Книга: Introduction to Microprocessors and Microcontrollers

The software

There are three layers of information that we need to use the registers. Firstly, we need the names and addresses of the files as we met in the register file map in Figure 15.8. The second step is the function of each bit in each register, and this is shown in Appendix A, and finally, an explanation of these functions as we see in Appendix B.

All this data looks daunting but the thing to remember is that we only use one bit at a time and we can ignore the rest.

All PICs and indeed all microprocessors and microcontrollers use binary code and nothing else. To make life easier for us, we use assembly language or a high level language. To use these languages, we need a program which is able to convert them to binary code. For assembly language, the required program is called an assembler and for higher level languages a similar job is done by a compiler.

An assembler is part of the PICSTART PLUS development system but there are other assemblers available that will handle code for all the PICs. The code that we write as the input to the assembler is called ‘source code’ and the code that is supplied by the assembler is called ‘object code’. The object code is really in binary but to make it easier for us, it is usually displayed on the screen in hex.

Important note

As we type in the program we must not leave any spaces in instructions or in the data.

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