Page 397 - Programming Microcontrollers in C

382 Chapter 7 Advanced Topics

#endif
/* Start the linked list */
NEXT_OPEN = 3;/* next open entry in the list */
START_OF_LIST =0;/* start of the list */
LIST_ENTRIES=0;/* number of entries in the list */
epro->header[0].dataindex=NEXT_OPEN;/* start
the list */
for(i=0;i<DLEN;i++)
epro->header[i].next=END;

}
Listing 7-16: The Reset Function

Input/Output Functions

There are three input/output functions that are usually found in
the standard I/O library that we will replace with microcontroller
specific code here. These functions are putchar(), getchar(),
and puts(). In the first two instances, rather than sending and
receiving data from devices like stdout and stdin, all output
will go to the serial port on the HC12 and input will come likewise
from the serial port. Therefore, these routines will have to be written
from scratch. In addition to the direct input/output functions, an
initialization function that enables the serial port will be needed. This
function must set the bit rate for the serial port and enable both the
UART transmitter and receiver. This function is as follows:

#include “hc12.h”

#define BAUD9600 52

#define BAUDREG *(BYTE *)&SC0BDL

void inituart(void)
{
BAUDREG=BAUD9600; /* Set the bit rate */
SC0CR2.TE=ON; /* turn on transmitter */
SC0CR2.RE=ON; /* and the receiver */
}