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adrianj / RangeImaging

Various things related to range imaging - specifically the Victoria University PMD19k Range Imaging System
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PMD Cyclone3 - RAM Exceeded #1

Open adrianj opened 14 years ago

adrianj commented 14 years ago

PMD Cyclone3 design currently uses only on-chip block RAM for everything. As you might expect, it will not work on the hardware since it exceeds the RAM resources of the chip, specifically the M4k blocks Steps to take to rectify the issue:

  1. Investigate how much RAM is actually available, and find the size of the 'big' blocks.
  2. Modify the Nios II SOPC to use less blockRam, or at the very least to make better use of the 'big' blocks.
  3. Modify the dualram160x128xN code to have an optional size where only the middle 64x64 are used.
  4. Modify the ranger_process code to have smaller bit-width accumulator buffers. (could be as little as 10 or 12 and sitll give reasonable results).
  5. Remove output buffers TL and TR, since the minimum required is actually only 2 output buffers.
adrianj commented 14 years ago

There is of course the obvious solution: get the external DDR2 RAM to work. And sounds like Johnny has at least some going. Nevertheless, the current design has an option to use very little RAM where only a 64x64 group of pixels are implemented. Though still not tested in hardware.