I'm currently working on designing a new board with a Cyclone V HPS. I would like to use a 16GB eMMC device for storage of the application code, as well as the FPGA configuration. I am looking at two devices right now, but they appear the have an extra "DS" (Data Strobe) pin. As I compare this to one of the demo boards I have this pin is not present.The chips I'm considering are MTFC16GAKAENA-4M IT and EMMC16G-W525-X01U. My question is: what should I do with this pin? I have looked in the data sheets and other documents online and can't seem to find an explanation of this newly added pin to the eMMC standard. Thanks, Mike
If I am not mistaken, the Data Strobe pin is added in in eMMC 5.0 specification for HS400 mode. However, the SD/MMC controller in Cyclone V only supports eMMC 4.41 and up to 25Mbps (yep, that's slow). In this case you should refer to the eMMC handbook to see if there is any mention on what to do when HS400 is not used.