Number System

In this section we will the discuss the basic requirements to write a program i.e to declare the bit stream

Whenever we write the program.

An ARM 7 controller is a 32-bit microcontroller hence every bit stream i.e handled by the controller or the instructions given to it are of 32-bit.

In order to write this 32-bit stream as is it long we will follow three easy ways to declare the stream which are

1. Binary representation.

2. Hexadecimal representation.

3. Decimal representation.

1         Binary representation:

 In this method during the instructions given the bit stream is declared by giving overall 32-bits as seen below.

Ex: in order to set a value of 1 to P0.0 we will use the following instruction.

              IOSET=0b00000000000000000000000000000001;

             The b represents it is a binary presentation.

              Similarly in order to clear the same pin we will use following instruction

              IOCLR=0b00000000000000000000000000000001;

1

              Hexa decimal representation:

   In this method during giving instructions the bit stream is declared by giving

   Over all 32 bits in hexa decimal number which is relatively easy compared to binary representation.

   Ex: in order to set a value of one to the pin from P0.0 to P0.3 we will use following instruction

                 IOSET= 0X0000000F;

                The first X represents it is a hexa representation.

                

Similarly in order to clear we will use following 

IOCLR=0x0000000F

1

            Decimal representation:

In this method instructions are declared by giving a decimal number as following.

In order to set the last bits P0.0 to P0.3 we will use the following instruction

IOSET=15;

Similarly for the clearing purpose we will use

IOCLR=15;

In this entire ARM 7 section we will follow the hexa decimal representation as it is little convenient comparing both other. The convenience will be explained later during programming.