UP VGA Pixel Buffer

Hi,

I have a problem using the second Pixel Buffer.

I'm using the SRAM at 0x0000000 for the first one

and I have althoug configured the second one on

this adress in the SOPC-Builder.

Now I am manipulating the SRAM via some VHDL

code, which I connect via the External Master to

Avalon slave form the UP, which works fine.

Now in NIOS I created an buffer, within SDRAM ,

and passed the adress to the VGA-Framebuffer as

a the adress of the backbuffer, which also works fine,

at least in the debug mode.

But when I switch from first to second buffer, the adress

in the VGA-Pixelbuffer switches correctly but on the

screen nothing happens.

What's kind of weird is that sometimes I only can see the

Pixelbuffer stored in the SDRAM, but I can't find out how

this happens The only way to restore is then to unplug the

device from current.

Although my alt_alarm functions don't seem to work might

this be reason for my problem.

Thanks a lot for your help

Best wishes