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Carry Chain COUT drives multiple net sinks #1597
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Which version of symbiflow-yosys where you using? |
@litghost This was with the old master+wip ( |
Can you please make a PR that demostrates this bug? I can try to take a look at it after I make #1577 green. |
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
I've replicated the issue, debugging now. |
I think I know a fix, will test it soon. |
My fix brought in other issues, trying a different approach. |
I have an approach that appears to P&R, unknown if it works in hardware. I'll test that tommorow. |
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
@acomodi When you updated the base LiteX, I think the SDC and PLL settings got out of sync. Can you double check what is going on there? Specifically, from Vivado propigation:
From SDC:
|
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Right, I checked and I missed to set the clock frequency of the system at 60 MHz when generating the design. I will generate a new one and update the PR |
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
f4pga#1597 Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
When updating the baslitex test with the newest version of Litex, I have encountered the following assertion failure in VPR:
The assertion checks whether nets between macros (in this case carry chains) have more than one sink. This because a net connecting to blocks in a macro should not drive other sinks, as this would create inconsistencies with the macro placement.
I have tracked down the possible cause of the issue being in the fact that COUT pins from carry chain get to be connected to external nets rather than just the CIN pin of a next carry in the chain (if no other carry is present in the chain, the COUT pin should not be connected to any other sink).
eblif:
From the eblif, we can see that the COUT pin is present in multiple nets, so this issue most probably relates to the yosys step.
top_synth.v:
Also in the verilog representation, the CO_CHAIN output is connected to an assign statement.
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