Forum Discussion
Occasional Contributorusing DSPs in the FPGA as ALMs for standard FFT IP
Hi,
We are using standard FPGA FFT IP for our design given by intel.
we want to use many FFT IPs parallely for that the problem that we are seeing is resources for ALMs required is not suffiecient with the fpga availability.
It has sufficient amount of dsp available in the fpga.
So, is there any way for that fft ip to consume some of the DSPs in the fpga for some part of logic instead of ALMs so that we can fit more parallel ffts in our design and use all the ALMs and DSPs effectively.
As this is critical for us any answer soon helps us a lot.
42 Replies
KennyT_alteraSuper Contributor
May be you can create one simplified design and post it here. I will help you to sort this out.
VenkateshSatharadded a project with only fft2048 ip and added the attributes also. since I am used to vhdl , you will see top module with vhdl. here also same situation as discussed only ALMS consuming. quartus 16.1.2 I used. And for my other developments also using same quartus version.
- KennyT_altera
Thanks for attaching the design.qar files. Looking into the FFT module, most of the .v is encrypted. DSP block usually was used when there are multiplication take place. Since those files are encrypted, you cannot force those design to use the dsp block.
Unless you create your own design, then you will have better control of it.
- VenkateshSathar
But You can see in your datasheet it will consume DSPs but according to the datasheet also not happening no. Then how the number in the datasheet for DSP consumption given.
- KennyT_altera
Can you send me the link of the datasheet. I will investigate it.
- VenkateshSathar
https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/ug/ug_fft.pdf
under resource section you can see this table
- KennyT_altera
It took me few hours to debug it. Seems like your ip is corupted. I recreated it and it is working now. Will attached back your design.qar shortly
- VenkateshSathar
did you recreated it in 16.1.2 quartus standard edition only?
- KennyT_altera
Here you go!
- VenkateshSathar
you created the entire thing with 18.1 tool. I am using 16.1 tool. It's not happening with 16.1 quartus tool. I want the solution for 16.1 tool.
- KennyT_altera
Here you go for 16.1!
- VenkateshSathar
The whole point is that you are doing this project from start with 16.1 something you made in 18.1 downgrading or something like that to 16.1 so it is working. I applied your things in other project of 16.1 and nothing is working , I just saw the synthesis settings to match everything and all are same. still DSP are not getting consumed. In your project given by you also you can see the difference between the component you instantiated and actual block is different of the IP, you can the see in the following picture. If possible please try to create everything from scratch in 16.1 and show me this happen, otherwise no use.
you can source_exp in block diagram but you mentioned fftps_out which is in 18.1 IP component.
- KennyT_altera
Thanks, I will recreate this from scratch for Q16.1 tomorrow. Any reason that you cannot upgrade to Q18.1? As this might be an old Quartus bugs.
- VenkateshSathar
Our entire project provided by our vendor is with 16.1 only , over that we are developing some algorithms. Looks like vendor right now will not upgarde project to 18.1 with his custom made DSP Builder related IPs etc and give us.So, we are also proceeding with 16.1
- KennyT_altera
I check in Q16.1, it does seems to be a bugs as Q18.1 does not face this issue. What you can do is the follow:
1) download and install Quartus 18.1
2) copy the files from the Q18.1 (<quartus_install_dir>/ip/altera/dsp/) to the Q16.1
This will make your Quartus 16.1 make used of Q18.1 dsp block. As long as quartus able to compiles, the functionality should be fine. However, you have to make simulation to double check.
Thanks,
- KennyT_altera
Also, you will need to recreate the IP in Q16.1 to make it work, in your project navigators -> Ip components -> double check the IP is using 18.1 version
- VenkateshSathar
how to make it happen to use 18.1 FFT in 16.1 quartus software. For that also some background folders of the IP in installation need to copy from 18.1 is it?
- KennyT_altera
Have you follow the above steps that given? If you follow the steps, you should not have the question how to make it happened.
Basically, Quartus detect hw.tcl files for all the IP that is using. If you move over the whole dsp folder, all the necessary files will be copied over and you will see it like I mention above.
- VenkateshSathar
I am unable to download you 18.1 software now i think due to some other problems of your website. because for any account login for download coming like this only. After solving this by you guys only I can try i think so😕
