The Camera Serial Interface (CSI) is a specification of the

Mobile Industry Processor Interface MIPI Alliance is a global business alliance that develops technical specifications for the mobile ecosystem, particularly smart phones but including mobile-influenced industries. MIPI was founded in 2003 by ARM, Intel, Nokia, Samsung, STMicroele ...

(MIPI) Alliance. It defines an interface between a

camera A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...

and a host processor. The latest active interface specifications are CSI-2 v3.0, CSI-3 v1.1 and CCS v1.0 which were released in 2019, 2014 and 2017 respectively.

Standards

CSI-1

CSI-1 was the original standard MIPI interface for cameras. It emerged as an architecture to define the interface between a camera and a host processor. Its successors were MIPI CSI-2 and MIPI CSI-3, two standards that are still evolving.

CSI-2

The MIPI CSI-2 v1.0 specification was released in 2005. It uses either D-PHY or C-PHY (Both standards are set by the MIPI Alliance) as a physical layer option. The protocol is divided into the following layers: # Physical Layer (C-PHY/D-PHY) # Lane Merger Layer. # Low Level Protocol Layer. # Pixel to Byte Conversion Layer # Application Layer In April 2017, the CSI-2 v2.0 specification was released. CSI-2 v2.0 brought support for RAW-16 and RAW-20 color depth, increase virtual channels from 4 to 32, Latency Reduction and Transport Efficiency (LRTE), Differential Pulse-Code Modulation (DPCM) compression and scrambling to reduce

Power Spectral Density The power spectrum S_(f) of a time series x(t) describes the distribution of power into frequency components composing that signal. According to Fourier analysis, any physical signal can be decomposed into a number of discrete frequencies, o ...

. In September 2019, the CSI-2 v3.0 specification was released. CSI-2 v3.0 introduced Unified Serial Link (USL), Smart Region of Interest (SROI), End-of-Transmission Short Packet (EoTp) and support for RAW-24 color depth.

CSI-3

MIPI CSI-3 is a high-speed, bidirectional protocol primarily intended for image and video transmission between cameras and hosts within a multi-layered, peer-to-peer,

UniPro UniPro (or Unified Protocol) is a high-speed interface technology for interconnecting integrated circuits in mobile and mobile-influenced electronics. The various versions of the UniPro protocol are created within the MIPI Alliance (Mobile Industr ...

-based

M-PHY M-PHY is a high speed data communications physical layer protocol standard developed by the MIPI Alliance, PHY Working group, and targeted at the needs of mobile multimedia devices. The specification's details are proprietary to MIPI member organ ...

device network. It was originally released in 2012 and got re-released in version 1.1 in 2014.

Camera Command Set (CCS)

The Camera Command Set (CCS) v1.0 specification was released on November 30, 2017. CCS defines a standard set of functionalities for controlling image sensors using CSI-2.

Technology & speeds

For

EMI EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British transnational conglomerate founded in March 1931 in London. At the time of its break-up in 201 ...

reasons the system designer can select between two different clock rates (a and b) in each of the M-PHY speed levels.Understanding MIPI Alliance Interface Specifications
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References

MIPI Alliance standards Serial buses {{standard-stub