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#include <stdint.h>
#include "msp430.h"
#define WHEEL_DIR P8DIR
#define WHEEL_OUT P8OUT
#define WHEEL_EN BIT0
#define ADC_PORT_SEL P6SEL
#define ADC_INPUT_A5 BIT5
unsigned int positionData;
unsigned int positionDataOld;
/******************************************************************************/
void Wheel_init(void)
{
WHEEL_DIR |= WHEEL_EN;
WHEEL_OUT |= WHEEL_EN; // Enable wheel
ADC12CTL0 = ADC12SHT02 + ADC12ON; // Sampling time, ADC12 on
ADC12CTL1 = ADC12SHP; // Use sampling timer
ADC12MCTL0 = ADC12INCH_5; // Use A5 (wheel) as input
ADC12CTL0 |= ADC12ENC; // Enable conversions
ADC_PORT_SEL |= ADC_INPUT_A5; // P6.5 ADC option select (A5)
}
/***************************************************************************/
uint8_t Wheel_getPosition(void)
{
uint8_t position = 0;
Wheel_getValue();
//determine which position the wheel is in
if (positionData > 0x0806)
position = 7 - (positionData - 0x0806) / 128; //scale the data for 8 different positions
else
position = positionData / 260;
return position;
}
/**************************************************************************/
int Wheel_getValue(void)
{
//measure ADC value
ADC12IE = 0x01; // Enable interrupt
ADC12CTL0 |= ADC12SC; // Start sampling/conversion
__bis_SR_register(LPM0_bits + GIE); // LPM0, ADC12_ISR will force exit
ADC12IE = 0x00; // Disable interrupt
//add hysteresis on wheel to remove fluctuations
if (positionData > positionDataOld)
if ((positionData - positionDataOld) > 10)
positionDataOld = positionData; //use new data if change is beyond
// fluctuation threshold
else
positionData = positionDataOld; //use old data if change is not beyond
// fluctuation threshold
else
if ((positionDataOld - positionData) > 10)
positionDataOld = positionData; //use new data if change is beyond
// fluctuation threshold
else
positionData = positionDataOld; //use old data if change is not beyond
// fluctuation threshold
return positionData;
}
/***************************************************************************/
void Wheel_disable(void)
{
WHEEL_OUT &= ~WHEEL_EN; //disable wheel
ADC12CTL0 &= ~ADC12ENC; // Disable conversions
ADC12CTL0 &= ~ADC12ON; // ADC12 off
}
/******************************************************************************/
void Wheel_enable(void)
{
WHEEL_OUT |= WHEEL_EN; //enable wheel
ADC12CTL0 |= ADC12ON; // ADC12 on
ADC12CTL0 |= ADC12ENC; // Enable conversions
}
/******************************************************************************/
int main(void)
{
P1DIR=0x3F;
Wheel_enable();
Wheel_init();
while(1)
{
Wheel_getValue();
switch(positionData)
{
case 0:P1OUT=0x01;break;
case 1:P1OUT=0x02;break;
case 2:P1OUT=0x04;break;
case 3:P1OUT=0x08;break;
case 4:P1OUT=0x10;break;
case 5:P1OUT=0x20;break;
}
}
}
/******************************************************************************/
#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
{
switch (__even_in_range(ADC12IV, ADC12IV_ADC12IFG15))
{
// Vector ADC12IV_NONE: No interrupt
case ADC12IV_NONE:
break;
// Vector ADC12IV_ADC12OVIFG: ADC overflow
case ADC12IV_ADC12OVIFG:
break;
// Vector ADC12IV_ADC12TOVIFG: ADC timing overflow
case ADC12IV_ADC12TOVIFG:
break;
// Vector ADC12IV_ADC12IFG0: ADC12IFG0:
case ADC12IV_ADC12IFG0:
positionData = ADC12MEM0; // ADC12MEM = A0 > 0.5AVcc?
__bic_SR_register_on_exit(LPM0_bits); // Exit active CPU
break;
// Vector ADC12IV_ADC12IFG1: ADC12IFG1
case ADC12IV_ADC12IFG1:
break;
// Vector ADC12IV_ADC12IFG2: ADC12IFG2
case ADC12IV_ADC12IFG2:
break;
// Vector ADC12IV_ADC12IFG3: ADC12IFG3
case ADC12IV_ADC12IFG3:
break;
// Vector ADC12IV_ADC12IFG4: ADC12IFG4
case ADC12IV_ADC12IFG4:
break;
// Vector ADC12IV_ADC12IFG5: ADC12IFG5
case ADC12IV_ADC12IFG5:
break;
// Vector ADC12IV_ADC12IFG6: ADC12IFG6
case ADC12IV_ADC12IFG6:
break;
// Vector ADC12IV_ADC12IFG7: ADC12IFG7
case ADC12IV_ADC12IFG7:
break;
// Vector ADC12IV_ADC12IFG8: ADC12IFG8
case ADC12IV_ADC12IFG8:
break;
// Vector ADC12IV_ADC12IFG9: ADC12IFG9
case ADC12IV_ADC12IFG9:
break;
// Vector ADC12IV_ADC12IFG10: ADC12IFG10
case ADC12IV_ADC12IFG10:
break;
// Vector ADC12IV_ADC12IFG11: ADC12IFG11
case ADC12IV_ADC12IFG11:
break;
// Vector ADC12IV_ADC12IFG12: ADC12IFG12
case ADC12IV_ADC12IFG12:
break;
// Vector ADC12IV_ADC12IFG13: ADC12IFG13
case ADC12IV_ADC12IFG13:
break;
// Vector ADC12IV_ADC12IFG14: ADC12IFG14
case ADC12IV_ADC12IFG14:
break;
// Vector ADC12IV_ADC12IFG15: ADC12IFG15
case ADC12IV_ADC12IFG15:
break;
default:
break;
}
}
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