msp430g2xx2 pinosc 01

PinOsc signal feed into TA0CLK.. WDT interval is used // to gate the measurements.. Difference in measurements indicate button touch.. // LEDs flash if input is touched.

//****************************************************************************** // MSP430G2xx2 Demo - Capacitive Touch, Pin Oscillator Method, 1 button

//

// Description: Basic 1-button input using the built-in pin oscillation feature // on GPIO input structure PinOsc signal feed into TA0CLK WDT interval is used

// to gate the measurements Difference in measurements indicate button touch // LEDs flash if input is touched

//

// ACLK = VLO = 12kHz, MCLK = SMCLK = 1MHz DCO

//

// MSP430G2xx2

//

-// /|\| XIN|-// | | |

// |RST XOUT|-// | |

// | P1.1|< Capacitive Touch Input 1 // | |

// LED 2 < |P1.6 |

// | |

// LED 1 < |P1.0 |

// | |

// | |

// // Brandon Elliott/D Dang // Texas Instruments Inc // November 2010 // Built with IAR Embedded Workbench Version: 5.10 //****************************************************************************** #include "msp430g2452.h" /* Define User Configuration values */ /* -*/

/* Defines WDT SMCLK interval for sensor measurements*/

#define WDT_meas_setting (DIV_SMCLK_512)

/* Defines WDT ACLK interval for delay between measurement cycles*/

#define WDT_delay_setting (DIV_ACLK_512)

/* Sensor settings*/

#define KEY_LVL 220 // Defines threshold for a key press /*Set to ~ half the max delta expected*/

/* Definitions for use with the WDT settings*/

#define DIV_ACLK_32768 (WDT_ADLY_1000) // ACLK/32768

#define DIV_ACLK_8192 (WDT_ADLY_250) // ACLK/8192

#define DIV_ACLK_512 (WDT_ADLY_16) // ACLK/512

#define DIV_ACLK_64 (WDT_ADLY_1_9) // ACLK/64

#define DIV_SMCLK_32768 (WDT_MDLY_32) // SMCLK/32768

#define DIV_SMCLK_8192 (WDT_MDLY_8) // SMCLK/8192

#define DIV_SMCLK_512 (WDT_MDLY_0_5) // SMCLK/512

#define DIV_SMCLK_64 (WDT_MDLY_0_064) // SMCLK/64

#define LED_1 (0x01) // P1.0 LED output

#define LED_2 (0x40) // P1.6 LED output

// Global variables for sensing

unsigned int base_cnt, meas_cnt;

int delta_cnt;

char key_pressed;

int cycles;

/* System Routines*/

void measure_count(void); // Measures each capacitive sensor void pulse_LED(void); // LED gradient routine

/* Main Function*/

void main(void)

{

unsigned int i,j;

WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

BCSCTL1 = CALBC1_1MHZ; // Set DCO to 1MHz

DCOCTL = CALDCO_1MHZ;

BCSCTL3 |= LFXT1S_2; // LFXT1 = VLO

IE1 |= WDTIE; // enable WDT interrupt

P2SEL = 0x00; // No XTAL

P1DIR = LED_1 + LED_2; // P1.0 & P1.6 = LEDs

P1OUT = 0x00;

bis_SR_register(GIE); // Enable interrupts

measure_count(); // Establish baseline capacitance base_cnt = meas_cnt;

for(i=15; i>0; i ) // Repeat and avg base measurement {

measure_count();

base_cnt = (meas_cnt+base_cnt)/2;

}

/* Main loop starts here*/

while (1)

{

j = KEY_LVL;

key_pressed = 0; // Assume no keys are pressed

measure_count(); // Measure all sensors

delta_cnt = base_cnt - meas_cnt; // Calculate delta: c_change

/* Handle baseline measurment for a base C decrease*/

if (delta_cnt < 0) // If negative: result increased { // beyond baseline, i.e cap dec base_cnt = (base_cnt+meas_cnt) >> 1; // Re-average quickly

delta_cnt = 0; // Zero out for pos determination }

if (delta_cnt > j) // Determine if each key is pressed { // per a preset threshold

j = delta_cnt;

key_pressed = 1; // key pressed

}

else

key_pressed = 1;

/* Delay to next sample, sample more slowly if no keys are pressed*/

if (key_pressed)

{

BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_0; // ACLK/(0:1,1:2,2:4,3:8)

cycles = 20;

}

else

{

cycles ;

if (cycles > 0)

BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_0; // ACLK/(0:1,1:2,2:4,3:8)

else

{

BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_3; // ACLK/(0:1,1:2,2:4,3:8)

cycles = 0;

}

}

WDTCTL = WDT_delay_setting; // WDT, ACLK, interval timer

/* Handle baseline measurment for a base C increase*/

if (!key_pressed) // Only adjust baseline down

{ // if no keys are touched

base_cnt = base_cnt - 1; // Adjust baseline down, should be } // slow to accomodate for genuine pulse_LED(); // changes in sensor C

bis_SR_register(LPM3_bits);

}

} // End Main

/* Measure count result (capacitance) of each sensor*/

/* Routine setup for four sensors, not dependent on NUM_SEN value!*/

void measure_count(void)

{

TA0CTL = TASSEL_3+MC_2; // TACLK, cont mode

TA0CCTL1 = CM_3+CCIS_2+CAP; // Pos&Neg,GND,Cap

/*Configure Ports for relaxation oscillator*/

/*The P2SEL2 register allows Timer_A to receive it's clock from a GPIO*/ /*See the Application Information section of the device datasheet for info*/ P1DIR &= ~ BIT1; // P1.1 is the input used here

P1SEL &= ~ BIT1;

P1SEL2 |= BIT1;

/*Setup Gate Timer*/

WDTCTL = WDT_meas_setting; // WDT, ACLK, interval timer

TA0CTL |= TACLR; // Clear Timer_A TAR

bis_SR_register(LPM0_bits+GIE); // Wait for WDT interrupt

TA0CCTL1 ^= CCIS0; // Create SW capture of CCR1

meas_cnt = TACCR1; // Save result

WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

P1SEL2 &= ~BIT1;

}

void pulse_LED(void)

{

if(key_pressed)

{

P1OUT ^= LED_1 + LED_2;

}else{

P1OUT = 0;

}

}

/* Watchdog Timer interrupt service routine*/

#pragma vector=WDT_VECTOR

interrupt void watchdog_timer(void)

{

TA0CCTL1 ^= CCIS0; // Create SW capture of CCR1

bic_SR_register_on_exit(LPM3_bits); // Exit LPM3 on reti

}