add `LAST_ENABLE` to axis_arb_mux

alexforencich / verilog-axis

Verilog AXI stream components for FPGA implementation

MIT License

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add `LAST_ENABLE` to axis_arb_mux #15

Closed lomotos10 closed 3 years ago

lomotos10 commented 3 years ago

Adds the LAST_ENABLE flag to the axis_arb_mux module, that propagates the tlast signal in a similar manner to all the other AXI signals. (e.g. KEEP_ENABLE, etc.)

I believe the LAST_ENABLE flag should be needed for AXI4-Stream ports that do not use the TLAST signal.

Example: This change makes it possible for the event_mux module to be implemented using axis_arb_mux.

alexforencich commented 3 years ago

You also have to fix the acknowledge signal to the arbiter so that it ignores the input tlast signal. Specifically, it should act as if the input tlast signal is always high.

lomotos10 commented 3 years ago

Thank you for your comment. I've updated the PR so that:

the arbiter acknowledge signal now takes LAST_ENABLE into consideration
LAST_ENABLE=0 assumes that tlast is always high (originally assumed low)
no longer performs LAST_ENABLE = 0 test in test_axis_arb_mux.py