Tag Archives: industrial communications

Simply the highest performing Cortex-M MCU

Why develop a new MCU instead of using a high-performance MPU? Eric Esteve says “simplicity.”

By Eric Esteve

If you target high growth markets like wearable (sport watches, fitness bands, medical), industrial (mPOS, telematics, etc.) or smart appliances, you expect using a power efficient MCU delivering high DMIPs count. We are talking about systems requiring a low bill of material (BoM) both in terms of cost and devices count. Using a MCU (microController) and not a MPU (microProcessor) allows for the minimizing of power consumption as such device like the SAM S70 runs at the 300 MHz range, not the GigaHertz, while delivering 1500 CoreMark. In fact, it’s the industry’s highest performing Cortex-M MCUs, but the device is still a microcontroller, offering multiple interface peripherals and the related control capabilities, like 10/100 Ethernet MAC, HS USB port (including PHY), up to 8 UARTs, two SPI, three I2C, SDIOs and even interfaces with Atmel Wi-Fi and ZigBee companion IC.

Atmel has a wide MCU offering from the lower end 8-bit MCU to the higher end Cortex-A5 MPU.

The Cortex-M7 family fits within the SAM4 Cortex-M4 and the SAM9 ARM9 products.
The Cortex-M7 family offers high performance up to 645 Dhrystone MIPS but as there is no Memory Management Unit, we can not run Operating System such as Linux. This family targets applications with high performance requirements and running RTOS or bare metal solution.

This brand new SAM S/E/V 70 32-bit MCU is just filling the gap between the 32-bit MPU families based on Cortex-A5 ARM processor core delivering up to 850 DMIPS and the other 32-bit MCU based on ARM Cortex-M. Why develop a new MCU instead of using one of this high performance MPU? Simplicity is the first reason, as the MCU does not require using an operating system (OS) like Linux or else. Using a simple RTOS or even a scheduler will be enough. A powerful MCU will help to match increasing application requirements, like:

  • Network Layers processing (gateway IoT)
  • Higher Data Transfer Rates
  • Better Audio and Image Processing to support standard evolution
  • Graphical User Interface
  • Last but not least: Security with AES-256, Integrity Check Monitor (SHA), TRNG and Memory Scrambling

Building MCU architecture probably requires more human intelligence to fulfill all these needs in a smaller and cheaper piece of silicon than for a MPU! Just look at the SAM S70 block diagram below, for instance.

SAM S70 Block diagram

SAM S70 Block diagram

The memory configuration is a good example. Close to the CPU, implementing 16k Bytes Instruction and 16k Bytes Data caches is a well-known practice. On top of the cache, the MCU can access Tightly Coupled Memories (TCM) through a controller running at MPU speed, or 300 MHz. These TCM are part of (up to) 384 Kbytes of SRAM, implemented by 16 Kbytes blocks and this SRAM can also be accessed through a 150 MHz bus matrix by most of the peripheral functions, either directly through a DMA (HS USB or Camera interface), either through a peripheral bridge. The best MCU architecture should provide the maximum flexibility: a MCU is not an ASSP but a general purpose device, targeting a wide range of applications. The customer benefits from flexibility when partitioning the SRAM into System RAM, Instruction TCM and Data TCM.

SRAM Partition Atmel Cortex M7
As you can see, the raw CPU performance efficiency can be increased by smart memory architecture. However, in terms of embedded Flash memory, we come back to a basic rule: the most eFlash is available on-chip, the easier and the safer will be the programming. The SAM S70 (or E70) family offers 512 Kbytes, 1 MB or 2 MB of eFlash… and this is a strong differentiator with the direct competitor offering only up to 1 MB of eFlash. Nothing magical here as the SAM S70 is processed on 65nm when the competition is lagging on 90nm. Targeting a most advanced node is not only good for embedding more Flash, it’s also good for CPU performance (300 MHz delivering 1500 DMIPS, obviously better than 200 MHz) — and it’s finally very positive in power consumption.

Indeed, Atmel has built a four mode strategy to minimize overall power consumption:

  • Backup mode (VDDIO only) with low power regulators for SRAM retention
  • Wait mode: all clocks and functions are stopped except some peripherals can be configured to wake up the system and Flash can be put in deep power down mode
  • Sleep mode: the processor is stopped while all other functions can be kept running
  • Active mode
Atmel's SMART | ARM Cortex M7 SAM S Series Target Applications

Target Applications depicted above for Atmel’s SMART | ARM based Cortex M7 SAM S Series. The SAM S series are general-purpose Flash MCUs based on the high-performance 32-bit ARM based Cortex-M7 RISC processors with floating point unit (FPU).

If you think about IoT, the SAM S70 is suited to support gateway applications, among many other potential uses, ranging from wearable (medical or sport), industrial or automotive (in this case it will be the SAM V70 MCU, offering EMAC and dual CAN capability on top of S70).

This post has been republished with permission from SemiWiki.com, where Eric Esteve is a principle blogger as well as one of the four founding members of SemiWiki.com. This blog first appeared on SemiWiki on February 22, 2015.

Front and center with Atmel’s ARM-powered SAM9

Atmel’s versatile ARM-powered SAM9 has popped up in a number of recent Bits & Pieces articles lately. So today we will be taking a closer look at the most current SAM9 MCU lineup (SAM9G15, SAM9G25, SAM9G35, SAM9X25, SAM9X35) which is capable of driving a wide range of hardware-based applications, including industrial communicationsPLC systems & I/O modules, human machine interfaces and the industrial Matrix-505 by Artila Electronics.

“Essentially, Atmel’s ARM926-based Atmel SAM9 microcontrollers deliver expanded feature sets – including enhanced display and connectivity peripherals – offering engineers the flexibility to design industrial and commercial applications that make a difference,” an Atmel engineering rep told Bits & Pieces.

“High levels of performance and integration coupled with reduced system cost make Atmel SAM9 processors ideal for main-powered, cost-sensitive applications such as industrial and building control, HVAC, POS terminals, smart grid, printers and medical.”

In terms of integration, connectivity peripherals include up to three USB ports, CAN, Ethernet, SDIO/SDCard/MMC and a unique integrated soft modem. Meanwhile, display peripherals boast a graphics LCD controller with 4-layer overlay and 2D acceleration (picture-in-picture, alpha-blending, scaling, rotation, color conversion), camera and touch-screen interfaces.

“For high-performance architecture, Atmel’s SAM9 series features a processor clock running at 400 MHz, along with a high data-bandwidth architecture based on a multi-layer bus matrix with dual 8-channel central Direct Memory Access (DMA) controllers,” the engineering rep continued. “Plus, the lineup offers dedicated DMAs to support the high-speed connectivity peripherals.”


As expected, the above-mentioned devices offer LPDDR, DDR2 and MLC NAND Flash support, in addition to SDRAM and NOR Flash, with boot from NAND Flash, SDCard, DataFlash or serial DataFlash. They also support up to 24-bit error code correction on MLC NAND Flash. As with other Atmel MCUs, full-featured evaluation kits are available with free board support packages (BSP) for Linux, with development tools, OS, middleware products and support from industry-leading partners.

Last, but certainly not least, power consumption is only 300µW/MHz at 400MHz operation and 8µA in backup mode, with 3.3V IOs eliminating the need for external level shifters while 0.8mm ball pitch packages simplify PCB design.

Interested in learning more? Be sure to check out our breakdown of SAM9-based devices below for specific key specs:

Powering industrial communications with Atmel

Industrial communications are a critical aspect of current-gen automated systems – with defined standards that continue to evolve as new industrial Ethernet protocols emerge. Atmel’s versatile portfolio of microcontrollers (MCUs) provides engineers with the peripherals and internal system architecture required to efficiently interface new products with leading field busses, industrial Ethernet standards and wireless communications.

Field Bus

Atmel offers a dedicated RS485 mode for USART peripherals which is available on most ARM processor-based AT91SAM and AVR 32-bit microcontrollers. Meanwhile, a rich number of DMA channels on Atmel megaAVR, AVR XMEGA, AVR 32-bit and AT91SAM MCUs unload the CPU during industrial communication transfers, with multi-layer bus implementation on Atmel 32-bit microcontrollers enabling true parallel data transfers and effectively minimizing bus load limitation.

In addition, there is an (optional) external bus interface on several Atmel microcontrollers, with up to 32-bit data supports dedicated ASSP for protocols such as Profibus. Plus, up to 12Mbps USART on the SAM3U and SAM9 microcontrollers provides support for external transceivers. In terms of single or dual CAN controllers, select Atmel MCUs are V2.0A and V2.0B standard compliant, supporting independent message objects that are programmable on the fly and ideal for field bus such as CANopen and DeviceNet.

Industrial Ethernet

The vertical integration of management execution systems with factory floor equipment has resulted in the continued convergence of the Ethernet TCP/IP protocol with industrial field busses. As noted above, several industrial Ethernet protocols have emerged, including Profinet, Ethernet/IP, ModbusTCP/IP, EtherCat and Ethernet Powerlink.

“Most industrial Ethernet automated systems do not require compliance with a PLC cycle times lower than a few milliseconds. For these applications, the industrial Ethernet protocol can be cost-effectively implemented in software on a microcontroller with an integrated standard Ethernet MAC peripheral,” an Atmel engineering rep told Bits & Pieces.

“Due to their moderate flash size requirement, protocols like Modbus TCP can be implemented in a microcontroller. Atmel offers ARM-based and 32-bit AVR microcontrollers with up to 512KB of flash and an integrated Ethernet MAC unit.”

According to the rep, one of the most noteworthy features includes a 10/100 Ethernet Media Access Controller (EMAC) peripheral with chained buffer Direct Memory Access (DMA). This acts as a master on the internal multi layer bus with multiple internal SRAM blocks – enabling a true parallel data transfer between the Ethernet frames and the application data.

“Atmel’s  SAM9  MPUs are also price-competitive solutions for implementing industrial Ethernet protocols, such as the Ethernet/IP standard, which requires a higher flash size and faster execution time,” the engineering rep continued.

“Atmel’s  SAM9 MPU, like the SAM9G45, offers a variety of benefits, including a 400Mhz clocked ARM926EJ core with 32KB instruction and data caches speed execution time. There is also deterministic execution time with the use of the TCM (Tightly Coupled Memory) interface, enabling access to the internal SRAM with zero wait state at 400MHz. Indeed, by dynamically configuring the SRAM as TCM, Ethernet frames can be analyzed at full speed without any copy to the cache.”

For motion control applications, synchronism and short latency aspects are crucial. Protocols such as Profinet IRT or Ethercat address these requirements and are suited for systems with a sub-millisecond PLC times. In this case, specific ASSP or FPGA solutions must be used. The Atmel SAM9G45, with its dual EBI feature, lets designers integrate the industrial Ethernet communication module with minimal performance impact. Data transfers between the ASIC or FPGA can be handled by the DMA unit, in parallel with external RAM access.

Wireless Communication

Wireless communication in the industrial automation sector is increasingly popular, as it provides an easier way to install and connect mobile or inaccessible equipment. To be sure, industrial control equipment such as PLC and DCS IO modules primarily utilize IEEE802.11 WLAN and Bluetooth standards. And that is one of the reasons Atmel’s 32-bit microcontrollers and microprocessors feature an embedded multimedia card interface which supports connection to an SDIO WLAN or Bluetooth module. In fact, a full reference design based on the Atmel AVR 32-bit microcontroller and the industrial Wifi Module from H&D is available for evaluation and development here, while a Linux-based solution for Atmel SAM9 microcontrollers can be found here.

And last, but certainly not least, industrial sensors and actuators have demanding requirements for power consumption, board space and implementation cost. For these products, IEEE802.15.4 technology, such as Zigbee or Wireless-HART is most appropriate, with Atmel offering complete wireless solutions based on our low-power microcontrollers and RF transceivers. Benefits include excellent RF performance, which enables longer range and more robust RF link, optimized power consumption and lowest system cost.

Additional information about Atmel MCUs that can be used to power a wide range of industrial communication devices is available here.