For consistent simulation behavior it is recommended to annotate all source
files with a timescale. Add it to those where it is currently missing.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Some parts of the util_cdc library rely on dead logic elimination to remove
unused logic. Unfortunately with newer Vivado versions this results in
warnings about unused sequential elements being removed. Like:
WARNING: [Synth 8-6014] Unused sequential element cdc_sync_stage1_reg was removed.
To avoid this encase the logic in generate blocks that makes sure they are
not generated when not needed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Currently the individual IP core dependencies are tracked inside the
library Makefile for Xilinx IPs and the project Makefiles only reference
the IP cores.
For Altera on the other hand the individual dependencies are tracked inside
the project Makefile. This leads to a lot of duplicated lists and also
means that the project Makefiles need to be regenerated when one of the IP
cores changes their files.
Change the Altera projects to a similar scheme than the Xilinx projects.
The projects themselves only reference the library as a whole as their
dependency while the library Makefile references the individual source
dependencies.
Since on Altera there is no target that has to be generated create a dummy
target called ".timestamp_altera" who's only purpose is to have a timestamp
that is greater or equal to the timestamp of all of the IP core files. This
means the project Makefile can have a dependency on this file and make sure
that the project will be rebuild if any of the files in the library
changes.
This patch contains quite a bit of churn, but hopefully it reduces the
amount of churn in the future when modifying Altera IP cores.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
This reduces the amount of boilerplate code that is present in these
Makefiles by a lot.
It also makes it possible to update the Makefile rules in future without
having to re-generate all the Makefiles.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Add a set of helper functions for the CDC library that creates the correct
constraints for the CDC blocks. This makes it easier to specify the
constraints in the individual user's SDC files.
This only works for Altera where full scripting capabilities are available
in the SDC files.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The sync_data module can be used to continuously transfer multi-bit signals
like status signals safely from the source to the destination clock
domain. A transfer takes 2 source and 2 destination clock cycles. It is not
guaranteed that all transitions on the source side will be visible on the
target side if the signal is changing faster than this. Logic using this
block should be aware of it. The primary intention is for it to be used for
slowly changing status signals.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
The event synchronizer can be used to safely transfer 1-bit 1-clock cycle
event signals from one clock domain to another.
For each event recorded in the source domain it is guaranteed that a event
will be generated in the target domain at a later point in time. It is
possible though that multiple events in the source domain will be coalesced
into a single event in the target domain if events are generated faster
than they can be transferred.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Move the CDC helper modules to a dedicated helper modules. This makes it
possible to reference them without having to use file paths that go outside
of the referencing project's directory.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Istvan Csomortani
Adrian Costina
Lars-Peter Clausen
Rejeesh Kutty