LaunchPad例程源代码

//****************************************************************************** // MSP430G2xx3 Demo - Capacitive Touch, Pin Oscillator Method, 5 buttons, UART // // Description: Basic 8-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. // Pins used for inputs listed in the diagram below. // After each scan, one UART byte identifying the key# being pressed is // transmitted via TimerA UART at port pin P1.1. // // // ACLK = VLO = 12kHz, MCLK = SMCLK = 1MHz DCO // // MSP430G2xx3 // ----------------- // /|\| | // | | | // --|RST | // | | // input 1-->|P2.0 P1.1|--> TA UART output TXD // | | // input 2-->|P2.1 | // | | // input 3-->|P2.2 | // | | // input 4-->|P2.3 | // | | // input 5-->|P2.4 | // | | // ----------------- All five inputs are capacitive touch inputs // // Brandon Elliott/D. Dang // Texas Instruments Inc. // November 2010 // Built with IAR Embedded Workbench Version: 5.10 //****************************************************************************** #include "msp430g2553.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 NUM_SEN 5 // Total number of sensors #define KEY_LVL 190 // 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 /* Global variables for sensing*/ unsigned int base_cnt[NUM_SEN]; unsigned int meas_cnt[NUM_SEN]; int delta_cnt[NUM_SEN]; unsigned char key_press[NUM_SEN]; char key_pressed; int cycles; const unsigned char electrode_bit_P2[NUM_SEN]={BIT0, BIT1, BIT2, BIT3, BIT4}; /* System Routines*/ void measure_count(void); // Measures each capacitive sensor void TX_Byte (char); // Transmits key pressed via UART /* 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 __bis_SR_register(GIE); // Enable interrupts measure_count(); // Establish baseline capacitance for (i = 0; i<NUM_SEN; i++) base_cnt[i] = meas_cnt[i]; for(i=15; i>0; i--) // Repeat and avg base measurement { measure_count(); for (j = 0; j<NUM_SEN; j++) base_cnt[j] = (meas_cnt[j]+base_cnt[j])/2; } /* Main loop starts here*/ while (1) { j = KEY_LVL; measure_count(); // Measure all sensors for (i = 0; i<NUM_SEN; i++) { /* Handle baseline measurment for a base C decrease*/ if (base_cnt[i] < meas_cnt[i]) // If negative: result increased { // beyond baseline, cap decreased base_cnt[i] = (base_cnt[i]+meas_cnt[i]) >> 1; // Re-average up quickly delta_cnt[i] = 0; // Zero out for position determination } else { delta_cnt[i] = base_cnt[i] - meas_cnt[i]; // Calculate delta: c_change } if (delta_cnt[i] > j) // Determine if each key is pressed { // per a preset threshold key_press[i] = 1; // Specific key pressed j = delta_cnt[i]; key_pressed = i+1; // key pressed } else key_press[i] = 0; } /* Delay to next sample, sample more slowly if no keys are pressed*/ if (key_pressed) { TX_Byte(key_pressed); BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_0; // ACLK/(0:1,1:2,2:4,3:8) cycles = 20; } else { cycles--; if (cycles > 0) // ACLK/(0:1,1:2,2:4,3:8) BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_0; else { // ACLK/(0:1,1:2,2:4,3:8) BCSCTL1 = (BCSCTL1 & 0x0CF) + DIVA_3; cycles = 0; } } WDTCTL = WDT_delay_setting; // WDT, ACLK, interval timer /* Handle baseline measurment for a base C increase*/ if (!key_pressed) // adjust down if no keys touched { for (i = 0; i<NUM_SEN; i++) base_cnt[i] = base_cnt[i] - 1; // Adjust baseline down, should be } // slow to accomodate for genuine __bis_SR_register(LPM3_bits); // changes in sensor C } } // End Main /* Measure count result (capacitance) of each sensor*/ /* Routine setup for four sensors, not dependent on NUM_SEN value!*/ void measure_count(void) { char i; TA0CTL = TASSEL_3+MC_2; // TACLK, cont mode TA0CCTL1 = CM_3+CCIS_2+CAP; // Pos&Neg,GND,Cap for (i = 0; i<NUM_SEN; i++) { /*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*/ P2DIR &= ~ electrode_bit_P2[i]; P2SEL &= ~ electrode_bit_P2[i]; P2SEL2 |= electrode_bit_P2[i]; // input oscillation feeds TACLK /* 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[i] = TACCR1; // Save result WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer P2SEL2 &= ~electrode_bit_P2[i]; } TA0CTL = 0; // Stop Timer_A } /* 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 } /* UART Information: Conditions for 9600 Baud SW TX-only UART, SMCLK = 8MHz */ #define Bitime 0x0341 // x us bit length ~ x baud #define TXD BIT1 // TXD on P1.1 unsigned int RXTXData; unsigned char BitCnt; void TX_Byte (char TX_DATA) { BCSCTL1 = CALBC1_8MHZ; // Set DCO to 8MHz DCOCTL = CALDCO_8MHZ; TX_DATA += '0';