Somehow I’ve been sticked to NXP LPC2xxx series microcontrollers and left other brands behind. There are many major manufacturers of ARM microcontrollers. One of them that is worth to pay attention is Atmel with its AT91SAM7 (Smart ARM7) series. SAM7 series of microcontrollers have built in Flash memory and data memory as well. Core is powered with 1.8V while peripherals need 3.3V. Core voltage is converted inside the chip so you don’t have to bother about this and only apply stabile 3.3V voltage. SAM7 microcontrollers are based on ARM7 core so they have very good performance characteristics. SAM7 microcontrollers differ from other brands with their ability to access memory directly (DMA), so each microcontroller peripheral have distinct two channel controller. LPC series only have AMBA bridge between AHB and LHB.
Main characteristics of AT91SAM7 series:
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very good ratio between performance and poer consumption;
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performance up to 60MIPS;
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ARM/THUM command support;
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32 byte data bus;
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programmable external 8/16/32 byte data bus;
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multiple channel DMA;
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SPI interface – four CS(Chip Select) pins;
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TWI interface;
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Built-in RC generator and PLL;
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Expanded clock generator and power consumption control;
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4 external clock sources;
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Interrupt controller with extended functions;
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Debugging interface;
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RTC with distinct interrupts;
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2 or 3 32bit timer/counters;
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Watch Dog Timer (WDT);
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Power supply from 3.0V to 3.6V;
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5V tolerant I/O;
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power down modes;
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built in Power-On reset and Brown-Out Detector;
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Built in boot-loader for loading Flash via UART or USB port;
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Memory contents protection from reading.
Chips have built in boot-loader that allow downloading firmware to Flash memory via UART or USB. So you can program memory by using simple cable.
For all current list of AT91SAM visit Atmel’s site.
In order to upload program to microcontroller there is flash utility called SAM-BA used which can be found in AT91SAM community site www.at91.com.








