesn’t work :frowning: Could it be that the TTL is not functioning properly or is it the wiring. I took the LCD and it has this backpack on it.

In the picture there are two but our backpac has the female end to it. and it has GND, 5V and RX so I took at pwm cable and placed it inside those three holes make sure that the black goes to GND, red goes to RX and white goes to 5V. Than I took that pwm cable and attached it to a TTL chip, the one that came with camera. Then mounted that TTL chip on the TTL port. After all that I took kevin’s code and downloaded, because according to the code the LCD is suppose to work automatically I assume. I see nothing :frowning: all blank no power nothing in LCD. Can someone please tell me where I possibly went wrong?
this is the LCD we are using:


The chip is converting from TTL to rs232. The backback uses TTL.
The wires on the TTL converter chip do not have power. They are rx/tx/gnd( I don’t know the order). Get power from a digital IO, and then try it with just the rx pin of the backback to the TX of the RC.
Do what i said below, and if it still doesn’t work you may have damaged the backback.
Get power from a digital io. Don’t connect the LCD to the serial port, just power. You should get:
SerLcd 1.0
or somthing similar. If you backback has been configured differentially it may not show the message, but its backlight should come on.

If you get light or message then connect just the rx pin to the tx pin of the TTL port.

Other than that I have used that device on an EDU and Vex without any issues.

I imagine you just have your wires crossed somehow.

Describe the connections you made on the FRC TTL port end.
Here’s a quick reference chart we use. The FRC TTL port is on the lower left…
Traditionally, we use red for 5v power and white for signal, but as long as you’re careful…

Are you doing this on the Full-Sized Robot Controller, Vex, or EDU?

P.S. Rereading this I forgot to make it clear that I agree with Eric about removing the TTL converter chip.

Typically on the IFI PWM wires, red is +5V and white is “signal”. You might try reversing those in your setup. Of course, what really matters is what’s connected at the other end. Make sure that the RX of the LCD panel is connected to the TX on the RC.

Make sure you have the correct baud rate.

i did connect LCD to digital Input and it didn’t work. I used digital input 6 and nothing powered up. So what should my next step be?

If it didn’t work off the digital input I wouldn’t be surprised if the rs232 signal damaged the board.

Check the solder at each of the connections between the backpack and the LCD.

If you can’t find any problems I would suggest contacting SparkFun support [email protected].