![]() Main is a special function that contains the main program block, within which all lower-level functions are contained. All program blocks are enclosed by braces, allowing a multilevel hierarchical structure. The main program starts with the key words void main() and is enclosed between curly brackets, or braces, as they are officially known. Any information needed by the function, the function parameter(s), is inserted into the parentheses. The general form of the C function is function_name(). This particular function is one of a set of library functions of the form output_x(n), where x is the port number (A–E), and n is the output value (0–255). This statement is a function call, which means the compiler gets the machine code for this operation from the standard set of built-in functions supplied with the compiler. All statements are terminated with a semicolon. This means output the number 255 10 as a binary code to Port D of the chip, setting all pins high (obviously, any number between 0 and 255 results in a corresponding output bit combination). The main program contains just one statement, output_D(255). Bates, in Programming 8-bit PIC Microcontrollers in C, 2008 Program Analysis It follows that the “And” rule operates under a similar premise, though all the delimited codes must return TRUE if the agent is to continue executing. However, if the last code to be evaluated (e.g., ) yields a FALSE outcome, then the MA terminates. For example, an Or rule construct O executes until the outcome of one of these segments yields a TRUE outcome. In addition to this, the And/ Or rules control an MA's execution flow by verifying the outcome of the delimited codes within square brackets. Consequently, the codes within the repeat rule execute until a certain condition evaluation fails. The cell data structure is indicated by curly brackets, i.e., ). We now introduce the cell array structure which allows a more complex data structure. Previous sections discussed the use of numerical and non-numerical data. George Lindfield, John Penny, in Numerical Methods (Fourth Edition), 2019 1.20 Data Structures in Matlab While loops can be nested inside one another. An example is given below, where the program waits until variable CLK becomes 0: For example, to wait until a button is pressed. Such a loop is commonly used in microcontroller applications to wait for certain action to be completed. It is possible to have a while loop with no statements. In the following example i is initialized to 0, but is never changed inside the loop and is therefore always less than 10. It is important to realize that the condition specified at the beginning of the loop should be satisfied inside the loop, otherwise an endless loop is formed. The loop terminates when i becomes equal to 10. Here, at the beginning of the loop, i is equal to 0, which is less than 10 and therefore the loop starts. An example is given below where the statements inside the while loop execute 10 times: Notice that if the condition is FALSE on entry to the loop, then the loop never executes. Here, the loop enclosed by the curly brackets executes as long as the specified condition evaluates to TRUE. The format of this statement is as follows: While statement is another statement that can be used to create loops in programs. C Programming for 32-Bit PIC Microcontrollersĭogan Ibrahim, in Designing Embedded Systems with 32-Bit PIC Microcontrollers and MikroC, 2014 while Statement
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