Content originally posted in LPCWare by wellsk on Thu Jan 12 09:40:36 MST 2012
Hi Bourgeois,
You cannot use the internal 64K RAM bank for the LCD frame buffer. The internal AHB bus isn't attached to that memory or FLASH. For the internal IRAM, it can only be used for code/data space for the CPU and the general purpose DMA. You can get an idea of the bus matrix connections in the "CPU and busses" block diagram in the lpc177x user manual.
You can use peripheral RAM for the LCD frame buffer or external memory on the External Memory Controller.
For a 320x240 pixel display at 16bits/pixel(bpp) (2 bytes/pixel), this would require about 150K. Even at 4bpp, it would still require more memory than the peripheral RAM provides.