I have a 1.8" TFT color display from Banggood. It's very nice with the vivid colors.
However, the screen refresh is slow. I'm limited by the SPI speed of 1 MHz. It results in an update rate of:
160 pixels x 128 pixels x 16 bit/pixel ÷ 1 MHz = 0.33s per frame
Effectively, it's even lower as the Teensy LC stops for about 1 cycle after each byte and there is overhead between the SPI transactions. So it's more like 0.5s per frame or 2 fps, which is very noticeable. It's more like a left to right swipe animation (see image below).
So my question is:
- Is the speed limited by the display controller chip, probably a ST7735?
- Or is the speed limited by my breadboard wiring?
- Is there a faster display available where I could use the SPI bus at 4 or 8 MHz?
Here's a picture of the bottom of the board.
Not much to see:
- The SD card slot and the three resistors R1 to R3 are not used.
- The resistor R4 close to the LED pin (right most on the image) is connected to the LED pin and has 7.5Ω (7R5).
- The part with three legs in the top corner reads "V2PK". I guess it's a voltage regulator that would be used for 5V operation. I operate it a 3.3V. There's also a capacitor and an open jumper close to it.
The interesting part is probably hidden between the PCB and the display.