Julian Paredes

I am having difficulty with ATD on Dragon 12-plus

Discussion created by Julian Paredes on Nov 9, 2009
Latest reply on Nov 16, 2009 by Edgar A Saenz

I am providing the code that I have so far.  Ignore the commented sections because I am not complete with it at the moment.  My goal here is to read from three ports, PAD01 - 03 with the input from an Accelerometer.  In the function for ATD0CTL5 register, I want to read in from each output of the accelerometer, X, Y, and Z which should give me values for each axis.  I am not sure if I wrote it in the code correctly though.  I believe I have it set up for only to read in for PAD02 but I am not sure the proper procedure to write it for three sequences of input.


// accelerometer

#include <mc9s12dp256.h>
#include <stdio.h>
extern int _textmode;

// globals
unsigned char dvalues[3]; // array to hold digitized values from one sequence

// function prototype
void init_ATD0(void);
void load_ADC0interrupt_addr(void);
//load ADC Interrupt vector into vector table
void convert(void);
void ADC0_handler(void);
void delayvar(int multiplier);

// main start here
void main (void){
// unsigned char x=0;
// unsigned char y=0;

/*load_ADC0interrupt_addr( ); // load ADC Interrupt vector into vector table
init_ATD0( );
convert( ); // start conversion

if(lowVx < x-input > highVx)
// printf("Value x=%d\n\r",x-input);
// Send interrupt because tilt is out of range

if(lowVy < y-input > highVy)
// printf("Value y=%d\n\r",y-input);
// Send interrupt because tilt is out of range

} // End while
} // End main

// functions
void delayvar(int multiplier){ // a variable delay: multiplier = 125 is ~5 sec.
unsigned int i,j,k;
// End delayvar
void init_ATD0( ){
ATD0CTL2 = 0x82;
// turn on ADC unit 0, FFCA=1, ASCIE=1(enables ATD0 interrupt) 11000010
delayvar(3); // stabilize ADC unit electronics
ATD0CTL3 = 0x18; // 0001 1000 = 3 conversions/sequence
ATD0CTL4 = 0x8B; // 8-bit resolution, 2 A/D clk/conv., 1 MHz conv. frequency
void convert(void){
ATD0CTL5 = 0x32;
// left justify, unsigned, scan multi, Ch. 2&3, begin sampling, uses AN2-> PAD02
while((ATD0STAT & 0X80) == 0){
dvalues[0] = ATD0DR0H;
dvalues[1] = ATD0DR1H;
dvalues[2] = ATD0DR2H;

void load_ADC0interrupt_addr( ){
asm("ldx #_ADC0_handler");
asm("stx $3e52"); // loads the isr for the ADC0_handler into the...
asm("pulx"); // ..pseudo-vector table

#pragma interrupt_handler ADC0_handler( )

void ADC0_handler(void){ //reads out results from ATD0DRx regs. and stores them
unsigned char *ptr = &dvalues[0]; //variable pointer to storage area 4 results
// puts("\nProgram Interrupted\n\r"); //comment out: causes delay & affects data
asm("sei"); // mask further interrupts until this service finishes
ptr[0] = ATD0DR0H;
ptr[1] = ATD0DR1H;
asm("cli"); // reenable interrupt in order get next sequence