MADISON, Wis.—Marvell has won the race to a Gigabit automotive Ethernet PHY transceiver chip that can be shown off to car OEMs and Tier Ones. Called 88Q2112, it is compliant with the draft IEEE 802.3bp 1000BASE-T1 standard.
The automotive industry has only begun to embrace the automotive Ethernet standard. The technology called “BroadR-Reach,” defined by OPEN Alliance industry group and designed to enable 100 Megabit per second data distribution inside the car, is getting designed into some cars. Meanwhile, the IEEE is turning the BroadR-Reach technology—originally developed by Broadcom—into a formal IEEE standard called 100BASE-T1.
Unlike Broadcom or NXP, though, Marvell isn’t a member of the OPEN Alliance, and the company is yet to launch commercial 100Mbps automotive Ethernet products.
Marvell’s pre-emptive move to push its gigabit Ethernet solution based on IEEE’s draft 1000BASE-T1 spec appears to suggest that the company is planning to leapfrog 100BASE-T1.
That, however, isn’t Marvell’s intention at all, stressed Alexander Tan, Marvell’s automotive solutions group product line manager. Rather, he said, “We see 100BASE-T1 and 1000BASE-T1 are complementary to each other. We want to offer to architects at carmakers and Tier Ones a full portfolio of automotive Ethernet solutions.”
The goal is to promote an automotive Ethernet that allows multiple in-vehicle systems to simultaneously access information over unshielded single twisted pair cable, he explained. Both IEEE standards—100BASE-T1 and 1000BASE-T1—use single-pair of wires, reducing weight and cost.
Marvell will demonstrate both single-pair automotive Ethernet solutions—one based on the draft 100BASE-T1 specification and another on the draft 1000BASE-T1—at a show called “the IEEE Standards Association (IEEE-SA) Ethernet & IP @ Automotive Technology Day 2015” in Japan later this month.
Kevin Mak, senior analyst at Strategy Analytics, described Marvell’s new gigabit Ethernet chip as “aiming to lower cost for gigabit-speed Ethernet, and, in turn, be an enabling technology for autonomous driving developments.”
He added, “Marvell will be first to market, but rivals will also be launching their devices in due course.”
Where inside a car will 1000BASE-T1 go?
Marvell sees a backplane of the vehicle network as one of the first places where 1000BASE-T1 will find its home.
Tan explained that a 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.”
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