DE0 old problem Pixelbuffer and SDRAM

[Altera_Forum]

Hey Guys, 

I'm working with NIOS on the DE0 board, using SOPC Builder. I managed to get the pixelbuffer working in connection with the on chip memory. But if I use the sdram and not the on chip memory I only get a very colourful picture....  Can anybody help me? I tried to simulate the hole process in ModelSIm but the Programm didn't load everything (error messages).

[Altera_Forum]

Do you see color stripes at the top of the screen? If so, the stream underflow might be the reason. Increase clock frequency and see what will happen.

[Altera_Forum]

Hi, 

thanks for your reply. The hole TFT-monitor is full of stripes and some colourfull pixels.(Picture) Do you mean I should use an extra PLL and increase the clock for the SDRAM?  I looked in the data-sheet of the sdram and created an excel-file to calculate the phase delay. Maybe I can use the Alt avalon pll to realize it... I will test it.

[Altera_Forum]

It's strange. If i use the on chip memory, load the .sof to the Board, then change the memory to sdram, create and compile everything and load then the file to the board everything seems to be ok. 

If I close the programm and load the same .sof to the board, I get the picture....