ARM7 Introduction

ARM7TDMI-S is a general-purpose 32-bit microprocessor, which offers high performance and very low power consumption. The ARM architecture is based on Reduced Instruction Set Computer (RISC) principles, and the instruction set and related decode mechanism are much simpler than those of microprogrammed Complex Instruction Set Computers.

  • Pipeline techniques are employed so that all parts of the processing and memory systems can operate continuously.
  • Typically, while one instruction is being executed, its successor is being decoded, and a third instruction is being fetched from memory.
  • The ARM7TDMI-S processor also employs a unique architectural strategy known as THUMB.
  • THUMB is that of a super-reduced instruction set.Essentially, the ARM7TDMI-S processor has two instruction sets:
    1. The standard 32-bit ARM instruction set.
    2. A 16-bit THUMB instruction set.
  • The THUMB set 16-bit instruction length allows it to approach twice the density of standard ARM code while retaining most of the ARM performance advantage over a traditional 16-bit processor using 16-bit registers.
  • THUMB code is able to provide up to 65% of the code size of ARM, and 160% of the performance of an equivalent ARM processor connected to a 16-bit memory system.
  • The LPC21xx is based on a 16/32bit ARM7TDMI-S CPU with real-time emulation.
  • A 128-bit wide internal memory interface.
  • A 16-bit Thumb Mode reduces code by more than 30% with minimal performance penalty with compact 64 and 144 pin packages.
  • It has low power consumption and various 32-bit timers..
  • 12 external interrupt pins.
  • It consists of four channel 10-bit ADC -> 46 GPIOs (64 pin packages) and 8-channel 10-bit ADC -> 112 GPIOs (144 pin package).
  • These microcontrollers are particularly targeted for industrial control, medical systems, access control, and point-of-sale.
  • Two-port
    1. Port 0 :32 pins,
    2. Port 1 :32 pins.
  • It has 32 input and output pins.
  • The port P1 has 32 pins in that only 16pins are used as input and output pin and other pins are dedicated to a special purpose.

Pin Diagram