Tag Archives: IAR

Atmel’s SAM4S clinches highest CoreMark/MHz scores

Atmel’s SAM4S MCU lineup – which clocks in at a top speed of 120MHz+ – is based on ARM’s Cortex-M4 core. The microcontroller series integrates a Flash read accelerator along with cache memory to increase system performance. Additional key specs include a multi-layer bus matrix, multi-channel direct memory access (DMA) and distributed memory to facilitate high data rate communication.

Recently, the EEMBC (Embedded Microprocessor Benchmark Consortium) certified five SAM4S MCU benchmark scores running a version of CoreMark compiled using the IAR Embedded Workbench for ARM version 6.50. As it turns out, Atmel’s SAM4S MCUs racked up the highest CoreMark/MHz for any Cortex-M microcontroller submitted to date.

“The CoreMark benchmark is designed to measure the performance of the processor core alone,” Atmel engineering rep Brian Hammill told Bits & Pieces.

“While the CoreMark may not always convey how well a particular part will perform in a specific application, it does offer an accurate test of core performance and efficiency. As such, CoreMark can be used to understand how the performance of a particular MCU and compiler combination compares to others.”

According to Hammill, the Atmel scores are particularly significant as they illustrate the overall efficiency of the Cortex-M4 cache implemented on the SAM4SA16 and SAM4SD32, as well as the optimized performance of the IAR Embedded Workbench version (6.50).

“Looking at the Atmel SAM4SD32CAU, we see the CoreMark for the IAR EWARM 6.50 was run at both 21 MHz and 123 MHz. If we run the EEMBC CoreMark report or export the data to Excel, here is what we see:


“As expected, the CoreMark scores are much higher at the faster clock speed. But what is most significant is the difference in the CoreMark/MHz scores. Notice that the 21 MHz CoreMark memory configuration is zero wait states. The memory configuration for the 123 MHz CoreMark is 5 wait states but with prefetch and cache enabled. You see a small difference in the CoreMark/MHz scores between the 21 and 123 MHz benchmarks.”

Why? Well, as Hammill, notes, if you had a perfect zero wait state memory or cache system, the exact same CoreMark/MHz would be returned regardless of the speed.

“Of course it is to be expected that the cache helps – but does not completely cover the wait states of Flash. However, the small difference between 3.32 CoreMark/Mhz at 123 MHz and 3.38 CoreMark/ MHz illustrates Atmel’s SAM4SD32CAU device has a very good implementation of cache and prefetch,” he explained.


“Indeed, if the Atmel cache and prefetch weren’t optimized, you would expect to see a much larger difference in the CoreMark/MHz scores. I would also like to note that the Atmel SAM4SD32CAU require 5 wait states in flash to run at 123 MHz – but with very slight performance penalty as indicated by the CoreMark/MHz scores.”


CoreMark – written in C – was developed in 2009 by Shay Gal-On at EEMBC and contains implementations of numerous algorithms. These include list processing (find and sort), Matrix (mathematics) manipulation (common matrix operations), state machine (determine if an input stream contains valid numbers) and CRC. Like any benchmark, the EEMBC CoreMark clearly isn’t perfect, although it is certainly a fair assessment of overall performance, as well as the core and memory efficiency of a specific processor.

Atmel expands ARM Cortex-M4 Flash lineup with SAM4N series

Atmel has expanded its ARM Cortex-M4 Flash lineup with the entry-point SAM4N series. The new microcontrollers – which feature a 100MHz operating frequency – boast up to 1MB of Flash memory, multiple serial communication peripherals and analog capability.

“This combination of features, coupled with low power consumption, makes the SAM4N series ideal for a wide range of applications, including the industrial automation, consumer appliance and energy metering markets,” an Atmel engineer told Bits and Pieces.

“In addition, the SAM4N series offers pin-to-pin compatibility with the Atmel SAM4S, SAM3S, SAM3N and SAM7S devices – facilitating easy migration within the SAM lineup.”

As noted above, the SAM4N is built around a low power sipping design, achieving real-world consumption levels down to 170µA/MHz in active mode; down to 20µA in sleep mode with full RAM retention & wake-up time down to 10µs; and down to 1µA in backup mode with the RTC running.

Key hardware specs include fast serial communication with 7 UARTs, four SPIs and three I2Cs; 12-bit ADC, 10-bit DAC, integrated voltage reference, multiple timers and PWM.

On the software side, there is full IDE support for Atmel Studio 6, IAR and Keil, while a Modbus Demo (RTOS + Modbus RTU) will go live later this month. In addition, Atmel’s SAM4N Xplained Pro is available as a starter or evaluation kit – and is probably the most ideal platform for evaluating and prototyping with the SAM4N. Of course, extension boards can also be purchased individually. Additional information about Atmel’s new SAM4N lineup can be found here.

What’s new in Atmel’s ARM MCU? picoPower!!

The SAM4L it is the first ARM device to feature Atmel’s picoPower technology, and takes low power to a new level.   There are many different characteristics that make a low power device; foremost it is the active power, the wake-up time and sleep mode power consumption. For the SAM4L, this can go down to 90 µA/MHz in active, down to 700 nA in sleep mode and down to 1.5 µs wake-up. Additionally the Cortex-M4 and Atmel’s fast flash technology allows your application to spend a shorter amount of time in active and spend more time in low power modes. All of this significantly reduces the total power consumption for your application.

picopower explained

Atmel SAM4L MCUs redefine the power benchmark, delivering the lowest power in both active (90uA/MHz) and sleep
modes (1.5uA with full random access memory (RAM) retention and 700nA in backup mode). They are the most efficient
MCUs available today, achieving up to 28 CoreMark™/mA using the IAR Embedded Workbench, version 6.40.

Check out this video for more information about picoPower in the SAM4L.  Also, please be sure to follow us on this blog to learn more on how these ARM devices become so power conscious and other neat application tutorials.  Or share, collaborate, and innovate with the other tens of thousands of engineers/builders in the vibrant AT91 community.