New 600MHz Test Chip Combines Enhanced Built-In Self-Test
Functionality and Gigabit Ethernet Interface
TOKYO–(BUSINESS WIRE)–lt;a href=”https://twitter.com/hashtag/ISSCC?src=hash” target=”_blank”gt;#ISSCClt;/agt;–Renesas Electronics Corporation (TSE: 6723), a premier supplier of
advanced semiconductor solutions, today announced the development and
successful operation verification of an automotive test chip as a
technological stepping stone toward the realization of next-generation
automotive-control flash Microcontrollers (MCUs) employing a 28
nanometer (nm) low-power process.
The MCU features four 600 megahertz (MHz) CPUs with a lock-step
mechanism and a large 16 MB flash memory capacity, as well as:
Virtualization-assisted functions enabling MCU virtualization: This
technology allows multiple software components to run on a single MCU
without interfering with each other, thereby satisfying the
requirements of ASIL D, the highest automotive safety integrity level
specified under the ISO 26262 functional safety standard for road
Enhanced built-in self-test (BIST) functionality for MCU
self-diagnostic fault-detection necessary to implement ASIL D, thanks
to a newly developed standby-resume BIST (SR-BIST) function that is
executed during the standby-resume period.
Enhanced networking functionality, including Gigabit Ethernet
interface for high-speed transfer of sensor information.
Renesas presented the test results in the session, “A 28nm 600MHz
Automotive Flash Microcontroller with Virtualization-Assisted Processor
for Next-Generation Automotive Architecture Complying with ISO 26262
ASIL D,” on February 18 at International Solid-State Circuits Conference
(ISSCC) 2019, February 17-21, 2019, in San Francisco.
New electrical/electronic (E/E) architectures are driving demand for the
integration of multiple electronic control units (ECUs) into single ECUs
that support multiple functions. Achieving this level of integration
requires higher performance, reduced power consumption, and large
capacity flash memory. Automotive MCUs are also challenged with the
requirements of running software components with varying safety
integrity levels simultaneously and without mutual interference. In
addition to requiring software independence, automotive control demands
real-time responsiveness. To meet these next-generation requirements,
Renesas has developed new technologies led by virtualization-assisted
functions for automotive-control MCUs, as demonstrated in the new test
Key features of the newly-developed test chip
Hardware-based virtualization-assisted functions
Typically, software-based (hypervisor) virtualization requires greater
processing time due to the need to emulate hardware virtually. The
increased processing time required by the hypervisor to change between
CPU states (context switching), deliver interrupts, etc., poses problems
for automotive-control MCUs that must maintain real-time responsiveness.
To address this issue, Renesas developed a hardware-based
virtualization-assisted functions that dramatically reduces (Note 1) the
virtualization overhead, thereby boosting responsiveness. It allows
software components with varying safety integrity levels to operate
independently, making it possible for the MCU to deliver both
virtualization and real-time performance as required by ASIL D.
Standby-resume built-in self-test (BIST) function
BIST functions are a requirement in achieving ASIL D safety integrity
levels, to enable the MCU to perform self-diagnostics on the MCU while
it is running. One way to avoid disturbing a CPU processing period would
be to perform self-diagnostics in the period between when the MCU enters
the standby state and when resume occurs. However, there is limitation
regarding current fluctuations, so the increase in the current
fluctuation rate caused by resume due to self-diagnostics is a concern.
Renesas has developed standby-resume BIST (SR-BIST) to minimize the
current fluctuation rate. SR-BIST runs before the CPU begins operating
each time there is a transition from standby to resume. To ensure rapid
startup, the on-chip oscillator supplies a clock for the fault
diagnostics. An N/M divider is used to gradually increase the frequency
of the clock, reducing the current fluctuation rate (Note 2) when
SR-BIST is executing. As a result, it allows functional safety that
meets the requirements of ASIL D.
SGMII-compliant Gigabit Ethernet interface with 5V support
The next-generation of autonomous driving cars and connected cars will
employ large numbers of sensors and cameras, which will require Ethernet
as a high-speed communication interface to handle the enormous amount of
data generated by these devices. Nevertheless, automotive MCU interface
circuits continue to rely on 5V transistors for reliability reasons tied
to voltage surges. Therefore, Renesas has developed a Gigabit Ethernet
interface using 5V transistors that supports the Serial Gigabit Media
Independent Interface (SGMII) standard and provides excellent electrical
noise tolerance. To deal with deterioration of the signal bandwidth due
to the use of 5V transistors, dedicated circuits were added for receiver
and driver. This results in signal quality that complies with the SGMII
standard (Note 3).
Based on the technologies verified in the test chip, Renesas plans to
aggressively develop new 28nm flash MCUs and continue its commitment to
enabling a new generation of eco-friendly and autonomous driving cars
and helping to realize a safer and more secure driving experience.
(Note 1) Interrupt to a currently active virtual machine (VM) is
activated directly without having to go through the hypervisor.
Low-priority interrupt to a background VM is suspended until the VM is
activated. This reduces the interrupt overhead to zero, a 100-percent
reduction from the previous level.
(Note 2) In experimental results using the test chip, the current
fluctuation rate is reduced to one-sixth the previous level by SR-BIST.
(Note 3) Decreasing the source impedance of the receiver circuit and
compensating for attenuation of output from the driver circuit reduced
by 50 percent the rise/fall time of waveforms in simulations and boosted
reception waveform amplitude by 22 percent. The measured test results
also confirmed that transmission eye pattern meets the SGMII standard.
About Renesas Electronics Corporation
Renesas Electronics Corporation (TSE:
6723) delivers trusted embedded design innovation with complete
semiconductor solutions that enable billions of connected, intelligent
devices to enhance the way people work and live. A global
leader in microcontrollers, analog, power, and SoC products, Renesas
provides comprehensive solutions for a broad range of automotive,
industrial, home electronics, office automation, and information
communication technology applications that help shape a limitless
future. Learn more at renesas.com.
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Renesas Electronics Corporation