I've developed a project using am ILI9341, ESP12F and Arduino. Everything works fine except a very annoying issue. The LCD flickers when I use the laptop's USB. But when I use a USB charger it's much better.
I use https://github.com/Bodmer/TFT_eSPI library for SPI driver and AMS1117 as regulator (with 1uf in the input, and 10uf in output).
I don't think the software has a problem because I don't refresh anything on the display (just draw something in the setup function, not in loop) and also it changes with different power sources. The problem is the backlight.
When I move the USB cable it goes crazier sometimes. I've checked it with many different cables and computers. Is this because of noise or something from the USB port? How can I fix this?
It's very important for me to be able to use the USB port as the power source.
When I'm uploading the code to the ESP8266 (using TXD & RXI), the LCD doesn't flicker event a little bit! And immediately after finishing the upload, the LCD brightness decreases and starts flickering!
The circuit is pretty simple and LCD pins are connected directly as listed here