Latest and forthcoming CMOS image sensors surpass 10M pixels, and output video at 30 and even 60 fps.
This development requires high bandwidth between the camera and the application processor.
For example, a commercially available 4068x3456 30 fps camera outputs an average of over 5Gbps,
which requires 4 DPHY lanes at more than 1.25Gbp – more the original 1Gpbs of MIPI DPHY 1.0,
but still manageable by the extended 1.5Gbps of the latest DPHY spec.
However, when the same or similar camera is introduced with 60fps, over 10Gbps will be required,
and 4 lanes will not suffice.
MIPI’s forthcoming new set of standards (CSI3 over UNIPRO and MPHY) will offer higher bandwidth.
However, until those standards are available, camera vendors are looking for ways to increase CSI2 speed.
Among others, extension of the CSI2 standard to 8 data lanes, with one or two clock lanes, are introduced.
Application processor vendors also face speed issues. Processing frames of 16 million pixel at 60 fps
require the processing of 1G pixel per second. As employing a 1GHz clock is not desirable, the trend is to
process more than one pixel in each clock cycle.
VLSI Plus' SVRPlus-CSI2-I IP core is designed to support those trends, and, at the same time, work with a
relatively slow clock rate, processing several pixels per clock.
The SVRPlus-CSI2-I has an internal 64-bit bus. With this bus width, 10Gbps can be handled by a reasonable 167MHz clock.
The output path of the SVRPlus-CSI2-I can handle 1, 2 or 4 pixels in parallel. Image sensors which generate, for example,
12M * 60 fps = 720M pixels per second, can be handled by the SVRPlus-CSI2-I driven by a 180MHz clock, if the
PARALLEL_PIXELS compilation switch is set to 4.
The SVRPlus-CSI2-I can handle up to 8 data lanes, with one or two clock lanes, and at up to 1.5Gbps per lane.
If extended CSI2 is not required, the customer can save gate count and off-FPGA circuits by setting the EIGHT_LANES
compilation switch to NO.