Controller Area Network (CAN) - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 684

Solution: The C program that performs the desired operation is as follows:
#include “c:\iccv712\include\hcs12.h”
#include “c:\iccv712\include\delay.h”
#include “c:\iccv712\include\lcd_util.h”
char *msg1 5 “Sent: “;
char *msg2 5 “Received: “;
void RxISR(void);
void openAD0(void);
void OpenCan1(void);
void MakeBuf(char *pt1, char *pt2);
void snd2can1(char *ptr);
int main(void)
{
char buffer[6]; /* to hold measured voltage */

char buf[16]; /* transmit data buffer */

int temp;

asm( “ldd #_RxISR” ); // pass the interrupt vector of CAN1Rx interrupt

asm( “pshd” ); // “

asm( “ldd #21” ); // place the vector number of CAN1Rx in D

asm( “ldx $EEA4” );
asm( “jsr 0,X” );
openLCD();

/* configure LCD kit */

OpenCan1(); /* configure CAN1 module */

buffer[1] 5 '.'; /* decimal point */

buffer[3] 5 0x20; /* space character */

buffer[4] 5 'V'; /* volt character */

buffer[5] 5 0; /* null character */

openAD0(); /* configure AD0 module */

CAN1RIER 5 0x01; /* enable RXF interrupt only */

asm(“cli”); /* enable interrupt globally */

while(1) {

ATD0CTL5 5 0x87; /* convert AN7, result right-justified */

while(!(ATD0STAT0 & SCF)); /* wait for conversion to complete */

buffer[0] 5 0x30 1 (ATD0DR0*10)/2046; /* integral digit of voltage */

temp 5 (ATD0DR0 * 10) % 2046; /* find the remainder */

buffer[2] 5 0x30 1 (temp * 10)/2046; /* compute the fractional digit */

MakeBuf(&buf[0],&buffer[0]); /* format data for transmission */

snd2can1(&buf[0]); /* send out voltage on CAN bus */

cmd2LCD(0x80); /* set LCD cursor to first row */

putsLCD(msg1); /* output the message “sent: x.y V” */

putsLCD(&buffer[0]); /* “ */

delayby100ms(2); /* wait for messages to arrive for 0.2 s */

}
return 0;
}
/****************************************************************************/
/* The following function formats a buffer into the structure of a CAN transmit buffer so */
/* that it can be copied into any empty transmit buffer for transmission. */
/****************************************************************************/