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STM32F7 delay and Long FIR

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Mon, 05/15/2017
8:43pm
brettcoupe
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STM32F7 delay and Long FIR

Hi , I purchased the STM32F7 dev Board to evaluate Audio Weaver to see how it would fit .

 

I have a couple questions.

1) I was previous advised  that 4ch of 1sec delay and 4ch of 1000p FIR filters would fit. However running just 2 ch or 700ms delay runs the CPU at 62% at 700ms and 3% if no delay blocks are drawn

is there a larger delay block as the delay block is 10ms max so I have to cascade 100 blocks to get 1sec

Maybe this is causing the large CPU useage

2) YouTube shows a Long FIR block, However I cannot see such a block in Audio Weaver? Does it existing in Audio Weaver anymore?

 

Thanks

 Brett

Tue, 05/16/2017
12:26pm
Axel Nilsson
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Hi Brett,

 

If you right-click on the delay modules and select View Properties, you can change the maxDelay parameter to 1000 milliseconds under the Arguments tab. The maxDelay argument determines how much memory is allocated for the delay module - during runtime, you will be able to tune the module to have a delay anywhere between 0 and maxDelay milliseconds.

 

Four channels of a 1000 tap FIR filter is a heavy load for the STM32F746. While testing with 4 channels, I was only able to get up to a 350 pt FIR and a 1 second delay before I started missing audio blocks on the 746 board. You may have to use a more powerful processor or a shorter filter to achieve your design.

 

The Long FIR block you saw on YouTube is DSP Concepts IP and is not released in the STMicro edition of Designer.

 

I hope this helps you, let me know if you have more questions.

-Axel

 

 

 

Thu, 05/18/2017
10:33pm
brettcoupe
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Hi

Yes I get 6% total CPU useage running 4 x 1 Sec Delay now.

Is the LONG FIR more efficient than the one than comes in teh ST edition.

are you able to try if 4 x 1 Sec and 4 by 1000p LONG FIR fit ?

 

Thanks

Brett

 

 

Tue, 05/23/2017
3:15pm
Axel Nilsson
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Hey,

Yes, the STM32F746 can handle the 4 channels of 1 second delay and the Long FIR filter module with 1024 pts. Note that the Long FIR filter gets more efficient with larger block sizes. Doing a quick test at 64 points, about 80% of the CPU was utilised. At 512 points, only about 51% of CPU was utilised. 

 

-Axel

 

Tue, 05/23/2017
11:57pm
brettcoupe
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Hi Axel

 Thanks for taking the time to try this

Given I want to use the STM32 for Other Work "WEB" and sockets I might look for a bigger CPU

Regards