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BF548: access from program code to SDRAM ?

Question asked by PK.EMT on Jul 22, 2010
Latest reply on Jul 22, 2010 by PK.EMT



I have coded a framework for a PAL video application with 3 framebuffers:


  Video In over PPI and DMA to framebuffer x (SDRAM)

  Video Out over DMA and PPI from framebuffer x-2 (SDRAM)


So far the application works correct. But from the main loop of the program I need

an access to the framebuffer x-1 (working buffer for image manipulation). If I try to

read a byte from the framebuffer, the main loop stopps. The interrupt controlled

PPI/DMA process is working on. In this case I can not stop the debug session.

The reaction of VisualDSP++ is the following message:


  "JTAG scan failed

  Unspecified error

  DSP could not clear EMUIR"


I think the problem are missing or wrong entries in the linker description file, but I have

no idea to solve the problem.


The declaration of the framebuffers are:


  #pragma section("sdram0")

    char Buf1[2*720*576];

  #pragma section("sdram0")

    char Buf2[2*720*576];

  #pragma section("sdram0")

    char Buf3[2*720*576];


and I define a User Heap of 20 MB in Project Options.


Thank You for any help,