NI SPDIF Input Module

[Christian_L]

Actually 33 is the cutoff between the medium and long pulses. The pulse lengths themselves should be around 13, 26, and 39. So 40 is an expected pulse length, but ideally you should not have any right around 33.

I looked at the description of the Motorola DCT set top boxes and they all seem to output Dolby 5.1 Digital over SPDIF. This means that the audio data is encoded in the 24 data bits of each SPDIF packet instead of transferring the data as raw binary values. The examples we are working with only decode the raw data bits, but they do not decode any encoded audio such as Dolby Digital or DTS. So the noise you see is probably what we would expect at this point. I do not have any information on how to decode these other formats.

[Falcon]

Christian,

Thanks for your support! I have some final questions. How do you configure the FIFO in the second LabVIEW code which you sent to me? Never arbitrate, Always Arbitrate and so on. Also, How about the depth? 2048? Is it configured as a Memory Block? I guess so! Finally, how about the type? Target Scoped, Host to Target, or Target to Host? I guess it is Target to Host. Can you confirm?

Thanks again,

[Christian_L]

The FIFO is configured as follows:

Datatype: U32
Size: 4100
Type: Local

Memory Type: Block Memory
Read/Write Arbitration: Arbitrate if Multiple Accessors Only

Right now the FPGA VI uses the FIFO to transfer data from the SCTL to the other loop which transfers the data to the host. This should be changed to use a DMA FIFO (Target-to-Host) to transfer the data directly from the SCTL to the host application without needing the other loop. Of course this will require some changes on the host as well to configure and read data from the DMA buffer.

[Falcon]

Thanks for info.

Happy holidays,