Hi
I have used the Keil Blinky example as a starting point to configure an Embedded Artists LPC2478 board external 32 bit SDRAM. I have recently started to run the eval board supplied QVGA LCD screen in RGB mode i.e. using the external SDRAM as a frame buffer for the LCD.
The problem I have is one of general SDRAM access speed. I have slowed the LCD controller refresh to the slowest speed possible so the LCD doesn't flicker so as not to occupy the SDRAM bus access too much. Then when clearing a block of SDRAM memory to clear the LCD display it takes a finite time but is clearly visable to the human eye when looking at the LCD. I can see the LCD 'swipe' across as the SDRAM is written to in a loop.
The micro is running at 72MHz and the LCD is only 320x240 pixels, I hope to finally use a 800x480 pixel LCD but then the LCD clearing time would be even more noticable.
Am I expecting too much from this micro and its built in LCD controller? Ideally I need to get the SDRAM block writes much faster so the LCD updates are less noticable.
Thanks in advance for any suggestions.