vehicle today consists of several separate domains, including Infotainment, Advanced Driver Assistance System (ADAS) and control domains. Each uses different dedicated interfaces and pre-defined connectivity technologies. “The missing link in connecting those different domains has been a low-latency, high-speed bus,” said Tan. The single-pair gigabit Ethernet based on the 1000BASE-T1 spec can fill the gap, he explained.
Another place where the use of 1000BASE-T1 chips makes sense is in connecting multiple cameras inside a vehicle.
Tan said vehicles today use two types of camera connectivity – one for vision applications and another for machine analysis.
Typically, carmakers accept compressed video for the vision apps, but not where computer vision analysis is required. That’s why, for the latter, LVDS (Low-voltage differential signaling) is still the preferred connectivity for transferring uncompressed video data.
Because uncompressed HD video needs more than 100 Megabit per second, even the 100BASE-T1 solution, at 100Mbps, requires video compression. The result is image degradation, and latency caused by the compression algorithm could add latency, said Marvell, limiting applications for Ethernet.
In contrast, at 1 Gigabit per second, “little or no compression is required.” The 1000BASE-T1 chips can support higher quality image transport for machine vision, HD console and instrument cluster. Marvell’s 88Q2112, based on 1000BASE-T1 spec, enables the transport of uncompressed 720p30 camera video, and supports multiple [compressed] HD video streams with up to 4K resolution, said Tan.
Unlike LVDS that is a point-to-point serial connectivity, the automotive Gigabit Ethernet implemented in a module can handle multiple video streams from the growing number of cameras inside cars, Tan explained.
Marvell’s 88Q2112 chip, further, features “upgrade compatibility to support both 100Mbps and 1000Mbps single-pair Ethernet solutions, and can be used to aggregate multiple 100Mbps Ethernet domains.”
The third obvious spot to use the Gigabit Ethernet chip is the infotainment space, according to Tan. This is where MOST (Media Oriented Systems Transport) has dominated inside a car as a dedicated