Tag Archives: AVR UC3C

32-bit AVR MCUs for automotive applications (Part 3)

In the first part of this series, we took a closer look at how Atmel’s AVR low-power 32-bit microcontrollers (MCUs) help enable the implementation of various product-differentiating features, including advanced control algorithms, voice control and capacitive touch sensing. In part two, we discussed powering Atmel’s AVR UC3C 32-bit automotive-grade microcontrollers with either a 3.3V or a 5V supply  (generally supporting 5V I/O) and focused on Atmel’s Peripheral Event System.


And today we will exploring how Atmel’s low-power 32-bit microcontrollers (MCUs) are used to help protect IP and bolster system safety. Firstly, it is important to note that code protection has become a critical design consideration, as software contains an increasing amount of intellectual property (IP). As such, internal Flash memory should be locked to protect code from being read or copied – with system development significantly accelerated by making application code available from third-party devs in a locked section of the Flash memory.

“Microcontrollers must either be programmed before they are assembled on boards or programmed in-device. Yet, preprogramming creates a challenge in logistics, as devices must be programmed in a trusted facility and transported to the manufacturing site,” an Atmel engineering rep told Bits & Pieces.

“In contrast, programming in-system allows the most recent code to be added during the manufacturing stage or in the field. The AVR UC3C arrives with USB drivers that support the Device Firmware Upgrade (DFU) class to allow devices to be programmed over the system’s USB port. As an alternative, a boot loader can be used to allow in-system programming using the CAN interface.”

And that is precisely why Atmel’s AVR UC3C 32-bit microcontroller architecture includes the Atmel FlashVault code protection technology, which allows the on-chip Flash to be partially programmed and locked, creating secure on-chip storage for software IP and boot loader operation.

On the system safety side, systems must be able to recover quickly from clock failure. Indeed, motor control systems must be able to shut systems down upon detection of clock failure to prevent severe damage to the motor or operator. To achieve this, the UC3C devices incorporate a main clock failure detection functionality that immediately switches over to the internal 115kHz RC oscillator in case of malfunction. The system may either continue operation using the backup clock (while triggering an alarm that the primary clock has failed) or perform any necessary shut-down operation to place the system in a fail-safe condition.

Interested in learning more about 32-bit AVR MCUs for automotive applications? Be sure to check out part four of this series which details how Atmel MCUs can be used to streamline automotive development. Part one can be read here and part two is available here.

Interested in learning more about 32-bit AVR MCUs for automotive applications? Be sure to check out part onetwothree and four of this series.

32-bit AVR MCUs for automotive applications (Part 1)

Atmel’s AVR low-power 32-bit microcontrollers (MCUs) provide higher processing performance, improved accuracy and optimized power efficiency for automotive applications. This facilitates implementation of new product-differentiating features such as advanced control algorithms, voice control and capacitive touch sensing.

More specifically, Atmel’s AVR UC3C 32-bit microcontroller (MCU) include a peripheral event system, precision clocking, and high-performance peripherals. Integrated features – such as secure Flash memory, hardware-based safety mechanisms, the ability to interface directly with analog sensors, and a configurable software framework. All of the above helps to significantly accelerate application development.

“Simply put, the difference in efficiency between 32- and 8-/16-bit systems is substantial: a generic 32-bit multiple/accumulate requires four multiplications and four additions on a 16-bit processor with additional overhead for data accessing,” an Atmel engineering rep told Bits & Pieces.

“Thus, a single 32-bit multiplication could require about 20-40 cycles on a 16-bit processor. On a 32-bit UC3C processor this operation requires only a single cycle supported with a 32-bit pipeline for rapid data access. The availability of an integrated FPU also simplifies application development. The implementation of complex algorithms in particular requires less effort and the wider dynamic range maintains the highest precision.”

According to the engineering rep, implementing complex algorithms using 32-bit floating-point instructions not only increases system accuracy and efficiency, but also helps accelerate the development cycle. Indeed, a wide variety of applications can benefit from the use of a floating-point unit, including motor control and audio applications.


“Atmel’s UC3C 32-bit microcontroller instruction set is an efficient mix of 16- and 32-bit instructions that allows C compilers to balance performance and code density. Its architecture has been optimized for managing real-time events common to embedded systems while minimizing processing latency,” the engineering rep continued. “The UC3C microcontroller also includes a wide variety of state-of-the-art peripherals and interfaces – such as CAN and LIN – required by automotive control modules (ECU), while also ensuring reliable operation across the entire automotive temperature range in compliance with the AECQ100 specification.”

Atmel AVR UC3C 32-bit automotive-grade microcontrollers can be powered either by a 3.3V or a 5V supply and generally support 5V I/O. This has been achieved by moving to a modified 0.18-micron process technology, which can support higher I/O voltage levels in a reliable and cost-effective manner without any complex and expensive voltage conversion.

In addition to supporting 5V I/O, the UC3C has been designed with a wide range of high-performance peripherals required by automotive applications, which will we discuss in-depth during part two of this series. Interested in learning more about 32-bit AVR MCUs for automotive applications? Be sure to check out part onetwothree and four of this series.