ECP5 FIFO experiments

2020-3-1

The FIFO from nmigen seems to work at 600 MHz in the 8x8 size, though in the 8x200 size, the data becomes garbled, starting to work again at slightly above 300 MHz.
It works by generating input data with a linear-feedback shift register, which adds a new byte to the FIFO. On the other side is another LFSR which gets compared to the FIFO output. If they don't match, the error counter is increased.
The counter is read out by the onboard LEDs at n/2^5, 2^10 and 2^29. Another LED shows the FIFO output divided by 2^28.
Failure was detected by looking at the error counter LEDs, usually the 2^5 one went half lit and the 2^10 one blinked, depending on the frequency of errors.
The FIFO from nmigen seems to work at 600 MHz in the 8x8 size, though in the 8x200 size, the data becomes garbled, starting to work again at slightly above 300 MHz.
It works by generating input data with a linear-feedback shift register, which adds a new byte to the FIFO. On the other side is another LFSR which gets compared to the FIFO output. If they don't match, the error counter is increased.
The counter is read out by the onboard LEDs at n/2^5, 2^10 and 2^29. Another LED shows the FIFO output divided by 2^28.
Failure was detected by looking at the error counter LEDs, usually the 2^5 one went half lit and the 2^10 one blinked, depending on the frequency of errors.




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