RGB backlight negative LCD 20x4
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- k5map
- Posts: 135
- Joined: Sat Apr 18, 2015 8:52 pm
RGB backlight negative LCD 20x4
I just wired up my new RGB backlight negative LCD 20x4 (Product ID: 498). Its working great for Blue & Green but Red is not showing up at all. Is the Red colored controlled solely via pin 16 (-R) on the LCD?
- adafruit_support_bill
- Posts: 88097
- Joined: Sat Feb 07, 2009 10:11 am
Re: RGB backlight negative LCD 20x4
That is correct. If you connect a jumper from pin 16 to GND, does it light up?
- k5map
- Posts: 135
- Joined: Sat Apr 18, 2015 8:52 pm
Re: RGB backlight negative LCD 20x4
The LCD does light up but no change in the color (not showing Red). I did notice as soon as I apply power to the display, it shows a Green background. And when Red or Yellow are shown using the example Python script, it shows the text in Green. Blue and Green text do show up in the correct color.
- adafruit_support_bill
- Posts: 88097
- Joined: Sat Feb 07, 2009 10:11 am
Re: RGB backlight negative LCD 20x4
Sounds like a defective backlight module. Please contact [email protected] with a link to this thread and we can replace the display.
- rbbtebo
- Posts: 57
- Joined: Tue Aug 18, 2015 9:12 am
Re: RGB backlight negative LCD 20x4
Good morning, Adafruit!
I'm about to hook up a 20 x 4 RGB LCD. In reading the tutorial, it shows Pin 15 going to +5V. However, it reading old posts, I saw a post by adafruit support - Rick on 3/15/11 that says pin 15 should go to ground....
I'm confused and don't want to burn things up. Help! - Which do I hook Pin 15 up to?
Also, I'll be driving it with a PRO Trinket. My understanding is that the PRO should work like a UNO.... I saw some posts referring to standard Trinket and special libraries needed.... For the PRO Trinket - can I just use the standard libraries?
Thanks always for your help!
Balad
I'm about to hook up a 20 x 4 RGB LCD. In reading the tutorial, it shows Pin 15 going to +5V. However, it reading old posts, I saw a post by adafruit support - Rick on 3/15/11 that says pin 15 should go to ground....
I'm confused and don't want to burn things up. Help! - Which do I hook Pin 15 up to?
Also, I'll be driving it with a PRO Trinket. My understanding is that the PRO should work like a UNO.... I saw some posts referring to standard Trinket and special libraries needed.... For the PRO Trinket - can I just use the standard libraries?
Thanks always for your help!
Balad
- rbbtebo
- Posts: 57
- Joined: Tue Aug 18, 2015 9:12 am
Re: RGB backlight negative LCD 20x4
Also - do I need current limiting resistor for the LED?
- adafruit_support_bill
- Posts: 88097
- Joined: Sat Feb 07, 2009 10:11 am
Re: RGB backlight negative LCD 20x4
Pin 15 is the 'common anode' and should be connected to +5v. Pins 16, 17 & 18 are the R, G and B cathodes. These already have current limiting resistors on board.
- rbbtebo
- Posts: 57
- Joined: Tue Aug 18, 2015 9:12 am
Re: RGB backlight negative LCD 20x4
Awesome, Bill. Thank you as always.
Will I have any problems using the PRO Trinket?
Will I have any problems using the PRO Trinket?
- adafruit_support_bill
- Posts: 88097
- Joined: Sat Feb 07, 2009 10:11 am
Re: RGB backlight negative LCD 20x4
Sorry, I missed the second half of your question.
You should not have any problems with the Pro Trinket. It has the same Atmega328 processor as an UNO. Other than a couple of pins reserved for the USB interface, it performs pretty much like a standard UNO.
You should not have any problems with the Pro Trinket. It has the same Atmega328 processor as an UNO. Other than a couple of pins reserved for the USB interface, it performs pretty much like a standard UNO.
- rbbtebo
- Posts: 57
- Joined: Tue Aug 18, 2015 9:12 am
Re: RGB backlight negative LCD 20x4
Bill - you rock as always! Thank you and have a great weekend.
Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/