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RIOT/cpu/saml21/periph/rtt.c

148 lines
3.3 KiB
C

/*
* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
* 2015 FreshTemp, LLC.
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_saml21
* @ingroup drivers_periph_rtt
* @{
*
* @file rtt.c
* @brief Low-level RTT driver implementation
*
* @author Kaspar Schleiser <kaspar@schleiser.de>
*
* @}
*/
#include <stdint.h>
#include "periph/rtt.h"
#include "board.h"
#define ENABLE_DEBUG 0
#include "debug.h"
static rtt_cb_t _overflow_cb;
static void* _overflow_arg;
static rtt_cb_t _cmp0_cb;
static void* _cmp0_arg;
void rtt_init(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
rtt_poweron();
/* reset */
RTC->MODE0.CTRLA.bit.SWRST = 1;
while(RTC->MODE0.CTRLA.bit.SWRST) {}
/* set 32bit counting mode */
RTC->MODE0.CTRLA.bit.MODE = 0;
/* set clock source */
OSC32KCTRL->RTCCTRL.reg = OSC32KCTRL_RTCCTRL_RTCSEL_ULP32K;
/* enable */
RTC->MODE0.CTRLA.bit.ENABLE = 1;
while(RTC->MODE0.SYNCBUSY.bit.ENABLE) {}
/* initially clear flag */
RTC->MODE0.INTFLAG.reg |= RTC_MODE1_INTFLAG_CMP(1 << 0);
/* enable RTT IRQ */
NVIC_EnableIRQ(RTC_IRQn);
DEBUG("%s:%d %u\n", __func__, __LINE__, (unsigned)rtt_get_counter());
}
void rtt_set_overflow_cb(rtt_cb_t cb, void *arg)
{
DEBUG("%s:%d\n", __func__, __LINE__);
/* clear overflow cb to avoid race while assigning */
rtt_clear_overflow_cb();
/* set callback variables */
_overflow_cb = cb;
_overflow_arg = arg;
/* enable overflow interrupt */
RTC->MODE0.INTENSET.bit.OVF = 1;
}
void rtt_clear_overflow_cb(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
/* disable overflow interrupt */
RTC->MODE0.INTENCLR.bit.OVF = 1;
}
uint32_t rtt_get_counter(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
while (RTC->MODE0.SYNCBUSY.bit.COUNT) {}
return RTC->MODE0.COUNT.reg;
}
void rtt_set_alarm(uint32_t alarm, rtt_cb_t cb, void *arg)
{
DEBUG("%s:%d alarm=%u\n", __func__, __LINE__, (unsigned)alarm);
/* disable interrupt to avoid race */
rtt_clear_alarm();
/* set COM register */
while (RTC->MODE0.SYNCBUSY.bit.COMP0) {}
RTC->MODE0.COMP[0].reg = alarm;
/* setup callback */
_cmp0_cb = cb;
_cmp0_arg = arg;
/* enable compare interrupt */
RTC->MODE0.INTENSET.bit.CMP0 = 1;
}
void rtt_clear_alarm(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
/* clear compare interrupt */
RTC->MODE0.INTENCLR.bit.CMP0 = 1;
}
void rtt_poweron(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
MCLK->APBAMASK.reg |= MCLK_APBAMASK_RTC;
}
void rtt_poweroff(void)
{
DEBUG("%s:%d\n", __func__, __LINE__);
MCLK->APBAMASK.reg &= ~MCLK_APBAMASK_RTC;
}
void isr_rtc(void)
{
if (RTC->MODE0.INTFLAG.bit.OVF) {
RTC->MODE0.INTFLAG.reg |= RTC_MODE0_INTFLAG_OVF;
if (_overflow_cb) {
_overflow_cb(_overflow_arg);
}
}
if (RTC->MODE0.INTFLAG.bit.CMP0) {
/* clear flag */
RTC->MODE0.INTFLAG.reg |= RTC_MODE1_INTFLAG_CMP(1 << 0);
/* disable interrupt */
RTC->MODE0.INTENCLR.bit.CMP0 = 1;
if (_cmp0_cb) {
_cmp0_cb(_cmp0_arg);
}
}
cortexm_isr_end();
}