I'm using the LTDC peripheral to interface with a TFT LCD. It works great. Now I'm interested in rotating/orienting the display by 90 degrees. I have a couple approaches in mind -
- Doing some pointer gymnastics into the frame buffer that basically writes the pixel information into precise addresses that results in a "rotated" image.
- Somehow tell the TFT LCD panel to start writing the pixel information from the bottom to the top of the display. Instead of the default top to bottom.
I'm open to other approaches or maybe I'm missing an obvious way to do this. Maybe leveraging the 2 layers that the LTDC makes available? Somehow have one dedicated for landscape the other for portrait mode? I am not using the touchgfx library since I'm only interested in displaying still images and it looked to be more helpful for applications with UI's.
I'm researching the 2nd approach. Page 15 of the ILI6480BQ data sheet states that there is a register R1 in the TFT LCD driver that controls the scan direction with the "UPDN" bit. How can I communicate with the driver in the TFT LCD to update this register value? Is this done over the RGB interface? Is this even possible? I took a closer look at the LTDC documentation and the TFT LCD data sheet but didn't come up with how this is done. Could you share some guidance or let me know if I should abandon this approach?
Thanks.
