What is MIPI
MIPI is the abbreviation of Mobile Industry Processor Interface. The MIPI protocol is proposed to solve the contradiction between the growing high-bandwidth requirements of high-definition image (video) transmission and the low rate of traditional interfaces, while providing a unified standard for the entire industry, thereby shortening the product development cycle and enhancing the compatibility of products between different manufacturers. In other words, the MIPI protocol is an open standard and a specification initiated by the MIPI Alliance for mobile application processors.
MIPI was originally proposed by Intel, Motorola, Nokia, NXP, Samsung, ST and TI (current members of the alliance board of directors). Later, with the participation of big names such as ARM, Apple, Lattice, ADI, TOSHIBA, Cadence, Dell, Google, Hisilicon, etc., the MIPI protocol has gradually been recognized and accepted by the industry. Nowadays, MIPI protocol is widely used in various embedded image devices, such as smart phones, VR, smart TVs, smart wearable devices, ADAS systems, etc.
When MIPI protocol was first proposed, there were two main applications, CSI (Camera Serial Interface) and DSI (Display Serial Interface), which share a physical layer protocol D-PHY. At the same time, the DSI protocol also involves some other top-level protocols, such as DPI (Display Pixel Interface), DBI (Display Bus Interface) and DCS (Display Command Set). Among them, the CSI protocol is currently widely used in its second version – CSI-2, which aims to provide a high-speed serial interface between high-definition cameras and application processors. For example, the CSI protocol is used between the camera and the CPU in current smart phones. The DSI protocol aims to provide a high-speed serial interface between the application processor and the display device. For example, the DSI is used between the CPU and the LCD (liquid crystal screen) in smart phones.
However, with the development of the MIPI Alliance, not only CSI and DSI are constantly updated, but new physical layer protocols have also been proposed, such as M-PHY and C-PHY. Currently, D-PHY has been updated to v1.2, M-PHY has been updated to v3.1, and C-PHY has been updated to v1.0. The main differences between the three protocols are as follows:
Taking a smartphone (or multimedia system) as an example, the main application directions of the three physical layers are shown in the following figure:
