1 Reply Latest reply on Jan 31, 2017 10:06 PM by nishanta_46

    AUTO DMA Channel for SPI to USB



      Can I have an infinite transfer AUTO DMA channel from SPI to USB end point. Is it possible to make the transmission happen only if fixed number of bytes got received from SPI each time?


      I want the audio samples coming at SPI (I2S converted to SPI) to go to USB endpoint without involving CX3 CPU.If an AUTO infinite DMA transfer can solve the problem, please help me how to do that. For audio class, how will we manage filling the bytes of audio frame in this case? Is it a byte by byte transfer ?

        • 1. Re: AUTO DMA Channel for SPI to USB
                  The DMA does not put any restriction on creating the channel from USB to SPI. But, the problem is that you have to set some preamble like address, data size and also assert control signals like ssn. These are the hindrance why you cannot directly do a USB to SPI transfer. That's the reason we have use FX3-CPU in all our examples where we have to do a SPI communication. The same is true for I2C as well.