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RGB LCD with Backpack
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

RGB LCD with Backpack

by joshmcintyre on Thu Aug 08, 2019 11:31 pm

I was all excited to use my new LCD, but I realized after soldering everything together per the guide that the RGB character LCDs are not compatible with the I2C backpack :(

Is there anything I can do besides purchase a new backpack and non-RGB LCD screen?

I don't care about the RGB features at all, just the character display. Are there any known "hacks" for the CircuitPython library that would allow me to use what I have on hand?

Another option I can think of would be to de-solder the backpack from the other side of the attached header and then wire it up the "manual" way, but the backpack is certainly convenient which I why I ordered it...

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Re: RGB LCD with Backpack

by adafruit_support_bill on Fri Aug 09, 2019 5:44 am

The only difference between the RGB and non-RGB versions of the LCD is the backlight. The RGB has 2 extra pins for the G and B channels of the backlight.

If you connect it up directly - ignoring the last two pins, you will have a red backlight. Leaving out the last pin, you could use a jumper to select a red, green or blue backlight.

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Re: RGB LCD with Backpack

by joshmcintyre on Fri Aug 09, 2019 10:05 am

Thanks Bill! That makes sense. I get a red backlight no problem.

The reason I posted is that I can't seem to get a message to display using the character display library:

Code: Select all | TOGGLE FULL SIZE
       import adafruit_character_lcd.character_lcd_i2c as character_lcd

        # Initialize the board
        i2c = busio.I2C(board.SCL, board.SDA)
        cols = 20
        rows = 4
        lcd = character_lcd.Character_LCD_I2C(i2c, cols, rows)

        # Display the address or private key passed in
        lcd.message = "Hi"



Am I missing something code wise?

joshmcintyre
 
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Re: RGB LCD with Backpack

by adafruit_support_bill on Fri Aug 09, 2019 10:47 am

Do you see any thing at all displayed?
Try adjusting the contrast pot. (Be gentle, it is easily damaged if you turn it too far.)

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Re: RGB LCD with Backpack

by joshmcintyre on Sat Aug 10, 2019 3:28 pm

Hi Bill,

Sorry for the delayed response. I got back to my project last night and all I needed to do was adjust the contrast potentiometer. Everything is working now!

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Posts: 6
Joined: Thu Aug 08, 2019 11:07 am

Re: RGB LCD with Backpack

by adafruit_support_bill on Sat Aug 10, 2019 4:45 pm

Good to hear. Thanks for the update!

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Please be positive and constructive with your questions and comments.