xref: /btstack/port/archive/msp-exp430f5438-cc2564b/src/hal_tick.c (revision 2fca4dad957cd7b88f4657ed51e89c12615dda72)

/*
 * Copyright (C) 2014 BlueKitchen GmbH
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/*
 *  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 "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
}