Atmel ARM-based processors

Atmel ARM-based processors are microcontrollers and microprocessors integrated circuits, by Microchip Technology (previously Atmel), that are based on various 32-bit ARM processor cores, with in-house designed peripherals and tool support.
Overview.
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 computing). This is similar to Microchip’s AVR 8-bit products, a later adoption of RISC architecture. Whereas the AVR architecture used Harvard architecture exclusively, some ARM cores are Harvard (Cortex-M3) and others are Von Neumann architecture (ARM7TDMI).
Semiconductor companies such as Microchip take the ARM cores, which use a consistent set of instructions and register naming, and add peripheral circuits such as ADCs (analog to digital converters), clock management, and serial communications such as USART, SPI, I2C, CAN, LIN, USB, Ethernet, and LCD, Camera or Touch controllers. Microchip 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.
Microchip sells both MCUs (microcontroller units) that have internal Flash memory, and MPUs (microprocessor units) that use external memory. In addition to the chips themselves, Microchip offers demo boards, both on its website, and through distribution channels such as Digi-key, Farnell, Ineltek, Arrow, Avnet, Future Electronics, and Mouser.
Some of the Microchip ARM-based products are meant for specific applications, such as their SAM4CP that is used in smart-grid energy meters. 
Products.
Microcontrollers.
Microcontrollers have internal program memory as well as the conventional internal registers and RAM. Microchip ARM MCUs range from the SAM D10 series with as few as 14 pins, to the 144-pin SAM S70 and SAM E70 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.
SAM C.
The Atmel C family was launched in May 2015. Based on Cortex-M0+, pin and code compatible with the SAM D and SAM L series, with wide operating voltage ranges (2.7–5.5 V), CAN bus, and up to 12 DMA controller channels. 
SAM D.
The SAM D family from Microchip consists of four 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 [[Arduino]] Zero board uses an ATSAMD21G18 chip.
The SAM D5X/E5X features the 32-bit Cortex-M4F.
SAM 3.
[[File:ArduinoDue Front.jpg|thumb|300px|right|[[Arduino]] Due board with Atmel ATSAM3X8E ([[ARM Cortex-M3]] core) microcontroller]]
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.
SAM 4.
The ATSAM4 is based on the [[ARM Cortex-M4]] core. The SAM4E includes a FPU ([[floating-point unit|Floating-Point Unit]]). The SAM4C includes a dual-core [[ARM Cortex-M4]] (one core with a FPU).
1st of August 2017, the ATSAMD5x and ATSAME5x family was announced. This features several enhancements for lower power operation and more peripherals, Ethernet and CANBUS-FD in SAME5x series. 
SAM x70.
These are based on the [[ARM Cortex-M7]] core.
Legacy.
AT91SAM7.
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.
Microprocessors.
AT91SAM9.
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, and come with a variety of flash sizes. They somewhat resemble flash-equipped AT91SAM9260 chips.
Microchip 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:
SAMA5.
This series is based on the [[ARM Cortex-A5]] core.
Development tools.
IDE.
Integrated development environments:
Documentation.
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 (for example, [[Microchip]]) 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).
Microchip has additional documents, such as: evaluation board user manuals, application notes, getting started guides, software library documents, errata, and more. See [[#External links|External Links]] section for links to official Microchip and ARM documents.
External links.
[[Category:Microcontrollers]]
[[Category:ARM architecture]]