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https://github.com/RIOT-OS/RIOT.git
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129 lines
2.7 KiB
C
129 lines
2.7 KiB
C
/*
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* Copyright (C) 2015 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_cc430
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* @ingroup drivers_periph_timer
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* @{
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*
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* @file
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* @brief Low-level timer driver implementation
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*
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* This implementation does only support one fixed timer, as defined in the
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* boards periph_conf.h file.
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*
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* @todo Generalize to handle more timers and make them configurable
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* through the board's `periph_conf.h`
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include "cpu.h"
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#include "periph_cpu.h"
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#include "periph_conf.h"
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#include "periph/timer.h"
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/**
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* @brief Save reference to the timer callback
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*/
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static timer_cb_t isr_cb;
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/**
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* @brief Save argument for the callback
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*/
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static void *isr_arg;
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int timer_init(tim_t dev, unsigned long freq, timer_cb_t cb, void *arg)
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{
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/* using fixed TIMER_BASE for now */
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if (dev != 0) {
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return -1;
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}
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/* TODO: configure time-base depending on freq value */
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if (freq != 1000000ul) {
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return -1;
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}
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/* reset the timer A configuration */
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TIMER_BASE->CTL = CTL_CLR;
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/* save callback */
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isr_cb = cb;
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isr_arg = arg;
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/* configure timer to use the SMCLK with prescaler of 8 */
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TIMER_BASE->CTL = (CTL_TASSEL_SMCLK | CTL_ID_DIV8);
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/* configure CC channels */
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for (int i = 0; i < TIMER_CHAN; i++) {
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TIMER_BASE->CCTL[i] = 0;
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}
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/* start the timer in continuous mode */
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TIMER_BASE->CTL |= CTL_MC_CONT;
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return 0;
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}
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int timer_set_absolute(tim_t dev, int channel, unsigned int value)
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{
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if (dev != 0 || channel >= TIMER_CHAN) {
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return -1;
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}
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TIMER_BASE->CCR[channel] = value;
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TIMER_BASE->CCTL[channel] &= ~(CCTL_CCIFG);
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TIMER_BASE->CCTL[channel] |= (CCTL_CCIE);
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return 0;
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}
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int timer_clear(tim_t dev, int channel)
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{
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if (dev != 0 || channel >= TIMER_CHAN) {
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return -1;
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}
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TIMER_BASE->CCTL[channel] &= ~(CCTL_CCIE);
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return 0;
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}
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unsigned int timer_read(tim_t dev)
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{
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(void)dev;
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return (unsigned int)TIMER_BASE->R;
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}
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void timer_start(tim_t dev)
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{
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(void)dev;
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TIMER_BASE->CTL |= CTL_MC_CONT;
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}
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void timer_stop(tim_t dev)
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{
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(void)dev;
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TIMER_BASE->CTL &= ~(CTL_MC_MASK);
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}
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ISR(TIMER_ISR_CC0, isr_timer_a_cc0)
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{
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__enter_isr();
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TIMER_BASE->CCTL[0] &= ~(CCTL_CCIE);
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isr_cb(isr_arg, 0);
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__exit_isr();
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}
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ISR(TIMER_ISR_CCX, isr_timer_a_ccx_isr)
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{
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__enter_isr();
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int chan = (int)(TIMER_BASE->IV >> 1);
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TIMER_BASE->CCTL[chan] &= ~(CCTL_CCIE);
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isr_cb(isr_arg, chan);
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__exit_isr();
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}
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