/* --COPYRIGHT--,BSD_EX * Copyright (c) 2014, Texas Instruments Incorporated * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * * Neither the name of Texas Instruments Incorporated nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ******************************************************************************* * * MSP430 CODE EXAMPLE DISCLAIMER * * MSP430 code examples are self-contained low-level programs that typically * demonstrate a single peripheral function or device feature in a highly * concise manner. For this the code may rely on the device's power-on default * register values and settings such as the clock configuration and care must * be taken when combining code from several examples to avoid potential side * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware * for an API functional library-approach to peripheral configuration. * * --/COPYRIGHT--*/ //****************************************************************************** // MSP430FR231x 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 TB0CLK. WDT interval is used // to gate the measurements. Difference in measurements indicate button touch. // LEDs flash if input is touched. // // ACLK = REFO = 32kHz, MCLK = SMCLK = 1MHz DCO // // MSP430FR2311 // ----------------- // /|\| XIN|- // | | | // --|RST XOUT|- // | | // | P1.1|<--Capacitive Touch Input 1 // | | // | | // | | // LED 1 <--|P1.0 | // | | // | | // // Darren Lu // Texas Instruments Inc. // Oct. 2015 // Built with IAR Embedded Workbench v6.30 & Code Composer Studio v6.1 //****************************************************************************** #include /* 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 (0x01) // P1.0 LED output // Global variables for sensing unsigned int base_cnt, meas_cnt; int delta_cnt; char key_pressed; /* System Routines*/ void measure_count(void); // Measures each capacitive sensor void pulse_LED(void); // LED gradient routine int main( void ) { unsigned int i,j; WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer PM5CTL0 &= ~LOCKLPM5; SFRIE1 |= WDTIE; // enable WDT interrupt P1DIR = LED; // P1.0 = LED 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 = 0; /* Delay to next sample */ 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) { TB0CTL = TBSSEL_3 + MC_2; // INCLK, cont mode TB0CCTL1 = CM_3 + CCIS_2 + CAP; // Pos&Neg,GND,Cap /*Configure Ports for relaxation oscillator*/ CAPTIOCTL |= CAPTIOEN + CAPTIOPOSEL0 + CAPTIOPISEL0; //P1.1 /*Setup Gate Timer*/ WDTCTL = WDT_meas_setting; // WDT, ACLK, interval timer TB0CTL |= TBCLR; // Clear Timer_B TBR __bis_SR_register(LPM0_bits+GIE); // Wait for WDT interrupt TB0CCTL1 ^= CCIS0; // Create SW capture of CCR1 meas_cnt = TB0CCR1; // Save result WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer CAPTIOCTL = 0; } void pulse_LED(void) { if(key_pressed) { P1OUT ^= LED; } else { P1OUT = 0; } } /* Watchdog Timer interrupt service routine*/ #if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__) #pragma vector=WDT_VECTOR __interrupt void watchdog_timer(void) #elif defined(__GNUC__) void __attribute__ ((interrupt(WDT_VECTOR))) watchdog_timer (void) #else #error Compiler not supported! #endif { TB0CCTL1 ^= CCIS0; // Create SW capture of CCR1 __bic_SR_register_on_exit(LPM3_bits); // Exit LPM3 on reti }