Delay balancing error while using HDL coder

Hello

I am using Matlab 2023b version. While generating the HDL code I am facing the issue with delay balancing.I received the following error:

" Delay balancing unsuccessful because an extra 10 cycles of latency introduced by optimizations in the feedback loop cannot be offset using design delays for the loop latency budget. If you are modeling at data rate (high-level description of algorithm without hardware implementation details), refer to the clock-rate pipelining report for more details. If you are modeling at clock rate, consider increasing the latency budget by adding more design delays in the feedback loop. Refer to the delay balancing report for more details."

I inserted some delay blocks in series with the error block,but still the error remains same.I didn't faced this issues when I was generating using 2021 version.Do I need to change anything in the setting?. Is there anything I should do with the delay blocks.

Answer 1

[Kiran Kintali]

Hi Sanil,

would you be able to share your model? Do not hesitate to reach to technical support and we can help further assist you.

You usually run into this situation when using blocks that request latency within feedback loops and clock rate pipelining has not sufficiently kicked in.

Please check enable the optimization report and check clock rate pipelining and delay balancing sections of the report for additinal clues.

https://www.mathworks.com/help/hdlcoder/ug/clock-rate-pipelining.html

https://www.mathworks.com/help/hdlcoder/ref/generateoptimizationreport.html

It is quite possible 2021 version didn't report the issue properly or handled your model correctly. I found these two bug reports 3056295, 3176370 that seem relevant; there could be others in the previous release.

>> I inserted some delay blocks in series with the error block,but still the error remains same.

There is a potential problem with identifying scattered delays in series that is fixed in R2024a release. Please consider using a lumped integer delay block with the correct delay in the model and see if it helps.

[SANIL]

Hi Kiran,

Thank you for replying. There is some problem with sharing the model. So can we have an online meeting to sort out this error. Also can you confirm whether these bugs which caused the error got fixed on 2024a version, so that I can go for it.

[Kiran Kintali]

Sure. please reach to the tech support and they will direct you to the right team. https://www.mathworks.com/support/contact_us.html

>>Also can you confirm whether these bugs which caused the error got fixed on 2024a version?

We strongly recommend moving to the latest release.