Processor delivers live rear-view video 0.5s from start-up
Article By : Vivek Nanda
Intersil's TW884x processors target rear-view camera applications with near-instant display boot-up and reliability in the face of SoC crashes.
Intersil, a subsidiary of Renesas Electronics Corp. since February 2017, has claimed it has the automotive industry's first full HD (1080p) LCD video processor that provides the reliability needed to ensure rear-view camera systems compliant with the U.S. Federal Motor Vehicle Safety Standard (FMVSS-111) for preventing injury or death caused by such accidents.
The TW8844 enables the migration from analog to digital camera systems and supports a variety of video interfaces and LCD panel resolutions up to full HD 1920 x 1080. The video processor with MIPI-CSI2 output and TW8845 video processor with BT.656 output exceed the requirements of the FMVSS-111 law displaying live video with graphics overlay in less than 0.5s after vehicle ignition.
The TW884x provide a rear-camera architecture to overcome the fast boot reliability issues. Today’s head units are prone to OS software freezes and hang-ups that display a frozen image or prevent the rear camera from displaying live video. With SoCs running increasingly complex operating systems software freezes and hang-ups are more common. The TW884x eliminates this problem by monitoring the SoC and camera output to determine if they are in a frozen or corrupted state. If the TW884x detects any issue it bypasses the SoC and instantly displays the rear-view camera video.
In an interview with EE Times India, Jonpaul S. Jandu senior marketing manager at Renesas' Intersil said, "If you just start the car the whole system has to boot up. And today they are running very complicated operating systems—Android Linux even some Windows. Depending on the processor and the OS it could take 5s or 6s to boot up.
"The TW8844 is basically a hardwired solution. We just have registers. So you set a few register settings it's firmware and then it goes by itself. It's not relying on a heavy software stack. We can boot-up sync to even an analog source and scale it and drive an LCD directly in less than half a second."
The TW884x series provides a rear-camera architecture to overcome the fast boot reliability issues, for instance, freezes or hang-ups, inherent with today’s more complex centre stack systems. It monitors the SoC and camera output to determine if they are in a frozen or corrupted state. If the TW884x detects any issue it bypasses the SoC and instantly displays the rearview camera video. "The bypass architecture essentially de-couples the video path from the rest of the navi system, making it easier to get the functional safety rating, which is called the ISO 26262," Jandu added.
Figure 1: System architecture. The EEPROM fast boot function enables fast boot with no MCU needed.
The story behind safety requirements
The fast boot-up and reliability requirements are mandated by the U.S. FMVSS-111 regulation for all new cars sold (in the United States) beginning May 2018. They were pushed by an American father who accidentally ran over his two-year-old son as he reversed his car. The father campaigned for a law that's now regulation taking effect 15 years after the tragic incident.
When asked to put this product in context of Asia, Jandu said, "The Japanese car makers bypass the SoC all the time. It didn't take a law for them to say they want that camera on all the time. In China, what we found is that video around the car like a birds-eye view is very popular. You don't need a law to say you want to see all around your car; people want it. So the car companies are putting it in anyway. When this law passed nearly 10 years ago, analysts asked me do you anticipate similar laws in Asia, Japan and Europe and I said 'Yeah.' But what happened was that this law got delayed in the U.S. and all these OEMs realised this such an easy thing to do and they put it everywhere. I haven't seen the legislation but I've seen it rolling out everywhere.
India catching up?
"The one market that was the slowest was India. I think they are just trying to keep the cars as cheap as possible. Now, Tata, Mahindra, Suzuki [Maruti], all those guys are putting this in more of the mid- and higher-end but it will trickle down to the low end. In the last one year, I'm getting a lot of inquiries from Indian OEMs for my video processor."
The TW8844 and TW8845 can be combined with Renesas’ R-Car SoC family as well as the ISL78302 dual LDO ISL78322 dual 2A/1.7A synchronous buck regulator and ISL78228 dual 800mA synchronous buck regulator to provide power rails for the TW884x SoC and other key components on the automotive infotainment system board.
The TW8844 video processor with MIPI-CSI2 output is available in a 14mm x 20mm 156-lead LQFP package and is priced at $10 in 1000-unit quantities. The TW8845 video processor with BT.656 output is available in a 14mm x 20mm 156-lead LQFP package and is priced at $9.50 in 1000-unit quantities.