Receiving LVDS using NIOS II

Hi Michael,

I don't think you will be able to display the raw samples continuously.

I'm not sure that you will be able to transfer them over USB either. You would need to perform tests to see what the maximum bandwidth you can achieve over the USB interface is. Ignore what the performance 'could be' based on the USB specification - you need to measure what it actually is. Performance depends on what you have sending and receiving data over USB.

However, your display could be used as a logic analyzer to show blocks of samples, or as a spectrum analyzer to show the power spectrum. Or if you were to do some image processing, perhaps an image.

The NIOS processor can be used as a controller, and for some signal processing, however, its highly unlikely it will be able to do any sustained processing of the 65MHz samples directly.

For example, lets say you read an ADC sample, scaled it by two, and wrote that sample back to memory. Write some assembly code to do that, and then simulate it in Modelsim. The performance over the data bus will give you an idea of the maximum rate that the NIOS core can actually move data. I'm pretty sure you will be disappointed.

In signal processing systems, you usually connect signal processing blocks in a streaming fashion, eg. the ADC data goes through a gain block, and then into the next block. The job of the NIOS processor is to write to the gain register to keep power levels where they need to be for optimal processing. The NIOS processor does not have to be particular powerful for this 'control plane' task.

Cheers,

Dave