I recently ordered a 128x128 graphic black/white display with a ST7541 chip-on-glass. It took me 2,5 days debugging and frustration to discover that they didn't wire SPI through the flatcable.
A big trap for beginners, when you use the datasheet of the ST7541 chip as a reference while coding.
So I rewrote my driver to parallel driving mode and everything is up and running now.
This got me thinking what would be the best option performance wise to continue my product development. SPI or 8080 interfacing?
I drive the display with an Atmega329 and we have enough pins to do 8080.
First I thought 8080 would be the fastest, but I'm not sure if
PORTD = displaybyte is a very fast and optimized way of putting so much data through.
I guess the SPI architecture and MOSI pin is designed for higher data throughput? Or are they basically behave exact the same way?