UFO Operation

Timeouts

• The DMA timeout is at least 50ms
• The bellow is explained how long it takes to read frame by hardware. We also need to add DMA timeout + PCIe transfer time on top of that before we can expect to acquire frame

  ð  Yes, I wish to fix this definitively. We can assume for today and for the future that we want to use only microsecond time (not nanosecond) in the follows way:  total time = integration time + readout time + back pressure from PC/DMA
  
  ð  Integration time  à set by  Libuca so that you know well (microsecond)
  
  ð  Readout time = number of rows * time per row. Now, number of rows à set by Libuca (you know) and the time per row is:
  
  o   = 13us for 4MPixel @ 11 or 12 bit
  
  o   = 3.3us for 4MPixel @ 10 bit
  
  o   = 2.7us for 2MPixel @ clock 48MHz (in this case only 10bit is available)
  
  ð  back pressure from PC/DMA à this is very variable and depends from the PC status not from the electronics.
  
  ð  The DMA timeout is  67 ms that is too much. What we can do easily is to bring this timeout programmable by software, we will create a new register in the DMA bank register (address 0x64-0x68), so that you can define your timeout.
  

Frame Size (CMOSIS sensor)

• 10b:

  129*256*(number_lines -1) + 128*256 + 512 bits, or
  129*32*number_lines + 32 BYTES
  

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• 12b:

4*129*256*(number_lines -1) + 3*129*256 + 128*256 + 512 bits, or 
4*129*number_lines + 32 BYTES