Winbond Electronic’s latest NOR flash memory device aimed at the automotive market shows that robust security is now table stakes in the industry.
What are the benefits of NOR Flash?
The primary benefit to using NOR is that it delivers far better read performance than a comparable NAND device. By way of comparison, a NAND multi-level cell (MLC) flash device can be expected to read data at about 20.5 MBps (megabytes per second), while comparable NOR MLC flash devices have benchmarked read rates of 61.5 MBps.
At the same time though, NOR's write and erase operations are much slower than NAND storage. A NAND MLC device might write data at 3.2 MBps, while a comparable NOR MLC device is only able to write data at about 0.47 MBps. Additionally, the size of its individual cells limit overall storage capacity.
NOR's limitations combined with the fact that NOR delivers blazing-fast read performance means NOR is best suited to use cases in which a limited amount of data needs to be stored and in which most of the storage IO (input/output) will be read IOPS (I/O per second).
This is why NOR flash is so commonly used in consumer devices such as tablets and smartphones. Those devices tend to have relatively lightweight OSes that can easily fit within NOR's limited capacity. NOR's characteristically fast read performance enables the OS to be booted far more quickly than would be possible if the device's OS were stored on NAND storage.
The company recently unveiled its TrustME W77T Secure Flash family, a secure flash compliant product with several key automotive standards, including ISO26262 ASIL-D Ready, ISO21434 Certified, UNECE WP.29 and TISAX.
In a briefing with EE Times, Jun Kawaguchi, a marketing executive at Winbond, said the company’s TrustME secure flash is designed to meet the demands of emerging automotive applications, such as software-defined vehicles (SDVs), while balancing performance and security protection required for connected and autonomous vehicles.
Kawaguchi said the high performance is delivered using an Octal/xSPI interface, enabling the device to operate at a 200MHz double transfer rate (DTR), while delivering a read bandwidth of up to 400MB/s—making it ideal for automotive SoC designs that require fast boot times and high-performance processing capabilities.
Kawaguchi said the trend in the automotive market toward high performance has meant that Octal/xSPI interfaces are now replacing Quad-SPI, which used to be sufficient for bootup sequences in automotive applications. “There’s an increased demand for fast boot, particularly at that 200-megahertz bandwidth,” he said.
Just as important are TrustME’s security capabilities, Kawaguchi added. “We’ve seen that the security requirements are increasing recently, particularly because there’s been a lot of supply chain penetration.” Combine this with hacking-type incidents, he said, and Winbond is seeing increased interest in secure solutions.
Kawaguchi explained that automotive security requirements are almost like insurance in that OEMs ask for it and do not want to pay extra for secure functions. This is especially true in the U.S. market, he said, where there is both a cost sensitivity as well as cybersecurity requirements and standards, such as ISO/SAE 21434.
Among TrustME’s many security features are post-quantum cryptography capabilities for its security engine, NIST 800-193 compliant firmware resiliency, ISO21434, FIPS 140-3 certification and ISO26262 Functional Safety requirements. Code and data protection features make it especially difficult for hackers to tamper with the device, Kawaguchi added, and like all Winbond secure flash devices, TrustME employs stringent authentication protocols.
He said adding security while maintaining performance is an important consideration. “We operate at pretty much a full speed, which is 200 megahertz, which is quite fast.”
When it comes to typical use cases, secure functions will include authentication, encryption and decryption in one portion, but those functions are not always turned on, Kawaguchi said. “You want to make sure that the system is authenticated and then you turn off the security and boom, you’re running full speed.”
NOR flash is well suited for the changes in automotive semiconductor content that are the result of SDVs, Kawaguchi added, which creates opportunities for Winbond as vehicles will come with a wide range of capabilities that will require more memory including NOR flash—even if those capabilities are not turned on by the car owner.
NOR flash is typically found in automotive systems that require fast bootup, including digital displays that running on Linux or Android operating systems, Kawaguchi said. There is a growing trend for higher code density. “NOR flash is going to be the ideal solution because of the cost and the performance balance.”
Despite industry discussions on the potential of emerging memories, such as embedded MRAM replacing NOR flash in some automotive applications, the NOR flash market is at a stable $3 billion, Kawaguchi noted, and the technology continues to be the best cost-per-bit NVM technology. The low density NOR flash memory market continues to be robust, he added. “There is going to be a constant continuous need for a lower density external or discrete flash product.”
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