Atmel ARM-based processors

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Atmel ARM-based processors are microcontrollers and microprocessors integrated circuits, by Atmel, that are based on various 32-bit ARM processor cores, with Atmel-designed peripherals and tool support. Atmel's SMART-brand ARM families complements their AVR lines of 8- and 32-bit microcontrollers. The SMART brand includes application-specific ARM-based parts for Wi-Fi, such as the SmartConnect and Smart Direct lines, as well as ARM-based ICs meant for smart energy products such as gas and power meters.

The Atmel SMART brand of ARM-based MCUs are found in the Arduino family of single-board computers: Arduino Zero (SAM D21) and Arduino Due (SAM3). The “SAM” moniker in Atmel part numbers stands for “SMART Atmel microcontroller”.

The SMART line is a key component of Atmel’s Internet of Things (IoT) strategy. The 32-bit ARM cores are well-suited to host the TCP/IP software stack needed to communicate over the Internet. In addition to the microcontrollers needed for IoT, Atmel is using SMART ARM-based chips in several of its Wi-Fi modules and its line of Smart Energy integrated circuits.[1]

Traditionally there has been a tie-in between the Atmel part number and the ARM core that the part is based on. Going forward from 2014, Atmel is disjoining the ARM core labeling from the part number. Hence, the SAM D20 part number has no indication it is based on a ARM Cortex-M0+.


Main articles: ARM architecture and ARM Cortex-M

ARM licenses the core design for a series of 32-bit processors. ARM does not manufacture any complete silicon products, just intellectual property (IP). The ARM processors are RISC (reduced instruction set computers). This is similar to Atmel’s AVR 8-bit products, a later adoption of RISC architecture. Whereas the AVR architecture used Harvard architecture exclusively, the some ARM cores are Harvard (Cortex-M3) and others are Von Neumann (ARM7TDMI).

Semiconductor companies such as Atmel take the ARM cores, which use a consistent set of instructions and register naming, and add peripheral circuits such as ADC (analog to digital converters), clock management, and serial communications such as USART, SPI, CAN, LIN, and I2C. Atmel made efforts to adapt advanced peripherals and power management that used very little power and can operate independently without having the CPU core powered up (Sleepwalking). They also provided for DMA between external interfaces and memories increasing data throughput with minimal processor intervention.

Atmel sells both MCUs (microcontroller units) that have internal Flash memory, and MPUs (microprocessor units) that use external memory. In addition to the chips themselves, Atmel offers demo boards, both on its website, and through distribution channels such as Digi-key, Element14, Arrow, Avnet, Future Electronics, and Mouser.

Some of the Atmel | SMART line of ARM-based products are meant for specific applications, such as their SAM4CP that is used in smart-grid energy meters. There are also Atmel wireless products built on ARM cores, such as the SmartConnect and Smart Direct wireless chips and modules.


  • 1995 sign ARM ARM7TDMI “Thumb” core license agreement (ARMv4T Von Neumann architecture) (an MPU core Atmel made into MCU)
    • AT91M40800, (1998)
    • AT91M42800A,
    • AT91M55800A,
    • AT91R40008,
    • AT91FR40162 (2002)
    • SAM7S/SE,
    • SAM7X/XC,
    • SAM7L
  • 1995 sign ARM920T/ARM9TDMI (MPU) core license agreement (ARMv4T Von Neumann architecture)
    • AT91RM9200 (2003)
  • 2000 sign ARM926EJ/ARM9E (MPU) core license agreement (ARMv5 architecture)
    • AT91SAM9260, (2006)
    • AT91SAM9263, (2007)
    • SAM9XE, (2008)
    • SAM9N/CN,
    • SAM9R, (2009)
    • SAM9G, (2009)
    • SAM9X
    • SAM9M (2010)
  • 2004 sign ARM1176JZ-S core license agreement (not used in Atmel parts)
  • 2008 sign Cortex license agreement with ARM Holdings.[2]
    • Cortex-M3 (MCU) (ARMv7-M Harvard architecture)
      • SAM3U, (2009) [3]
      • SAM3S, (2009) [4]
      • SAM3N, (2010) [5]
      • SAM3A, (2012) [6]
      • SAM3X, (2012) [6]
    • Cortex-M4 (MCU) (ARMv7E-M Harvard architecture)
      • SAM4S, (2011) [7]
      • SAM4L, (2012) [8]
      • SAM4E, (2013) series based on the ARM Cortex-M4F, first Atmel MCU that has a FPU (Floating-Point Unit).[9]
      • SAM4N, (2013)
      • SAM4C, (2014) dual core [10]
      • SAM G51/53 (2014) based on the ARM Cortex-M4F.[11]
      • SAM G54/55 (2015) based on the ARM Cortex-M4F.[12]
    • Cortex-A5 (MPU) (ARMv7-A architecture)
      • SAMA5D3 series, (2013) Atmel announced the SAMA5D3 series based on the ARM Cortex-A5, which is the first Atmel chip with a Cortex-A5 core.[2]
      • SAMA5D4, (2014) [13]
    • Cortex-M0+ (MCU)in the SAM D20 (2013) (ARMv6-M architecture) In June 2013, Atmel announced the SAMD20 series based on the ARM Cortex-M0+.[14]


The Atmel | SMART branding is an umbrella for all AT91 ARM-based parts, even those without "SAM" in the name.


Microcontrollers have internal program memory as well as the conventional internal registers and RAM (random-access memory). Atmel ARM MCUs range from the SAM D10 series with as few as 14 pins, to the 144-pin SAM3 and SAM4 products.

The SAM4S, SAM4N, SAM3S, SAM3N, SAM7S (64-pin) families have pin-compatible IC footprints, except for USB device, though they are not voltage level compatible.[15]

SAM D[edit]

The SAM D[16] family from Atmel consists of 4 different sub series (SAM D10, SAM D11, SAM D20, SAM D21). The devices are all based on the ARM Cortex-M0+ processor and offer different pin, memory, and feature combinations. The devices are pin- and code-compatible and share peripherals like the Event System and the SERCOM module. The SAM D10 and D11 has been announced, but are not available yet.

SAM 4[edit]

The ATSAM4 is based on the ARM Cortex-M4 core. The SAM4E includes a FPU (Floating-Point Unit). The SAM4C includes a dual ARM Cortex-M4 core (one core with a FPU).

  • SAM4C - ARM Cortex-M4/M4F dual core, which includes FPU.
  • SAM4E - ARM Cortex-M4F core, which includes FPU.
  • SAM4L - ARM Cortex-M4 core.
  • SAM4N - ARM Cortex-M4 core. Pin-to-pin compatibility with SAM4S, SAM3S, SAM3N, SAM7S devices.
  • SAM4S - ARM Cortex-M4 core.
  • SAMG - ARM Cortex-M4F core, which includes FPU.

SAM 3[edit]

Arduino Due with Atmel SAM3X8E

In 2009 Atmel announced the ATSAM3U line of flash-based microcontrollers based on the ARM Cortex-M3 processor, as a higher end evolution of the SAM7 microcontroller products. They have a top clock speed in the range of 100 MHz, and come in a variety of flash sizes. In the summer 2009 these parts were still sampling, and a development board had recently been made available.

In December 2009, the ATSAM3S line was announced. This features several enhancements for lower power operation and bill of materials cost reduction.

Market watchers observe that these Cortex-M3 products are competition for Atmel's own AVR32 UC3A products. Both are microcontrollers with largely identical peripherals and other hardware technology, flash-based, similar clock speeds, and with dense 16/32 bit RISC instruction sets.

Legacy products[edit]

MYIR's MYD-SAM9X5-V2 board for Atmel AT91SAM9G and SAM9X processors

The AT91SAM9XE flash-based microcontrollers are based on the ARM926ej-s cores. They have a top clock speed in the range of 200 up to 400 MHz,[18] and come with a variety of flash sizes. They somewhat resemble flash-equipped AT91SAM9260 chips.

Atmel introduced the AT91SAM9 processors (using the ARM926ej-s core, with the ARMv5TEJ architecture) as its first broad market follow on to the highly successful AT91rm9200 processor. These processors improved on that predecessor by using less power, incorporating a newer and more powerful ARM core, and providing a variety of chips with different peripheral sets. While most are clocked at up to about 200 MHz, some can run at twice that speed. Processors include:


There are a wide variety of AT91 flash-based microcontrollers, based on ARM7TDMI cores. These chips have a top clock speed in the range of 60 MHz, and come with a variety of flash sizes and peripheral sets.

  • SAM7L - low power operation
  • SAM7S - USB and other peripherals. SAM7S 64-pin chips are compatible with SAM4S, SAM4N SAM3S, SAM3N families.
  • SAM7SE - USB, external memory support, and other peripherals
  • SAM7X - Ethernet, USB, CAN, and other peripherals
  • SAM7XC - cryptographic extensions (notably AES support) to AT91SAM7X chips


MYD-SAMA5D3X development board for Atmel SAMA5D3 ARM Cortex-A5 processors.

SAM A5D3[edit]

This series is based on the ARM Cortex-A5 core.[2][19]

  • SAMA5D31 - 10/100 Ethernet, LCD
  • SAMA5D33 - Gigabit Ethernet, LCD
  • SAMA5D34 - Gigabit Ethernet, LCD, dual CAN
  • SAMA5D35 - no LCD, dual CAN, one Gigabit Ethernet + one 10/100 Ethernet
  • SAMA5D36 - LCD, dual CAN, one Gigabit Ethernet + one 10/100 Ethernet

SAM A5D4[edit]

  • SAMA5D4 - 528Mhz(840DMIPS), Neon, 128K L2 Cache, Video Decoder, LCD, Ethernet


  • SmartConnect
  • Smart Direct

Smart Energy[edit]

  • SAM 4C/CM

Development boards[edit]

MYD-SAMA5D3X-C development board for Atmel SAMA5D3 ARM Cortex-A5 processor designed by MYIR.
MCC-SAMA5D3X-C CPU Module for Atmel SAMA5D3 ARM Cortex-A5 processor designed by MYIR.

Atmel boards[edit]

  • Xplained Pro
  • Xplained
  • SAM W21
  • SAMA5

Arduino boards and compatibles[edit]

See also: Arduino
  • Arduino Zero with Atmel SAM D21 ARM Cortex M0+ core.
  • Arduino Due with Atmel ATSAM3X8E (84 MHz Cortex-M3) microcontroller.
  • Shield-compatible Rascal with Atmel AT91SAM9G20 (400 MHz ARM926EJ-S) microcontroller.

MYIR boards[edit]

Development tools[edit]

Segger J-Link EDU. JTAG / SWD debug probe for ARM microcontrollers with USB interface to host. Low price model for home users and educational use.



Integrated development environments:

  • Atmel - Studio 6
  • IAR - Embedded Workbench for ARM
  • Buildroot [28]
  • Openembedded [29]
  • meta-atmel Yocto compliant layer[30]


  • Atmel-ICE
  • Segger J-Link


The amount of documentation for all ARM chips is daunting, especially for newcomers. The documentation for microcontrollers from past decades would easily be inclusive in a single document, but as chips have evolved so has the documentation grown. The total documentation is especially hard to grasp for all ARM chips since it consists of documents from the IC manufacturer (Atmel) and documents from CPU core vendor (ARM Holdings).

A typical top-down documentation tree is: manufacturer website, manufacturer marketing slides, manufacturer datasheet for the exact physical chip, manufacturer detailed reference manual that describes common peripherals and aspects of a physical chip family, ARM core generic user guide, ARM core technical reference manual, ARM architecture reference manual that describes the instruction set(s).

Atmel ARM documentation tree (top to bottom)
  1. Atmel ARM-series website.
  2. Atmel ARM-series marketing slides.
  3. Atmel ARM-chip datasheet.
  4. Atmel ARM-chip reference manual.
  5. ARM core website.
  6. ARM core generic user guide.
  7. ARM core technical reference manual.
  8. ARM architecture reference manual.

Atmel has additional documents, such as: evaluation board user manuals, application notes, getting started guides, software library documents, errata, and more. See External Links section for links to official Atmel and ARM documents.

See also[edit]


  1. ^ Atmel product website
  2. ^ a b c Press Release; Atmel; February 4, 2013.
  3. ^ Press Release; Atmel; June 1, 2009.
  4. ^ Press Release; Atmel; December 15, 2009.
  5. ^ Press Release; Atmel; November 9, 2010.
  6. ^ a b Press Release; Atmel; February 28, 2012.
  7. ^ Press Release; Atmel; October 26, 2011.
  8. ^ Press Release; Atmel; September 24, 2012.
  9. ^ Press Release; Atmel; January 14, 2013.
  10. ^ Press Release; Atmel; August 12, 2014.
  11. ^ Press Release; Atmel; January 7, 2014.
  12. ^ Press Release; Atmel; January 5, 2015.
  13. ^ Press Release; Atmel; October 1, 2014.
  14. ^ Press Release; Atmel; June 17, 2013.
  15. ^ Pin-compatible Cortex replacement for Atmel ARM7 SAM7S derivatives; ECE; May 2011.
  16. ^ Microsite; Atmel; July 11, 2014.
  17. ^ Arduino Due;
  18. ^
  19. ^ SAM5A webpage;
  20. ^ MYIR; Development Board for Atmel AT91SAM9G15, SAM9G25, SAM9G35, SAM9X25 and SAM9X35 ARM9 processors.
  21. ^ MYIR; Controller Board for Atmel AT91SAM9G15, SAM9G25, SAM9G35, SAM9X25 and SAM9X35 ARM9 processors.
  22. ^ MYIR; Development Board for Atmel AT91SAM9G15, SAM9G25, SAM9G35, SAM9X25 and SAM9X35 ARM9 processors.
  23. ^ MYIR; Controller Board for Atmel AT91SAM9G15, SAM9G25, SAM9G35, SAM9X25 and SAM9X35 ARM9 processors.
  24. ^ MYIR; Development Board for Atmel ATSAMA5D31, SAMA5D33, SAMA5D34, SAMA5D35 and SAMA5D36 ARM Cortex-A5 processors.
  25. ^ MYIR; Controller Board for Atmel ATSAMA5D31, SAMA5D33, SAMA5D34, SAMA5D35 and SAMA5D36 ARM Cortex-A5 processors.
  26. ^ MYIR; Development Board for Atmel ATSAMA5D31, SAMA5D33, SAMA5D34, SAMA5D35 and SAMA5D36 ARM Cortex-A5 processors.
  27. ^ MYIR; Controller Board for Atmel ATSAMA5D31, SAMA5D33, SAMA5D34, SAMA5D35 and SAMA5D36 ARM Cortex-A5 processors.
  28. ^ Buildroot
  29. ^ Openembedded
  30. ^ meta-atmel Yocto Compliant layer

Further reading[edit]

ARM Cortex-M
  • Digital Signal Processing and Applications Using the ARM Cortex M4; 1st Edition; Donald Reay; Wiley; 250 pages; 2014; ISBN 978-1118859049.
  • Assembly Language Programming : ARM Cortex-M3; 1st Edition; Vincent Mahout; Wiley-ISTE; 256 pages; 2012; ISBN 978-1848213296.
  • The Definitive Guide to the ARM Cortex-M3 and Cortex-M4 Processors; 3rd Edition; Joseph Yiu; Newnes; 600 pages; 2013; ISBN 978-0124080829.
  • The Definitive Guide to the ARM Cortex-M0; 1st Edition; Joseph Yiu; Newnes; 552 pages; 2011; ISBN 978-0-12-385477-3.

External links[edit]

AT91SAM Official Documents
ARM Official Documents