Helium328PU:
Could anyone confirm me, that SPI LCDs are much slower than parallel (8 or 16 bit) connected ones?
I am asking because mine with ST7735 redraws really slow (2sec for full screen area) and I want to know if this is normal or if it needs some tweaks or library mods.
I can't confirm it but I think serial is slower than parallel. I only have a Uno and a SPI Philips LCD 132x132, but managed to tweak some slow library for it from a very slow clearing speed up to about 21Hz. I broke apart compatibility, lowered the number of colors and sacrificed memory for performance. Now the screen flickers between updates, and I don't know how to get rid of that. Anyways, logically thinking, sending one or two bytes at once over parallel interface should always be faster than syncing the same data over SPI bit by bit like this.. I would need a similar parallel LCD for testing to know better though.
Edit: The obvious solution to flickering was not to clear the whole screen if only very few pixels changed state..