Hi,
My customer is asking the below question on Display interface for AM335. Could somebody help me to get an answer to the customer.
Thanks in advance!
Background:
In the upcoming project, we need to connect and control 3 displays from the MPU. Our displays have a COG Controller including internal GRAM, and allow both connection via synchronous RGB-Inteface (Data, VSync, HSync etc.) and via asynchronous MPU-Interface (i8080 ro m6800 mode).
Idea:
Reading the preliminary AM335x manual, I saw that the LCD-Controller supports both synchronous and asynchronus displays. If my understanding is right, the LIDD controller is capable to transfer complete framebuffers to asynchronous displays via i8080 or m6800 interface type, using the same pins used for RGB output (LCD_Data, HSync, VSync etc.). Also, the LIDD suports 2 diferrent displays by offering CS0/CS1 selection.
Since we need to control 3 displays, I thought we could perhaps externally multiplex the CS0/1 line (switch physical connection via additional output pins from MPU), and during operation, to transfer pixel data from framebuffers to the displays sequentially in a loop (display 1, 2, 3, 1, 2....). Switching the CS line would be done by Software after a complete screen refresh of a display.
Questions:
1) What do you think about that concept, is it reasonable?
2) Is it right, that the LIDD supports DMA transfer of pixel data for a whole framebuffer?
3) What is the maximimun speed (pixel clock, refresh rate) we could achieve with that approach?
4) Are there any pitfalls we don't see so far?
5) Any additional remarks?