Design Considerations for UFS and eMMC


You’re an SoC design engineer, or engineering manager, just tasked with designing the next generation SoC.  The SoC would power the new and exciting phone / tablet / wear-able gizmo, and obviously needs some (actually, a lot of) flash storage.  Where do you start?  What are the challenges you’re about to face?  How do you finish the design on time?  Read on and you’ll get all those questions answered.Compliance to industry standards for mobile storage Currently, the de-facto standard is eMMC.  Introduced by JEDEC in 2007, and has evolved at accelerating rate.  eMMC 4.51 spec was published in June 2012.  eMMC 5.0 spec is near completion (as of Aug. 2013). A new emerging standard, nick-named “embedded SSD” or “SSD for tablets and smart phones”, is UFS (Universal Flash Storage).  Version 1.1 of the spec was published in June 2012.  Version 2.0 is expected shortly. The challenge for engineers is to keep up with all these spec changes in a faster pace. Backward compatibility Compliance to all of the latest specifications, from different standards, also means backward compatibility to earlier versions.  Earlier specification versions include:

  • eMMC 4.3, 4.4, 4.5
  • UFS version 1.0, 1.1
  • UniPro (link layer for UFS) 1.40, 1.41
  • M-PHY (physical layer for UFS) 1.0, 2.0

The challenge is to implement and test all spec version combinations. Hardware Validation and Inter-operability Verifying operation with multiple devices from different vendors is very important.  Your new SoC should work with multiple eMMC or UFS devices, offered by various vendors. The challenge is to test your design with silicon from other parties, especially for new standards, such as UFS 2.0.  Is there a solution for the challenges presented? A Total IP Solution is required to guarantee compliance to the specs, ensure backward compatibility, and enable Inter-operability and system validation. Arasan follows this approach, to ensure their UFS and eMMC IP products are validated, and available before the next SoC design cycle, to help you with fast time to market. View the rest of the whitepaper here.