One could argue that camera has been the most fascinating feature of smart phones in recent years. The latest camera phones are capable of not only capturing minute details with multi-mega pixels, but also sensing the presence of various objects. MIPI CSI-2 (Camera Serial Interface) is a high-bandwidth interface between a camera and a host processor. MIPI CSI-2 v1.1 got introduced in 2011 to fulfill the basic camera requirements of mobile applications. Next generation MIPI CSI-2 v2.0 and v2.1 have evolved to meet the requirements of emerging imaging and vision applications like wearables, IoT, drones, automotive, and security surveillance beyond smart phones. Read our previous blog to know more about MIPI CSI-2 v2.0: Emerging Applications in IoT, Drones and Automotive. The new features of MIPI CSI-2 v2.1 are outlined below:
- CCI upgradation: CCI (Camera Control Interface) is upgraded w.r.t I2C (Inter-Integrated Circuit) as well as I3C (Improved Inter-Integrated Circuit) interfaces.
- Dropped frame synchronization: MIPI CSI-2 v2.1 takes care of 16-bit frame number behavior when a frame of the same virtual channel is not transmitted due to some erroneous situation.
- Simplifies LRTE (Latency Reduction and Transport Efficiency): Simplifies and resolves the open points missing in the earlier MIPI CSI-2 v2.0 specification such as requirement of number of spacer words, requirement of spacer words w.r.t. each PHY lane, etc. Correct PPI TX/RX signal reference is also provided.
- Generic 8-bit long packet data types: Introduces new generic 8-bit long packet data types (4 in number) by utilizing few RESERVED data types. This is implemented to utilize these data types as user specific data type packets, applicable for both automotive and IoT applications.
- CSI-2 over MIPI C-PHY ALP and PPI: Provides guidance for implementing MIPI C-PHY ALP (Alternate Low-Power) when MIPI CSI-2 is used as a protocol layer. It simplifies the concepts of ALP mode and legacy LP mode, and also explains about transmission and reception of ALP commands via PPI signals.