Original question:
Part Number: MSP430FR2311
I am looking for a simple implementation example for creating a capacitance button for a MSP430FR2311. Can you point me to a reference design?
Hi Jim,
TI recommend to use MSPFR25xx and MSP430FR26xx CapTIvate device for capacitive touch application.
But if you insist on using FR2311, here are 2 code examples for you reference.
/* --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 <msp430.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 (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
}
/* --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, 4-buttons
//
// Description: Basic 4-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.
// LED flash if input is touched.
//
// Input 1: LED1 (LED2 off)
// Input 2: LED2 (LED1 off)
// Input 3: Both LEDs on
// Input 4: Both LEDs flash on/off
//
// ACLK = VLO = 32kHz, MCLK = SMCLK = 1MHz DCO
//
// MSP430FR2311
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// | |
// | P2.2|<--Capacitive Touch Input 1
// | |
// LED 2 <--|P1.1 P2.3|<--Capacitive Touch Input 2
// | |
// LED 1 <--|P1.0 P2.4|<--Capacitive Touch Input 3
// | |
// | P2.5|<--Capacitive Touch Input 4
//
// Darren Lu
// Texas Instruments Inc.
// Oct. 2015
// Built with IAR Embedded Workbench v6.30 & Code Composer Studio v6.1
//******************************************************************************
#include <msp430.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 4 // Defines number of sensors
#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 (BIT0) // P1.0 LED output
#define LED_2 (BIT1) // P1.1 LED output
// 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;
const unsigned char electrode_bit[NUM_SEN]={BIT2, BIT3, BIT4, BIT5};
/* System Routines*/
void measure_count(void); // Measures each capacitive sensor
void pulse_LED(void); // LED gradient routine
void pinosc_channel_select(unsigned char PORT, unsigned char PIN);
int main( void )
{
unsigned int i,j;
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
PM5CTL0 &= ~LOCKLPM5;
SFRIE1 |= WDTIE; // enable WDT interrupt
P1DIR |= LED_1 + LED_2; // P1.0 & P1.1 = LEDs
P1OUT &= ~(LED_1 + LED_2);
__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;
key_pressed = 0; // Assume no keys are pressed
measure_count(); // Measure all sensors
for (i = 0; i<NUM_SEN; i++)
{
delta_cnt[i] = base_cnt[i] - meas_cnt[i]; // Calculate delta: c_change
/* Handle baseline measurment for a base C decrease*/
if (delta_cnt[i] < 0) // If negative: result increased
{ // beyond baseline, i.e. cap dec
base_cnt[i] = (base_cnt[i]+meas_cnt[i]) >> 1; // Re-average quickly
delta_cnt[i] = 0; // Zero out for pos determination
}
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 */
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
for (i = 0; i<NUM_SEN; i++)
base_cnt[i] = base_cnt[i] - 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)
{
unsigned char i;
TB0CTL = TBSSEL_3 + MC_2; // INCLK, cont mode
TB0CCTL1 = CM_3 + CCIS_2 + CAP; // Pos&Neg,GND,Cap
for (i = 0; i<NUM_SEN; i++)
{
/*Configure Ports for relaxation oscillator*/
pinosc_channel_select(2, electrode_bit[i]);
/*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[i] = TB0CCR1; // Save result
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
CAPTIOCTL = 0;
}
}
void pinosc_channel_select(unsigned char PORT, unsigned char PIN)
{
CAPTIOCTL = 0;
switch(PORT)
{
case 1: CAPTIOCTL |= CAPTIOPOSEL0; break;
case 2: CAPTIOCTL |= CAPTIOPOSEL1; break;
case 3: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL1; break;
case 4: CAPTIOCTL |= CAPTIOPOSEL2; break;
case 5: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL2; break;
case 6: CAPTIOCTL |= CAPTIOPOSEL1 + CAPTIOPOSEL2; break;
case 7: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL1 + CAPTIOPOSEL2; break;
case 8: CAPTIOCTL |= CAPTIOPOSEL3; break;
case 9: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL3; break;
case 10: CAPTIOCTL |= CAPTIOPOSEL1 + CAPTIOPOSEL3; break;
case 11: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL1 + CAPTIOPOSEL3; break;
case 12: CAPTIOCTL |= CAPTIOPOSEL2 + CAPTIOPOSEL3; break;
case 13: CAPTIOCTL |= CAPTIOPOSEL0 + CAPTIOPOSEL2 + CAPTIOPOSEL3; break;
case 14: CAPTIOCTL |= CAPTIOPOSEL1 + CAPTIOPOSEL2 + CAPTIOPOSEL3; break;
case 15: CAPTIOCTL |= CAPTIOPOSEL0 +CAPTIOPOSEL1 + CAPTIOPOSEL2 + CAPTIOPOSEL3; break;
default: break;
}
switch(PIN)
{
case BIT0: break;
case BIT1: CAPTIOCTL |= CAPTIOPISEL0; break;
case BIT2: CAPTIOCTL |= CAPTIOPISEL1; break;
case BIT3: CAPTIOCTL |= CAPTIOPISEL0 + CAPTIOPISEL1; break;
case BIT4: CAPTIOCTL |= CAPTIOPISEL2; break;
case BIT5: CAPTIOCTL |= CAPTIOPISEL0 + CAPTIOPISEL2; break;
case BIT6: CAPTIOCTL |= CAPTIOPISEL1 + CAPTIOPISEL2; break;
case BIT7: CAPTIOCTL |= CAPTIOPISEL0 + CAPTIOPISEL1 + CAPTIOPISEL2; break;
default: break;
}
CAPTIOCTL |= CAPTIOEN;
}
void pulse_LED(void)
{
switch (key_pressed)
{
case 0: P1OUT &= ~(LED_1 + LED_2); break;
case 1: P1OUT |= LED_1; break;
case 2: P1OUT |= LED_2; break;
case 3: P1OUT |= LED_1 + LED_2; break;
case 4: P1OUT ^= LED_1 + LED_2; break;
}
}
/* 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
}
Regards,
Ling
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