Analog-to-Digital Converter - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 619

jsr puts2lcd ; “
ldaa #$C5 ; set LCD cursor position
jsr cmd2lcd ; “
ldx #buf ; output the temperature string
jsr puts2lcd ; “
ldy #2 ; wait for 200 ms
jsr delayby100ms ; “
jmp forever ; continue
; *********************************************************************************
; The following function performs the AD0 configuration.
; *********************************************************************************
openAD0 movb #$E0,ATD0CTL2 ; enable AD0, fast ATD flag clear, stop in wait mode

ldy #2

jsr delayby10us ; wait until AD0 is stabilized

movb #$0A,ATD0CTL3 ; perform one A/D conversion

movb #$25,ATD0CTL4 ; set 4 cycles of sample time, set prescaler

divisor to 12

rts

#include “C:\miniIDE\lcd_util_dragon12.asm”

#include “c:\miniIDE\delay.asm”

msg1 fcc “Temperature 5 ”

dc.b 0

spaces fcc “ ”

dc.b 0

end

The C language version of the program is as follows:
#include “c:\egnu091\include\hcs12.h”

#include “c:\cwHCS12\include\delay.h” //include delay.c in the project

#include “c:\cwHCS12\include\convert.h” //include convert.c in the project

#include “c:\cwHCS12\include\lcd_util.h” //include lcd_util.c in the project

void openAD0(void);

char buf[8];

char *msg1 5 “temperature 5 ”;

char *blanks 5 “ ”;

void main (void)

{

int temp1,temp2;

char sign,fdigit,frem;

char *ptr;

delayby100ms(2); /* wait for LCD kit to initialize */

openlcd(); /* configure LCD kit */

openAD0(); /* configure AD0 module */

cmd2lcd(0x80); /* set cursor to upper left corner */

puts2lcd(msg1); /* output the message “temperature 5 ” */

while(1) {

sign 5 0; /* initialize sign to be positive */

ATD0CTL5 5 0x87; /* start a conversion with result right-justified */

while(!(ATD0STAT0 & SCF)); /* wait until conversion is done */

temp1 5 (ATD0DR0 * 10)/62; /* integer part of temperature */