I am doing some Graphics Testing and find that I am running out of On-Chip RAM (1280 x 768 RGB565). This size is consuming about 3.9MB.
I spent time looking for how to conifgure SDRAM in FreeRTOS and was unable to find examples, but did see some U-Boot Examples. Using these, I was able to configure SDRAM (meaning I can read and write to memory locations and the data seems stable), but if I try to use this SDRAM space rather than the On-Chip RAM, the information to the display is not correct. If I define the FrameBuffer to be smaller (say 800 x 600), I am able to display correctly, but 1280 x 768 only displays correctly in on-chip RAM.
The only change between On-Chip and SDRAM is the line in the Linker file defining the address for VRAM (0x82000000 - on-chip RAM vs 0x94000000 SDRAM). These are the UnCached location.
I am beginning to feel I am missing something in setting up SDRAM which is limiting the bus bandwidth, but again, I am unable to find a FreeRTOS implementation to know what I am missing. I did ensure the CKIO is 132MHz, but I am not sure if there are any other performance settings in the micro to max out the throughput.
Any suggestions for where to check??