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Diffstat (limited to 'lib/msp430/Tone.cpp')
| -rwxr-xr-x | lib/msp430/Tone.cpp | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/lib/msp430/Tone.cpp b/lib/msp430/Tone.cpp new file mode 100755 index 0000000..dd4aaeb --- /dev/null +++ b/lib/msp430/Tone.cpp @@ -0,0 +1,223 @@ +/* Tone.cpp + + A Tone Generator Library - Modified for Energia + Implements up to 3 (software) PWM outputs using TIMERA0 compare registers and IRQ. + Can use any digital output pin for pulse generation + + (c) 2012 - Peter Brier. + + Based on code Originally written by Brett Hagman + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + +Version Modified By Date Comments +------- ----------- -------- -------- +0001 B Hagman 09/08/02 Initial coding +0002 B Hagman 09/08/18 Multiple pins +0003 B Hagman 09/08/18 Moved initialization from constructor to begin() +0004 B Hagman 09/09/26 Fixed problems with ATmega8 +0005 B Hagman 09/11/23 Scanned prescalars for best fit on 8 bit timers + 09/11/25 Changed pin toggle method to XOR + 09/11/25 Fixed timer0 from being excluded +0006 D Mellis 09/12/29 Replaced objects with functions +0007 M Sproul 10/08/29 Changed #ifdefs from cpu to register +0008 P Brier 12/05/28 Modified for TI MSP430 processor +0009 P Brier 12/05/29 Fixed problem with re-init of expired tone +*************************************************/ + +#include "wiring_private.h" +#include "pins_energia.h" +#include "Energia.h" + +// local funcions +static void initTimers(); +static void setTimer(uint8_t n, unsigned int frequency, unsigned long duration); +static void stopTimer(uint8_t n); + +// timer clock frequency set to clock/8, at F_CPU = 1MHZ this gives an output freq range of ~[1Hz ..65Khz] and at 16Mhz this is ~[16Hz .. 1MHz] +#define F_TIMER (F_CPU/8L) + +#ifdef __MSP430_HAS_TA3__ +#define AVAILABLE_TONE_PINS 3 +#define SETARRAY(a) a,a,a +#else +#define AVAILABLE_TONE_PINS 2 +#define SETARRAY(a) a,a +#endif + + +// tone_duration: +// > 0 - duration specified +// = 0 - stopped +// < 0 - infinitely (until stop() method called, or new play() called) + +static uint8_t tone_state = 0; // 0==not initialized, 1==timer running +static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { SETARRAY(255) }; +static uint8_t tone_bit[AVAILABLE_TONE_PINS] = { SETARRAY(255) }; +volatile static uint8_t *tone_out[AVAILABLE_TONE_PINS] = { SETARRAY(0) }; +static uint16_t tone_interval[AVAILABLE_TONE_PINS] = { SETARRAY(-1) }; +static int16_t tone_periods[AVAILABLE_TONE_PINS] = { SETARRAY(0) }; + + +/** +*** tone() -- Output a tone (50% Dutycycle PWM signal) on a pin +*** pin: This pin is selected as output +*** frequency: [Hertz] +** duration: [milliseconds], if duration <=0, then we output tone continously, otherwise tone is stopped after this time (output = 0) +**/ +void tone(uint8_t _pin, unsigned int frequency, unsigned long duration) +{ + uint8_t port = digitalPinToPort(_pin); + if (port == NOT_A_PORT) return; + + // find if we are using it at the moment, if so: update it + for (int i = 0; i < AVAILABLE_TONE_PINS; i++) + { + if (tone_pins[i] == _pin) + { + setTimer(i, frequency, duration); + return; // we are done, timer reprogrammed + } + } + + // new tone pin, find empty timer and set it + for (int i = 0; i < AVAILABLE_TONE_PINS; i++) + { + if (tone_pins[i] == 255) + { + tone_pins[i] = _pin; + tone_bit[i] = digitalPinToBitMask(_pin); + tone_out[i] = portOutputRegister(port); + if ( tone_state == 0 ) + initTimers(); + pinMode(_pin, OUTPUT); + setTimer(i, frequency, duration); + return; // we are done, timer set + } + } + // if we exit here, no unused timer was found, nothing is done +} + + +/** +*** noTone() - Stop outputting the tone on a pin +**/ +void noTone(uint8_t _pin) +{ + if ( _pin == 255 ) return; // Should not happen! + for (int i = 0; i < AVAILABLE_TONE_PINS; i++) + { + if (tone_pins[i] == _pin) + { + tone_pins[i] = 255; + stopTimer(i); + } + } +} + + +// Initialize the timers - Set mode and Enable IRQ +static void inline initTimers() +{ + // disable IRQs + TA0CCTL0 = 0; + TA0CCTL1 = 0; +#ifdef __MSP430_HAS_TA3__ + TA0CCTL2 = 0; +#endif + TA0CTL = TACLR + TASSEL_2 + ID_3 + MC_2; // clear counter, source=SMCLK/8, mode=continous count up + tone_state = 1; // init is done +} + + +// Set the timer interval and duration +// frequency in [Hz] and duration in [msec] +// we initialize the timer match value only if the tone was not running already, to prevent glitches when re-programming a running tone +static void setTimer(uint8_t n, unsigned int frequency, unsigned long duration) +{ + if ( frequency <= 0 ) + { + tone_interval[n] = 0; + tone_periods[n] = 0; + return; + } + tone_interval[n] = F_TIMER / (2L*frequency); + if ( duration > 0 ) + tone_periods[n] = (duration * (F_TIMER/2)) / (1000L * tone_interval[n]); + else + tone_periods[n] = -1; + switch( n ) // enable IRQ and set next match time in various timer compare registers (if we where not enabled already) + { + case 0: + if ( ! (TA0CCTL0 & CCIE) ) TA0CCR0 = TA0R + tone_interval[0]; + TA0CCTL0 = CCIE; + break; + case 1: + if ( !(TA0CCTL1 & CCIE) ) TA0CCR1 = TA0R + tone_interval[1]; + TA0CCTL1 = CCIE; + break; +#ifdef __MSP430_HAS_TA3__ + case 2: + if ( !(TA0CCTL2 & CCIE) ) TA0CCR2 = TA0R + tone_interval[2]; + TA0CCTL2 = CCIE; + break; +#endif + } +} + +/* stopTimer() - Disable timer IRQ */ +static void inline stopTimer(uint8_t n) +{ + switch( n ) + { + case 0: TA0CCTL0 = 0; break; + case 1: TA0CCTL1 = 0; break; +#ifdef __MSP430_HAS_TA3__ + case 2: TA0CCTL2 = 0; break; +#endif + } + *tone_out[n] &= ~tone_bit[n]; +} + + +// Peform the isr magic, toggle output, decrease duation if > 0, and stop if duration == 0, continous if duration < 0 +// set new interval - defined as macro to limit ISR overhead (at the expense of some code size) +#define isrTimer(n,ccr) do { \ + *tone_out[n] ^= tone_bit[n]; \ + if ( tone_periods[n] == 0 ) stopTimer(n);\ + else if ( tone_periods[n] > 0) tone_periods[n]--; \ + ccr += tone_interval[n]; \ +} while(0) + + +// TIMERA vector (CCR0) +__attribute__((interrupt(TIMER0_A0_VECTOR))) +void TIMER0_A0_ISR(void) +{ + isrTimer(0, TA0CCR0); +} + +// TAIV vector (CCR1/CCR2) +__attribute__((interrupt(TIMER0_A1_VECTOR))) +void TIMER0_A1_ISR(void) +{ + switch ( TA0IV ) + { + case 0x2: isrTimer(1, TA0CCR1); break; // CCR1 +#ifdef __MSP430_HAS_TA3__ + case 0x4: isrTimer(2, TA0CCR2); break; // CCR2 +#endif + } +} |