DisplayPort Alt Mode is an extension protocol for the USB Type-C interface that allows simultaneous transmission of video, data and power over a single interface. In industrial scenarios, this technology significantly simplifies the device connectivity architecture. In some industrial display devices, where a traditional solution would require separate HDMI, USB, and power cables to connect a PLC to an HMI touchscreen, DisplayPort Alt Mode allows for 4K video transmission, control command interaction, and 60W of power with a single Type-C cable. This integrated solution reduces the number of device interfaces and the complexity of production line wiring.
Technical challenges of DisplayPort Alt Mode
Cross-platform driver development needs to address the synergy between the USB PD protocol, which is responsible for power negotiation and requires the driver to switch from 5V to 20V within 300ms, and the DisplayPort protocol, which manages the bandwidth allocation of the video stream. In medical endoscopy system, if the delay of PD protocol negotiation is more than 50ms, it will lead to unstable power supply of the endoscopy camera, and then the driver needs to intervene actively to retry the power supply handshake process. In addition, Windows and Linux systems have different access methods to Type-C controllers, and developers need to implement protocol stack compatibility layers for the WDF framework and Type-C subsystems respectively.
Design Requirements
Industrial sites have stringent requirements for hot-plugging and anti-interference capabilities, and the HPD (Hot Plug Detection) signal in the DisplayPort Alt Mode standard is susceptible to electromagnetic interference in harsh environments, leading to false triggering of display disconnection. The control system of an offshore drilling platform effectively eliminates the problem of misjudgment caused by surge by adding a 50ms signal filtering algorithm in the driver layer.The stability of EDID (Extended Display Identification Data) is also critical, and the driver needs to have built-in EDID caching mechanism when different brands of displays are frequently replaced in the production line. For example, automobile manufacturing workshop by pre-storing the 2560×1440 resolution parameters of Samsung/LG display, so that the resolution adaptation time when switching equipment from 3 seconds to 0.5 seconds.
Application Scenario
In the rail transportation dispatching system, DisplayPort Alt Mode driver realizes multi-screen cooperative control. A high-speed rail console drives two 4K monitors and 12 RS485 devices through a single Type-C interface, and the driver adopts a dynamic bandwidth allocation strategy: when the peak transmission of scheduling commands arrives, it automatically reduces the USB3.0 bandwidth from 10Gbps to 5Gbps to prioritize and guarantee the continuity of monitoring video streams. The in-vehicle infotainment system, on the other hand, faces space constraints. By optimizing the HPD response algorithm, the center driver of the Azalea ET7 model improves the recognition speed of the rear entertainment unit by 62%, while maintaining a stable output of the main screen at 2560×1600 60Hz.
Golden Margins –Entire Range of Touchscreen Products
We hope you found these touchscreen or panel PC fundamentals informative. Goldenmargins offers a broad selection of Industrial Touchscreen Monitors and Touch Panel PCs in various sizes and configurations, including medical touch screens, sunlight-readable touch screens, open-frame touch screens, and waterproof touch panels, as well as other unique touch screen or panel PC designs. You can learn more about our services HERE or by calling us at +86 755 23191996 or sales@goldenmargins.com
