SD Card V.4.1 & UHS-II PHY

SD 4.1 Total Solution - Arasan Chip Systems, Inc. (Arasan)

To meet the ever increasing data transfer rate in high end applications, such as professional broadcasting transmission or advanced high resolution display, the SD 4.1 specification calls out the maximum performance of 1.56 Gbps at UHS-II full duplex mode per lane or half duplex UHS-II at 3.16 Gbps. In real applications, due to the system overhead and different SD 4.1 device controller designs, the actual measured performance can vary dramatically from system to system. With the newly introduced ADMA 3, the OS driver is now able to issue multiple read or multiple write commands at once, without having to wait for the SD controller to complete one command at a time. Once the SD host controller has collected multiple commands, it will then manage and complete them without intervention from the host software drive. Thus, the UHS-II 1.56 Gbps interface can be more effectively utilized and maximize the system throughput. This feature can be very useful when running multithreaded applications where multiple applications are constantly updating their status or swapping their contents by writing or reading small chunk of data to or from the memory card.