btstack/platforms/msp-exp430f5438-cc2564b/hal_tick.c
2014-11-06 23:11:45 +00:00

87 lines
2.8 KiB
C

/*
* Copyright (C) 2011 by Matthias Ringwald
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD 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 MATTHIAS
* RINGWALD 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.
*
*/
/*
* hal_tick.c
*
* Implementation for MSP430 Experimenter board using 250 ms ticks provided by Timer A1
*
*/
#include <msp430x54x.h>
#include <stdlib.h>
#include "hal_compat.h"
#include <btstack/hal_tick.h>
static void dummy_handler(void){};
static void (*tick_handler)(void) = &dummy_handler;
// Auxillary Clock (ACLK) = 32768 hz
// 8192 ticks = 1/4 second
#define TIMER_COUNTDOWN 8192
void hal_tick_init(void){
TA1CCTL0 = CCIE; // CCR0 interrupt enabled
TA1CTL = TASSEL_1 | MC_2 | TACLR; // use ACLK (32768), contmode, clear TAR
TA1CCR0 = TIMER_COUNTDOWN; // -> 1/4 s
}
void hal_tick_set_handler(void (*handler)(void)){
if (handler == NULL){
tick_handler = &dummy_handler;
return;
}
tick_handler = handler;
}
int hal_tick_get_tick_period_in_ms(void){
return 250;
}
// Timer A1 interrupt service routine
#ifdef __GNUC__
__attribute__((interrupt(TIMER1_A0_VECTOR)))
#endif
#ifdef __IAR_SYSTEMS_ICC__
#pragma vector=TIMER1_A0_VECTOR
__interrupt
#endif
void timerA0ISR(void){
TA1CCR0 += TIMER_COUNTDOWN;
(*tick_handler)();
// force exit low power mode
__bic_SR_register_on_exit(LPM0_bits); // Exit active CPU
}