WEDNESDAY 30 OCTOBER 2019

Future-Proofing Connectivity with MIPI DSI

The MIPI interface, already established as an industry-leading standard for high-definition smartphone and mobile technology, is fast becoming the next-generation interface in the broadcast sector. Matej Gutman, Embedded Engineering Manager at Densitron looks at how MIPI DSI is having such an impact and the significant benefits it brings.

The widespread growth of premium quality, high-resolution graphical display technology in mobile communications devices is having a significant effect on many related mobile-influenced applications. This is particularly the case in the broadcast sector, where operators are now looking to achieve the same high-quality graphic interface and user experience that they have come to expect in their everyday communications devices. As design engineers continue to borrow from the smartphone and tablet sector, the desire amongst users of audio monitoring equipment, rack-mounted mixing decks and editing systems for more effective, content-rich and efficient display technology will only increase. In turn, this is putting a huge strain on the interface connections that have to cope with these increased transmission demands. 

Existing traditional interface specifications are now struggling to cope with the extra transmission burdens required to support these advanced display technologies. Utilising additional data channels and increasing the speed of transmission to host higher resolution is adding to an already overloaded pin count and increasing EMI (electromagnetic Interference) susceptibility and radiation.

Typically, an RGB parallel interface has a minimum of a 28-pin connection for handling 24-bit true colour graphics. While this connection offers a relatively straightforward solution in terms of design, configuration and troubleshooting, it simply doesn’t have the scope or capacity to increase pin count further or enhance speed without adding bulk and becoming more susceptible to EMI. This led the way for the introduction of LVDS (Low Voltage Differential Signalling) which uses a differential serial communications protocol capable of operating at higher speeds. LVDS has certainly been able to bridge the gap for some time as an alternative interface protocol for display transmissions and has delivered certain benefits in terms of reduced EMI while offering the power to transmit higher-definition video and graphics. However, as advances in display technologies continue to grow, so do the requirements of the interface to facilitate these enhancements. And, with LVDS reaching maturity, there is little flexibility for future technological advancement to handle the evolution of the very high-definition 4k graphical displays.

This is where the MIPI (Mobile Industry Processor Interface) Alliance has come into its own by developing a series of compelling interface specifications that are growing in popularity. The MIPI Display Serial Interface (MIPI DSI) protocol is set to become the next-generation standard for display technology. MIPI is suited to conserving power for optimum battery consumption by incorporating low-power and high-speed modes into its specification. In addition, by using a bidirectional data lane, extra settings such as gamma curve and brightness can be set without introducing additional communication channels. This reduces the burden for software engineers when introducing new displays and allows for other specifications to interconnect components, from camera and imaging components to audio devices and sensors.

Founded in 2003, the MIPI Alliance has grown in strength and stature from four original founding members to over 280 partner organisations, including the world’s leading electronics companies. The key principle of the MIPI Alliance focuses on the development and consolidation of interface standards and promoting and encouraging the use of hardware and software interfaces that simplify the integration of components across a wide span of mobile and mobile-influenced industry applications.

The MIPI DSI protocol is a versatile, high-speed interface. Developed specifically to handle premium quality, content-rich displays in smartphones, tablets and laptops, which is now finding its place as the interface of choice for a range of mobile-influenced applications. These include auto infotainment systems, audio mixing decks, production suites and other rack-mount monitoring applications. Using a reduced number of wires, typically just six for colour transmission, and operating at a lower power consumption to conserve battery life, the MIPI DSI interface can handle high-speed signals for driving ultra-high resolution, premium performance displays from full HD to 4K and beyond. In addition, by utilising the principle of serial communication and with its simplified pin count, the MIPI DSI interface benefits from a significant reduction in electrical noise generated on the bus and therefore limited EMI emissions and susceptibility. 

The latest version of the MIPI DSI specification is the forward-looking MIPI DSI-2 V1.0, a high-speed interface that offers scalability and support for both D-PHY and C-PHY. This offers designers even greater flexibility to support the integration of a range of the latest high-performing display technologies into a host of broadcast applications depending on the desired configuration needed to meet the market’s current and future needs.
With the backing of the MIPI Alliance, its interface standards and protocols have become well-established in mobile applications and are now highly respected and trusted throughout the electronics community, which is looking to implement the MIPI protocols into a wider range of related applications.

There is also the added confidence amongst design engineers and manufacturers that MIPI interface standards are widely supported by ongoing development and constant advancement. Take, for example, the anticipated ‘MIPI Touch’ protocol for the introduction of touch technology as evidence of innovation and the Alliance’s commitment to future technology development.

There has never been a greater selection of advanced display technology for the broadcast sector to use to enhance the performance, user experience, look and feel of audio, production and editing equipment. However, when integrating these new solutions into equipment and devices, it is just as important that design engineers and product developers consider the capabilities of the interface. Not only is it vital that these connections serve current market requirements, but they also have to be able to adapt and cope with ongoing future demands. 

The MIPI DSI interface has, without a doubt, made a significant impact on the mobile sector to date. And its high performance, reduced pin count and lower power consumption can only be good news when looking to integrate premium quality displays into broadcast solutions and ensure they are next-generation ready.