Page 389 - Programming Microcontrollers in C

374 Chapter 7 Advanced Topics

r Reset the system and erase the EEPROM array
which destroys all stored information.
s Display all stored data in sequence.
a Display the next stored number and name.

The functions that perform these various operations are discussed in
the following sections. All of the case choices merely call the required
function with the exception of the ‘n’ command. The ‘n’ command
calls the function get() twice to read in the number followed by
the name. These data are stored in the designated arrays and the two
arrays containing the data are passed to the function saveit()
along with a pointer to the nonvolatile structure able. Otherwise, the
program remains in the FOREVER loop, exiting the loop only to
execute commands entered from the keyboard.

/* monitor.c is the initial program that is being
developed to use on the HC12.The end product
can be used as a part of a PDA or a telephone
that requires that you enter names and phone
numbers.These entries are to be saved in
nonvolatile RAM such as flash or EEPROM,
perhaps both. In order to save memory space,
encoding of the stored data will be used. All
numbers will be stored as BCD digits and
letters will be stored as a Huffman code.It
is assumed that letter fields and number
fields will not contain mixed data.
The code in this program is programmed
for the DOS based system. No printf is used,
but other i/o functions are used as needed. It
is assumed now that any input will be
received as serial data from a serial port
on the chip.
This particular program reads data in
from the keyboard. The numeric field is
written first and the alpha field is written
second. If it is a numeric field, the data
are converted to BCD and stored in an
allocated memory field. If it is alpha data,
it is written to an allocated memory field.