LCD interface to DM355 EVM

I believe the closest we would have to what you are looking for is SPRAAN0 available at the URL below, though this document is specific to the DM6446, much of it will apply to the DM355 as they share a similar VPBE interface.

http://focus.ti.com/dsp/docs/dspsupporttechdocsc.tsp?sectionId=3&tabId=409&familyId=1302&abstractName=spraan0

The DM355 EVM actually appears to have the same VPBE connector on it as the DM6446 DVEVM board, so it is possible that a LCD board that was made for the DM6446 DVEVM will work on the DM355 EVM. As mentioned in the SPRAAN0 document, Logic PD had created a board for this purpose, however I cannot find it on their site, you may want to contact them at dsp_team@logicpd.com to see if they have had anyone use the LCD with a DM355.

As to using the composite output at the same time as the digital LCD output, this is theoretically possible but is not practical for most applications as the VPBE was not designed for use as a multi channel video display. The main reason this will not usually work out is because you can only have one video stream going through the VPBE so both analog and digital will have the same image, and you only have one timing configuration available, so the on chip video encoder module and DAC must have the same exact configuration as what is coming out of the digital side. This will not work as most any LCD you have will not be able to deal with the configuration you have to use to get the DAC to output a NTSC signal. There is nothing stoping you from enabling both the analog and digital outputs on the VPBE, but I have yet to see an application where this is practical to use due to the limitations.