AT91SAM (AT91SAM Smart ARM-based Microcontrollers) are a family of Atmel chips based on the 32-bit RISC microprocessors from ARM[1]. 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 microcontrollers they include embedded Flash and SRAM memories together with a number of peripherals 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 regulators 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.
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-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. 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.
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
References
External links
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