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Overview of ARM7 LPC 2148
ARM7 Overview
• On April 26th, 1985, ARM was first developed by Acorn Computers in Cambridge, England.
• ARM or Advanced RISC Machine, uses a 32-bit RISC (Reduced Instruction Set Computer) processor.
• The CPU at the heart of the LPC2000 family is an ARM7.
• The ARM7 is a RISC computer with a small instruction set and consequently a small gate count.
• It has high performance, low power consumption and it takes a small amount of the available silicon die area.
• In ARM7 a three-stage pipeline is used.
 ARM7 Registers
 The ARM7 is a load-and-store architecture.
 The central set of registers are a bank of 16 user registers R0 – R15.
 Each of these registers is 32 bits wide and R0 – R12 are user registers in that they do not have any specific other function.
 ARM vs THUMB Instruction Set
• The ARM7 CPU has two instruction sets:
 ARM instruction set which has 32-bit wide instructions.
 THUMB instruction set which has 16-bit wide instructions.
• The THUMB instruction set is a compressed form of the ARM instruction set.
• By compiling code in the THUMB instruction set we can get a space saving of 30%, while the same code compiled as ARM code will run 40% faster.
ARM Instruction THUMB Instruction
ADD R0, R0,R1 ADD R0,R1 R0 = R0+R1

 Big-endian and Little-endian
 The ARM7 is designed to operate as a big-endian or little-endian processor.
 The LPC2000 family fixes the endianess of the processor as little endian (i.e. MSB at highest bit address).
• Philips LPC2148 microcontroller operates on 60 MHz clock.
• It has 512 KB program Flash memory and 40 KB SRAM.
• LPC2148 uses ARM7TDMI as its core.
• The T stands for Thumb instruction set.
• The D stand for ARM7 offers on-chip debug support.
• The M means that the CPU contains a hardware multiply unit.
• The I means the debug hardware allows breakpoints and watchpoints to be set.
 Read Toggle Switches using ARM
 32 x 32 Multiplication in ALP using ARM
 Common files that are used while Programming
 LCD.S
 It contains all the necessary subroutines while using the LCD
display like to initialize LCD, display character, display word etc.
 LPC214X.H
 It is a common header file for 2141/42/46 microcontrollers
provided by manufacturer Philips.
 It contains the address for all the internal blocks and special
registers such as Timers, Serial ports etc.
eg. # define IODIR0 0XE0028008
 Vector.S
 It contains the start up code.
 This file is used to initialize the values of PC,SP,Timers etc.
 Flash.ld
 It is a Linker file for running the code from flash memory.
 File named ”Flash.ld” which is Script File uses to keep the beginning and the end of default value with Flash Memory size.