AT91SAM
Encyclopedia
AT91SAM are a family of Atmel
chips based on the 32-bit
RISC
microprocessors from ARM
. Some are targeted as applications processors, with external memory busses used to access RAM (SDRAM or DDR2) and flash, and large sets of integrated peripherals. When targeted as microcontroller
s they include embedded Flash
and SRAM
memories together with a number of peripheral
s and standard communications and networking interfaces. This qualifies them as system-on-a-chip
devices.
The AT91SAM comes in ARM7, ARM9 and Cortex M3 versions.
External interfaces include USB
, CAN, Ethernet
, SPI
, USART and ADC
. A DMA
controller provides direct communication channels between external interfaces and memories, increasing data
throughput with minimal processor
intervention.
Peripherals include counter/timers, power-on reset
generators, voltage regulator
s and advanced interrupt controller. This enhances the real-time
performance of the processor. A power management
controller keeps power consumption to a minimum by powering down unused peripherals and interfaces, and enabling the processor to be put in standby mode.
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. At this writing (Summer 2009) these parts are still sampling, and a development board has recently been made available.
In December 2009, the AT91sam3s line was announced. This features several enhancements for lower power operation and bill of materials
cost reduction. Also, the 64-pin parts are pin-compatible with AT91sam7 chips, facilitating upgrades of existing product designs.
Market watchers observe that these CM3 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.
Atmel
Atmel Corporation is a manufacturer of semiconductors, founded in 1984. Its focus is on system-level solutions built around flash microcontrollers...
chips based on the 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
RISC
Reduced instruction set computer
Reduced instruction set computing, or RISC , is a CPU design strategy based on the insight that simplified instructions can provide higher performance if this simplicity enables much faster execution of each instruction. A computer based on this strategy is a reduced instruction set computer...
microprocessors from ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
. Some are targeted as applications processors, with external memory busses used to access RAM (SDRAM or DDR2) and flash, and large sets of integrated peripherals. When targeted as microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
s they include embedded Flash
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...
and SRAM
Static random access memory
Static random-access memory is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM , it does not need to be periodically refreshed, as SRAM uses bistable latching circuitry to store each bit...
memories together with a number of peripheral
Peripheral
A peripheral is a device attached to a host computer, but not part of it, and is more or less dependent on the host. It expands the host's capabilities, but does not form part of the core computer architecture....
s and standard communications and networking interfaces. This qualifies them as system-on-a-chip
System-on-a-chip
A system on a chip or system on chip is an integrated circuit that integrates all components of a computer or other electronic system into a single chip. It may contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single chip substrate...
devices.
The AT91SAM comes in ARM7, ARM9 and Cortex M3 versions.
External interfaces include USB
Universal Serial Bus
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
, CAN, Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
, SPI
Serial Peripheral Interface Bus
The Serial Peripheral Interface Bus or SPI bus is a synchronous serial data link standard named by Motorola that operates in full duplex mode. Devices communicate in master/slave mode where the master device initiates the data frame. Multiple slave devices are allowed with individual slave select ...
, USART and ADC
Analog-to-digital converter
An analog-to-digital converter is a device that converts a continuous quantity to a discrete time digital representation. An ADC may also provide an isolated measurement...
. A DMA
Direct memory access
Direct memory access is a feature of modern computers that allows certain hardware subsystems within the computer to access system memory independently of the central processing unit ....
controller provides direct communication channels between external interfaces and memories, increasing data
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
throughput with minimal processor
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
intervention.
Peripherals include counter/timers, power-on reset
Power-on reset
A power-on reset generator is a microcontroller or microprocessor peripheral that generates a reset signal when power is applied to the device...
generators, voltage regulator
Voltage regulator
A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components...
s and advanced interrupt controller. This enhances the real-time
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
performance of the processor. A power management
Power management
Power management is a feature of some electrical appliances, especially copiers, computers and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power state when inactive. In computing this is known as PC power management and is built...
controller keeps power consumption to a minimum by powering down unused peripherals and interfaces, and enabling the processor to be put in standby mode.
Hardware Versions
Note that the AT91SAM branding is now an umbrella for all AT91 parts, even those without AT91SAM name prefixes.ARM7TDMI Based Microcontrollers
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.- AT91x40 series
- AT91sam7l series ... low power operation
- AT91sam7s series ... with USB and other peripherals
- AT91sam7se series ... with USB, external memory support, and other peripherals
- AT91sam7x series ... with Ethernet, USB, CAN, and other peripherals
- AT91sam7xc series ... cryptographic extensions (notably AES support) to AT91sam7x chips
- ... more
ARM926 Based Microcontrollers
The AT91sam9xe flash-based microcontrollers are based on the ARM926ej-s cores. They have a top clock speed in the range of 200 MHz, and come with a variety of flash sizes. They somewhat resemble flash-equipped AT91sam9260 chips.Cortex-M3 Based Microcontrollers
In 2009 Atmel announced the AT91sam3u line of flash-based microcontrollers based on the Cortex-M3ARM Cortex-M3
The ARM Cortex-M3 is an ARM processor core licensed by ARM Holdings. The core is intended for microcontroller applications.-Features:Key features of the Cortex-M3 core are:* ARMv7-M architecture* Support for Thumb and Thumb-2 instruction encodings...
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. At this writing (Summer 2009) these parts are still sampling, and a development board has recently been made available.
In December 2009, the AT91sam3s line was announced. This features several enhancements for lower power operation and bill of materials
Bill of materials
A bill of materials is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, components, parts and the quantities of each needed to manufacture an end product...
cost reduction. Also, the 64-pin parts are pin-compatible with AT91sam7 chips, facilitating upgrades of existing product designs.
Market watchers observe that these CM3 products are competition for Atmel's own AVR32
AVR32
The AVR32 is a 32-bit RISC microprocessor architecture designed by Atmel. The microprocessor architecture was designed by a handful of people educated at the Norwegian University of Science and Technology, including lead designer Øyvind Strøm, PhD and CPU architect Erik Renno, M.Sc in Atmel's...
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.
ARM9 Based Application Processors
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:- AT91rm9200 ... using the older ARM920t core, with the ARMv4T architecture
- AT91sam9260
- AT91sam9261, AT91sam9261S
- AT91sam9263
- AT91sam9g10
- AT91sam9g20
- AT91sam9g45
- AT91sam9r64
- AT91sam9rl64
External links
- Apexar Technologies S.A. AT91SAM9G45/M10 SOM's
- Atmel AT91 ARM Microcontroller Forum
- Atmel AT91 Embedded Linux support
- OpenEmbedded supports cross-compilation for thousands of packages for the AT91
- KaeilOS open source build-system supporting the cross compilation for the AT91 family of Microcontrollers
- Embest provides standard single board computers and custom modules based on Atmel SAM9260/SAM9261/SAM9263/SAM9G45 processors.