The util_upack2 core is similar to the util_upack core. It unpacks, or
deinterleaves, a data stream onto multiple ports.
The upack2 core uses a streaming AXI interface for its data source instead
of a FIFO interface like the upack core uses.
On the output side the upack2 core uses a multi-port FIFO interface. There
is a single data request signal (fifo_rd_en) for all ports. But each port
can be individually enabled or disabled using the enable signals.
This modified architecture allows the upack2 core to better generate the
valid and underflow control signals to indicate whether data is available
in a response to a data request.
If fifo_rd_en is asserted and data is available the fifo_rd_valid signal
are asserted in the following clock cycle. The enabled fifo_rd_data ports
will be contain valid data during the same clock cycle as fifo_rd_valid is
asserted. During other clock cycles the output data is undefined. On
disabled ports the data is always undefined.
If no data is available instead the fifo_rd_underflow signal is asserted in
the following clock cycle and the output of all fifo_rd_data ports is
undefined.
This core is build using the common pack infrastructure. The core that is
specific to the upack2 core is mainly only responsible for generating the
control signals for the external interfaces.
The core is accompanied by a test bench that verifies correct behavior for
all possible combinations of enable masks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Lars-Peter Clausen