Always better when it works to good effect to enjoy it when done.
What display is in use? Looks like it could be an ILI9341 shown on the breadboard - there are variants of the good _t3 library that do DMA updates from a buffer in the background
Yes it's just a cheap ILI9341 type screen, Thanks I will take a look at those libs.
In order to optimize the displays on Teensy 3.x systems, you will need to make sure both the CS pin and the D/C use the SPI0 fast pins. From the picture it looks like you are using pin 10 and pin 9 which are fast pins. The pins are:
- Pin 10 or pin 2 (but not both at the same time)
- Pin 9 or pin 6 (but not both at the same time)
- Pin 15/A1
- Pin 20/A6 or 23/A9 (but not both at the same time)
- Pin 21/A7 or 22/A8 (but not both at the same time)
- https://forum.pjrc.com/threads/33014-SPI-Chip-Selects-(Teensy-3-1-vs-3-2)?p=96072#post96072
Teensy 4.0 is different, and you pretty much have to use pin 10 on the first SPI bus for CS.
If you are sharing the SPI bus you want to use pull-up resistors in parallel between each of the CS and D/C pins and 3.3v. I imagine it also helps with high speed delays when there is only one thing on the bus. In my uncanny eyes setup (two displays), I've used 2.2K resistors. Using the pull-up resistors allowed me to bump up the SPI bus speed to run faster without screen corruption.
Obviously keep the wires as short as possible.
In the SPI setup, you can specify the SPI bus speed, and some of the display libraries allow you to specify the speed. You can use this to tweak the display faster.
PJRC sells ILI9341 displays are tested (random displays you get from ebay, etc. may/may not have issues). The page also lists the main library and two alternative libraries:
Teensy 4.0 is different, and you pretty much have to use pin 10 on the first SPI bus for CS.
If you are sharing the SPI bus you want to use pull-up resistors in parallel between each of the CS and D/C pins and 3.3v.
If you need optimized SPI with DMA, such as running two displays, the posts I see from KurtE, mjs513, and defragster indicate that you should put each display on a separate SPI bus:What's the advice for having multiple devices on the SPI bus on a Teensy 4? Are there other pins that are recommended beyond pin 10?