1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 39 /* 40 * hal_tick.c 41 * 42 * Implementation for MSP430 Experimenter board using 250 ms ticks provided by Timer A1 43 * 44 */ 45 46 #include <msp430x54x.h> 47 #include <stdlib.h> 48 #include "hal_compat.h" 49 50 #include "hal_tick.h" 51 52 static void dummy_handler(void){}; 53 54 static void (*tick_handler)(void) = &dummy_handler; 55 56 // Auxillary Clock (ACLK) = 32768 hz 57 // 8192 ticks = 1/4 second 58 59 #define TIMER_COUNTDOWN 8192 60 61 void hal_tick_init(void){ 62 TA1CCTL0 = CCIE; // CCR0 interrupt enabled 63 TA1CTL = TASSEL_1 | MC_2 | TACLR; // use ACLK (32768), contmode, clear TAR 64 TA1CCR0 = TIMER_COUNTDOWN; // -> 1/4 s 65 } 66 67 void hal_tick_set_handler(void (*handler)(void)){ 68 if (handler == NULL){ 69 tick_handler = &dummy_handler; 70 return; 71 } 72 tick_handler = handler; 73 } 74 75 int hal_tick_get_tick_period_in_ms(void){ 76 return 250; 77 } 78 79 // Timer A1 interrupt service routine 80 #ifdef __GNUC__ 81 __attribute__((interrupt(TIMER1_A0_VECTOR))) 82 #endif 83 #ifdef __IAR_SYSTEMS_ICC__ 84 #pragma vector=TIMER1_A0_VECTOR 85 __interrupt 86 #endif 87 void timerA0ISR(void){ 88 TA1CCR0 += TIMER_COUNTDOWN; 89 (*tick_handler)(); 90 91 // force exit low power mode 92 __bic_SR_register_on_exit(LPM0_bits); // Exit active CPU 93 } 94