Our development system uses AM3703 interfacing with a 8-bit LCD supporting serial RGB from DataImage with 480x234 resolution. The LCD display panel uses white backlight. The HSYNC, VSYNC and CLK has been checked to be as per data sheet.
The DSS has been configured to use 24-BPP, 24-bit parallel interface to LCD. TDM block has been enabled to multiplex 24-bit RGB in 3 cycles of 8-bit interface width to LCD.
The configuration is:
DISPC_CONTROL register: TDMCYCLEFORMAT bit field is set to 0x2 (three cycles for 1 pixel)
DISPC_DATA_CYCLE registers for each of the color (R, G, B) has been set to 0x8. (use 8 bits on each cycle).
With the above setting,we are facing see couple of issues:
1. With TDM enabled as above, the X-resolution seems to be 3 times the configured value of 480. This factor seems to be controlled by the TDMCYCLEFORMAT bit in DISPC_CONTROL register. If it is set to 1 (2 cycles per pixel), the resolution seems to be twice the normal. With TDMCYCLEFORMAT to 3 and by loading the image with resolution 160x240, it gets displayed fine on the display with resolution of 480x240.
2. As expected for our case, the LCD displays color only when TDM is enabled and configured as above. However, the color is not perfect i.e. RED is not perfect RED, is a pale shade of the color. Similarly, Green and Blue. We have color issue.
Our system runs Linux 3.0.3 with Ubuntu filesystem.
Look for support, suggestions on mainly the color issue.
-Ganesh
