Version 5.0 Specification for M-PHY
23-Jun-2021
Copyright © 2008−2021 MIPI Alliance, Inc. 1
All rights reserved.
Confidential
1 Introduction
This document describes a serial interface technology with high bandwidth capabilities, which is particularly 1
developed for mobile applications to obtain low pin count combined with very good power efficiency. It is 2
targeted to be suitable for multiple protocols, including UniPro
SM
and DigRF
SM
v4, and for a wide range of 3
applications. 4
The M-PHY Specification features the following aspects: 5
• BURST mode operation for improved power efficiency 6
• Multiple transmission modes with different bit-signaling and clocking schemes intended for different 7
bandwidth ranges to enable better power efficiency over a huge range of data rates 8
• Multiple transmission speed ranges and rates per BURST mode to further scale bandwidth to 9
application needs, and for mitigation of interference problems. Rates for high-speed mode are fixed, for 10
low-speed modes they are flexible within ranges 11
• Multiple power saving modes, where power consumption can be traded-off against recovery time 12
• Symbol coding (8b10b) for spectral conditioning, clock recovery, and in-band control options for both 13
PHY and Protocol Layer. 14
• Clocking: designed to exploit the benefits of a shared reference clock 15
• Distance: optimized for short interconnect (<10 cm) 16
• Configurability: differences in supported functionality (to reduce cost) and tune for best performance 17
(implementation) without hampering interoperability 18
• Debuggability: receiver has optional eye monitor function 19
1.1 Scope
This document specifies unidirectional LANEs and its individual parts, as building blocks for composition 20
of a dual-simplex LINK by application protocols. An M-PHY implementation allows one or more LANEs in 21
each direction, allows differences in optional functionality between LANEs, allows different momentary 22
operating modes between LANEs, and allows asymmetry in amount of LANEs and LANE properties for the 23
two directions of the dual-simplex LINK. Protocols applying M-PHY technology may have different LANE 24
constraints, and choose different operation control, or data striping and merging solutions. Therefore, this 25
document provides the features to enable LINK composition, but does not specify how multiple transmitters 26
and receivers are combined into a PHY-unit for a certain LINK composition. Each LANE has its own 27
interface to the Protocol Layer. 28
A MODULE can disclose its capabilities, and contains several configurable parameters in order to allow 29
differentiation on supported functionality and tune for best performance without hampering interoperability. 30
Therefore, protocols need to support some configuration mechanism to determine and define the operational 31
settings. Most flexible is an auto-discovery negotiation protocol to determine the commonly-supported 32
settings of the Physical Layer which are most desirable for running the application. M-PHY supports this, 33
but does not include the configuration protocol itself. Alternatively, the protocol may directly program the 34
required settings if there is predetermined higher system knowledge about which MODULEs are present at 35
both ends of that LINK. 36
The M-PHY specification shall always be used in combination with a higher layer MIPI specification that 37
references this specification. Any other use of the M-PHY specification is strictly prohibited, unless approved 38
in advance by the MIPI Board of Directors. 39
1.2 Purpose
Mobile devices face increasing bandwidth demands for each of its functions as well as an increase of the 40
number of functions integrated into the system. This requires wide bandwidth, low-pin count (serial) and 41
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