I would like to interface my Terasic DE0-Nano running a Cyclone IV with an external SD card that I will attach to a circuit board that will also interface with the GPIO headers on the DE0. I'm pulling in multiple (>20) lines of binary data at approximately 160 kHz and would like to save it to an SD card that a Raspberry Pi will also have access to. The end product will essentially have the FPGA running independently of the RPi, which will periodically pull off data that the FPGA generates. Could someone please point me in the right direction as to how to do this?Thanks in advance.
you are implying that both the FPGA and the RPi somehow have simultaneous access to the SD card, is this correct? How do you intend to do that?It does not make sense to use SD card if this is true and data is only being buffered in the SD card.
Thanks for your reply, Xaui. The reason for the dual access to the SD card is because the experiment requires remote recording of multi-channeled PDM microphone data over an extended period of time sampled at a relatively high frequency. I don't want/need to access the data in real time, I just want to be able to periodically pull data in between experiments. However, I do realize that dual access to an SD card without physically replacing the card is not trivial. Do you have any other suggestions?
I think that my solution is going to be to use a beefy Micro SD card in the slot on the RPi and send the PDM data from the FPGA to the RPi via SPI. This will introduce a constant workload on the RPi, but power isn't a problem for this application. Someone please stop me if this sounds like a bad idea or if you think of a better one.