ARM7TDMI™

The ARM7TDMI™ embedded microcontroller core is a member of the AdvancedRISC Machines (ARM®) family of general purpose 32-bit microprocessors, which offerhigh performance and very lower power consumption. ARM7TDMI™ outstanding feature is the16-bit Thumb® subset of the most commonly used 32-bit instructions. These areexpanded at run time with no degradation of system performance. ARM7TDMI™ gives 16-bitcode density (saving memory area and cost) coupled with 32-bit processorperformance.

The ARM ARM7TDMI™architecture is based on Reduced Instruction Set Computer (RISC) princi-ples, and the instruction set and related decode mechanism are much simpler thanthose of microprogrammed Complex Instruction Set Computers. ARM7TDMI™ simplicity resultsin a high instruction throughput and impressive real-time interrupt response from asmall and cost-effective chip.

Pipelining ARM7TDMI™ is employed so that all parts of the processing and memory systems canoperate continuously. Typically, while one instruction is being executed, its successoris being decoded, and a third instruction is being fetched from memory.

The ARM ARM7TDMI™memory interface has been designed to allow the performance potential tobe realized without incurring high costs in the memory system. Speed-critical controlsignals are pipelined to allow system control functions to be implemented in standardlow-power logic, and these control signals facilitate the exploitation of the fast localaccess modes offered by industry standard dynamic RAMs.

The ARM ARM7TDMI™memory interface is also ideally suited to interfacing, either on-chip or off-chip, with Atmel's Flash memory blocks. These give the benefits of in-system pro-grammability and security, reducing time-to-market and system cost.

The ARM7TDMI core is supported by an extensive range of application developmenttools. These are fully described in the AT91Business Partners section of Atmels'sWeb site (www.atmel.com).