| M-PHY | |
| Fullname: | MIPI M-PHY |
| Invent-Date: | 2011 |
| Invent-Name: | MIPI Alliance |
| Replaces: | D-PHY |
| Width: | 1–4 lanes, w/adaptive discovery (depending on higher-level protocol) |
| Speed: | up to 11.6 Gbit/s per data lane |
| Style: | serial, embedded clock |
| External: | yes, with optical media converter |
| Website: | https://mipi.org/specifications/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.[1] The specification's details are proprietary to MIPI member organizations, but a substantial body of knowledge can be assembled from open sources. A number of industry standard settings bodies have incorporated M-PHY into their specifications including Mobile PCI Express,[2] [3] [4] [5] [6] [7] [8] Universal Flash Storage,[9] [10] [11] and as the physical layer for SuperSpeed InterChip USB.[12] [13] [14] [15] [16] [17]
To support high speed, M-PHY is generally transmitted using differential signaling over impedance controlled traces between components. When use on a single circuit card, the use of electrical termination may be optional. Options to extend its range could include operation over a short flexible flat cable, and M-PHY was designed to support optical media converters allowing extended distance between transmitters and receivers, and reducing concerns with electromagnetic interference.[15]
M-PHY (like its predecessor D-PHY) is intended to be used in high-speed point-to-point communications, for example video Camera Serial Interfaces. The CSI-2 interface was based on D-PHY (or C-PHY), while the newer CSI-3 interface is based on M-PHY. M-PHY was designed to supplant D-PHY in many applications, but this is expected to take a number of years.
The M-PHY the physical layer is also used in a number of different high-speed emergent industry standards, DigRF (High speed radio interface), MIPI LLI (Low latency memory interconnect for multi-processors systems), and one possible physical layer for the UniPro protocol stack.
M-PHY supports a scalable variety of signaling speeds, ranging from 10 kbit/s to over 11.6 Gbit/s per lane. This is accomplished using two different major signaling/speed modes, a simple low-speed (using PWM) mode and high speed (using 8b10b).[18] Communications goes on in bursts, and the design of both high-speed and low-speed forms allows for extended periods of idle communications at low-power, making the design particularly suitable for mobile devices.
Within each signaling method, a number of standard speeds, known as "gears", is defined, with the expectation that additional gears will be defined in future versions of the standard.[19]