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I will be using the following FPGA https://store.digilentinc.com/nexys-video-artix-7-fpga-trainer-board-for-multimedia-applications/ I have a module who has 16 std_logic_vector (13 downto 0) outputs The values of these outputs are changing every 50 Mhz on every rising edge of my FPGA_clock. I want to store these datas on an SD CARD and be able to read back the data out of the SD Card. But i don't know if it is possible to read and write on the SD CARD using the signals: VDD DAT2 DAT1 CMD CLK DAT3 DAT0 CARD_DETECT Is there any document that explains how to control these signals to write and read on a SD CARD via an FPGA? Thank you for your helpenter image description here

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    \$\begingroup\$ You can find the SD and UHS specs at sdcard.org/downloads/pls/index.html It sounds like you're looking for a phy level interface block, and probably a higher level driver or state machine. Is that accurate? I believe the Phy is essentially just a multi-bit SPI, but the spec would say for certain. \$\endgroup\$ – pscheidler Mar 28 '18 at 15:27
  • \$\begingroup\$ Thank you for the link, i still don't know what is a phy level interface block. All i want to do is write the data on the SD card and then after i stored all the data on the SD card i want the FPGA to be able to access the data an read it back \$\endgroup\$ – the dude Mar 28 '18 at 16:24
  • \$\begingroup\$ The Digilent doc says "For information on implementing the SD card controller, refer to the SD card specification available at www.sdcard.org". I suggest that should be your first step. The doc says the interface can support full SD speeds, so I would say yes, you can write and read from the SD card using your FPGA. \$\endgroup\$ – Catsunami Mar 28 '18 at 17:44
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    \$\begingroup\$ Your comments indicate you've not come to grips with how low-level the interaction with the SD card is that you'll have to implement! The card doesn't "just write data". It needs to be initialized, you need to read out the memory structure, and need to implement all the logic that takes care of the card when writing stuff to it - that can take variable time, might involve checksums, has to happen only when the card is ready, has to happen in specific chunk sizes... An FPGA is not a computer with dedicated SD card interface hardware and an operating system with a driver and a file system! \$\endgroup\$ – Marcus Müller Mar 29 '18 at 0:50
  • \$\begingroup\$ Thank you in fact i thought that we could access an SD card as we access a BRAM \$\endgroup\$ – the dude Mar 29 '18 at 22:14

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