Page 388 - Programming Microcontrollers in C

The Monitor Program 373

The final portion of this header file is a collection of all of the
function prototypes needed for this program. When this program is
moved from the DOS-based system to the microcontroller-based
system, it is necessary to remove the first line of the above header
file. There are three functions found in the standard input/output
library that will be rewritten for this program. These functions are
inituart(), putchar(), getchar() and puts(). The
function prototypes for these functions are included and will be
discarded when the parameter DOS is not defined.
The monitor program is shown below in Listing 7-12. In the
header file above, a structure was typedefed as an Epro. This
structure is the size of the EEPROM on board the chip. An external
instance of an Epro, named able, is created and it will be used as
a destination for all of the nonvolatile stored data in the program.
Inside the main() program, two arrays are created: one array to
store the name entered from the keyboard and the other to store the
phone number entered from the keyboard. Also, the external structure
will be passed around from function to function via a pointer. This
pointer is created and initialized to the structure able. Also, if the
parameter DOS is not defined, the function inituart() is executed
to enable the use of the UART on the microcontroller when it is needed.
After this initialization is completed, control is passed into a
FOREVER loop where it will remain so long as the computer
continues to run. Within this loop, an input is read from the keyboard.
It is assumed that the keyboard input will read in the data and return
ASCII characters. If the system is a part of a telephone or a PDA, the
input routine will have to read in the keyboard data and convert it to
the correct ASCII value prior to its use in the following program.
Therefore, getchar() in the following program can be a function
that reads data from a serial port or some other program that will
input the data from whatever keyboard is used with the system. Inside
of the FOREVER loop, a character is read in and then it is tested in
a switch()/case sequence. The current test values are ‘n’, ‘a’,
‘s’, and ‘r’. These inputs are commands that determine what the
program will do:

Command Action
n Read in a number/name sequence, encode these
data and save them in the nonvolatile array.