AMC1306E05: CLA and DMA

Hi Danilo,

We will get back to you shortly.

Thanks,
Ashwini

Hi Manoj,

Thank you for response. According to our customer,

So far I haven't been able to continue with my problem, but I'll try a few things tomorrow and maybe I need more support on SDFM.

Regarding to your answer:
"SDFM does all the filtering and CLA / DMA / CPU is used only for reading the filter results. Many customer use either DMA / CLA instead of CPU leave CPU bandwidth for other things."

Thats what i assumed. But curiously the implementation via MATLAB / SIMULINK needs a lot of time/bandwidth of the CPU. To much that it is "just" a reading and saving the SDFM-Values. Thats the background of my question.

Tomorrow i will try to implement a DMA for reading the SDFMs output values and saving them into the RAM for further calculations.

Regards,

Danilo

Danilo,

We already have C2000Ware example which shows how to use SDFM with both CLA and DMA. Feel free to adapt this example to suit your application.

Path: <C2000Ware>\driverlib\f2838x\examples\c28x\sdfm

sdfm_ex3_filter_sync_dmaread

sdfm_ex2_filter_sync_claread

Regards,

Manoj

Hi Manoj,

We have received this feedback from our customer,

I think my problem is solved now.

I use simulink for programming and i think there is a bug or something goes wrong by implementing the SDFMs into an ISR. I solved the problem by direct memory copy from the SDFMs DATA register into the ISR where the values are needed. But normally the SDFMs should be controllable like an ADC because it is a periphal which saves its values into a register..

Till yet i dont use the DMA function because it does not work for me. In the future i think i will use this.
But the using of the DMA should not be part of this case.

I have one last question - just for understanding:
I copied the Data for the SDFM1, Filter 1 from " 0x00005E17 " - i have found this by debugging with CCS.
But in the technical reference manual the adress is given with " SDDATA1 : 0x5E16".
Why is there a difference of 1 ?

another short question:

What is the advantage of the "SincFast" filter in comparission with Sinc1, Sinc2 or Sinc3 Filter?
In the technical reference manual, figure 14-7 i can see the frequency behavior of all 4 filters.

The filtering characteristic of sincfast is obviosly the poorest. In addition table 14-2 tells me that the order of the SincFast filter is 3 (highest order) and hence, the filter has the highest latency (slowest filter).

That doesn't make sense to me. Either a filter is fast with a bad frequency response or vice versa.

Regards,

Danilo

Hi Manoj,

According to our customer,

I think so far I have just one last question for your product specialist:

> SincFast provide better performance than Sinc2 and lesser performance than Sinc3.

If i understand the technical reference manual correct, the latency of the SyncFast filter is the same like the Sinc3 filter which means the highest latency of the filter settings. Is that correct?

Why is this filter settings name "SyncFast" ? - Is there another value beside Data rate and Latency which would explain the attribute "fast" ? What filter setting would you prefer ?

Regards,

Danilo