Nikki Cooper
New member
Hi!
I have a couple of the ILI9341 Color TFT 2.8 inch touchscreens that were recently purchased from the pjrc store.
Looking closely at the TFT PCB I notice its LED circuit is the following:
Simple enough. Given the above circuit which is already on the display PCB, I would like a confirmation that it is O.K. to connect Digital pin 6 (physical pin 8) on Teensy 3.2 directly to the LED pin on the display, dispensing with the usual 100R resistor between +5V VCC and the LED pin. As you have likely already surmised, I hope to use the PWM modulated output of the Teensy to control the display backlight brightness. Yes, I've searched for previous posts on this topic, and it seems some have successfully done this. From what I can tell, it completely depends on who designed a given display implementation, some have the LED backlight control electronics built in (like my display appears to have) and some don't. I'm almost positive I can do this safely but I've already managed to kill a Teensy 3.2 when attempting to interface to it via a simple high side switching circuit completely unrelated to the display due to a totally brain dead dumb mistake. So I'm going to be extra cautious just in case I'm misunderstanding whats going on here. Teensy is very unforgiving. Not a fault, but rather the nature of the beast. A nod of yea or nay from you experienced grey beards would be greatly appreciated.
TIA,
Nikki
I have a couple of the ILI9341 Color TFT 2.8 inch touchscreens that were recently purchased from the pjrc store.
Looking closely at the TFT PCB I notice its LED circuit is the following:
[ATTACH alt="2.8" TFT color display LED control circuit - 2.8" TFT color display LED control circuit" type="full" width="60%"]16897._xfImport[/ATTACH]
Simple enough. Given the above circuit which is already on the display PCB, I would like a confirmation that it is O.K. to connect Digital pin 6 (physical pin 8) on Teensy 3.2 directly to the LED pin on the display, dispensing with the usual 100R resistor between +5V VCC and the LED pin. As you have likely already surmised, I hope to use the PWM modulated output of the Teensy to control the display backlight brightness. Yes, I've searched for previous posts on this topic, and it seems some have successfully done this. From what I can tell, it completely depends on who designed a given display implementation, some have the LED backlight control electronics built in (like my display appears to have) and some don't. I'm almost positive I can do this safely but I've already managed to kill a Teensy 3.2 when attempting to interface to it via a simple high side switching circuit completely unrelated to the display due to a totally brain dead dumb mistake. So I'm going to be extra cautious just in case I'm misunderstanding whats going on here. Teensy is very unforgiving. Not a fault, but rather the nature of the beast. A nod of yea or nay from you experienced grey beards would be greatly appreciated.
TIA,
Nikki