2095 - LatticeECP3: How does the Big/Little Endian switch mode affects the functionality of the FIFO DC?

2095 - LatticeECP3: How does the Big/Little Endian switch mode affects the functionality of the FIFO DC?

The Big/Little Endian mode switch will affect the word order when read data bus width and write data bus width are set as different values:

  • Case 1: write data bus width is 36bits and read data bus width is 18bits
    • For the Big Endian mode: if write Data[35:0], you will first read out Data[17:0] and then Data[38:18].
    • For the Little Endian mode: if write Data[35:0], you will first read out Data[35:18] and then Data[17:0].
  • Case 2: write data bus width is 18bits, and read data bus width is 36bits:
    • For the Big Endian mode, first word written into FIFO is shown at Q[17:0] when read out.
    • For the Little Endian mode, first word written into FIFO is shown at Q[35:18] when read out.