Hello Mi Fans,
Welcome back to Mi Community Tech Class Session. In the previous Tech Class, you got all the information about LED Flash used in smartphones. In today's Tech Class, you will learn about eMMCs used in smartphones.
Mobile phones, particularly smartphones, has become an inevitable part of our day to life. It all began when a US Patent was issued in Kentucky for a wireless telephone in 1908. The earlier mobile phones ware used just for making calls, but it evolved into something great which can be used to achieve beyond what you can imagine 2 decades before.
Raw Flash and Managed Flash
Before going into eMMC in details. Let’s talk about storage solutions. As the capability of smartphone increased, the necessity of capable storage solution was inevitable. Before eMMC became leading in storage solution for mobile devices, there were raw NAND.
NOR and NAND are raw storage devices. The main difference between NAND and NOR is that NOR allows random access, doesn’t need error correction as well as has higher cost-per-bit. NAND on the other side can only be read in pages, some bits in a page may be wrong and need to be corrected by an error correction mechanism. This technology was used earlier and it is bulky as well in a design perspective.
eMMC Flash combines NAND memory with a built-in controller that handles most of the things you have to take care of when dealing with NAND flash. eMMC is also called managed NAND.
What is eMMC?
The term eMMC is short for "embedded Multi-Media Controller”. The eMMC solution consists of at least three components - the MMC (multimedia card) interface, the flash memory, and the flash memory controller.
SanDisk 64 Gb iNAND eMMC
Today’s embedded applications such as digital cameras, smartphones, and tablets almost always store their content on flash memory. In the past, this has required a dedicated controller to manage the reading and writing of data, driven by the application CPU. However, as semiconductor technology has evolved to allow vastly increased storage density, it has become inefficient for the controller to manage these functions from outside the flash memory. Hence, eMMC was developed as a standardized method for bundling the controller into the flash.
As eMMC has improved, the standard has also provisioned for features such as secure erase and trim and high-priority interrupt to meet the demand for high performance and security. So while the eMMC standard was created to improve data rates and throughputs for high-density chips designed to store high-resolution video, newer generations are doing more for more applications, and each generation of the standard will include additional new features for a richer end-user experience.
What made it so special?
Due to a wide variety of smartphone innovations, memory consuming applications increased and old NAND architectures became inefficient. It’s rather amazing that the memory solution for almost every mobile application over the past decade is something that very few people beyond design engineers have ever heard about. Users sometimes ignore and don’t dig deeper on how the device memory performs. eMMC or embedded multimedia card memory is a low-cost, high-performance electronic invention which is one of the largest selling memories in the world and has been for some time.
The eMMC architecture integrating the flash memory controller in the same package simplifies the application interface design and frees the host processor from low-level flash memory management. This benefits product developers by simplifying the non-volatile memory interface design and qualification process – resulting in a reduction in time-to-market as well as facilitating support for future flash device offerings.
Generic eMMC architecture
eMMC eliminates the need to develop interface software for all types of NAND memory by integrating the embedded controller into the memory chip and providing an easy-to-use memory solutions package for high-speed data transmissions by devices, such as mobile phones. It also eliminates the need for a memory expansion slot by stacking several memory functions vertically, resulting in a very small footprint for the memory devices.
Who makes eMMC?
Following are the main eMMC manufacturers around the world. Among these Samsung leads the R&D and inventing next generation eMMC.
Now you may think why can’t we use SSD instead of eMMC. Despite both containing a type of NAND memory, SSDs and eMMC storage are quite different.
Samsung SEC 449
The current standard for eMMC storage is 5.1, which can effectively deliver transfer speeds of up to about 400MB/s. That's not necessarily a slow speed, as SATA SSDs will top out around the same.
However, it's not just the overall transfer rate that determines how a device's performance will be affected. eMMC storage usually operates with fewer memory gates than an SSD, meaning it can still deliver at the same speed, just not at the same volume.
Think of it like a road — the more lanes, the more cars you can move at a time. eMMC is a single lane each way, while an SSD is a multi-lane highway. You'll go the same speed on either one, but the on-ramp to get onto the road won't be nearly as slow on the highway. SSD can be a bit costly than eMMC which makes using eMMC is more convenient for a smartphone since this so-called “multi-lane data transfer” comes in the picture if the device is a laptop. But its future it may come to a point that SSD or some advanced technology can take over eMMC resulting in faster internal data transfer in mobile devices.
In case you missed previous threads:
Chapter 64: All About Smartphone LED Flash
In order to fulfill the basic functions of our service, the user hereby agrees to allow Xiaomi to collect, process and use personal information which shall include but not be limited to written threads, pictures, comments, replies in the Mi Community, and relevant data types listed in Xiaomi's Private Policy. By selecting "Agree", you agree to Xiaomi's Private Policy and Content Policy .