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/*
* Copyright (C) 2014-2016 Freie Universität Berlin
* 2015 Jan Wagner <mail@jwagner.eu>
*
* 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_nrf5x_common
* @{
*
* @file
* @brief Implementation of the peripheral timer interface
*
* @author Christian Kühling <kuehling@zedat.fu-berlin.de>
* @author Timo Ziegler <timo.ziegler@fu-berlin.de>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Jan Wagner <mail@jwagner.eu>
*
* @}
*/
#include "periph/timer.h"
#define F_TIMER (16000000U) /* the timer is clocked at 16MHz */
typedef struct {
timer_cb_t cb;
void *arg;
uint8_t flags;
} tim_ctx_t;
/**
* @brief timer state memory
*/
static tim_ctx_t ctx[TIMER_NUMOF];
static inline NRF_TIMER_Type *dev(tim_t tim)
{
return timer_config[tim].dev;
}
int timer_init(tim_t tim, unsigned long freq, timer_cb_t cb, void *arg)
{
/* make sure the given timer is valid */
if (tim >= TIMER_NUMOF) {
return -1;
}
/* save interrupt context */
ctx[tim].cb = cb;
ctx[tim].arg = arg;
/* power on timer */
#if CPU_FAM_NRF51
dev(tim)->POWER = 1;
#endif
/* reset and configure the timer */
dev(tim)->TASKS_STOP = 1;
dev(tim)->BITMODE = timer_config[tim].bitmode;
dev(tim)->MODE = TIMER_MODE_MODE_Timer;
dev(tim)->TASKS_CLEAR = 1;
/* figure out if desired frequency is available */
int i;
unsigned long cando = F_TIMER;
for (i = 0; i < 10; i++) {
if (freq == cando) {
dev(tim)->PRESCALER = i;
break;
}
cando /= 2;
}
if (i == 10) {
return -1;
}
/* reset compare state */
dev(tim)->EVENTS_COMPARE[0] = 0;
dev(tim)->EVENTS_COMPARE[1] = 0;
dev(tim)->EVENTS_COMPARE[2] = 0;
/* enable interrupts */
timer_irq_enable(tim);
/* start the timer */
dev(tim)->TASKS_START = 1;
return 0;
}
int timer_set(tim_t tim, int chan, unsigned int value)
{
uint32_t now = timer_read(tim);
return timer_set_absolute(tim, chan, (now + value));
}
int timer_set_absolute(tim_t tim, int chan, unsigned int value)
{
/* see if channel is valid */
if (chan >= timer_config[tim].channels) {
return -1;
}
ctx[tim].flags |= (1 << chan);
dev(tim)->CC[chan] = value;
dev(tim)->INTENSET = (TIMER_INTENSET_COMPARE0_Msk << chan);
return 1;
}
int timer_clear(tim_t tim, int chan)
{
/* see if channel is valid */
if (chan >= timer_config[tim].channels) {
return -1;
}
dev(tim)->INTENCLR = (TIMER_INTENSET_COMPARE0_Msk << chan);
ctx[tim].flags &= ~(1 << chan);
return 1;
}
unsigned int timer_read(tim_t tim)
{
dev(tim)->TASKS_CAPTURE[timer_config[tim].channels] = 1;
return dev(tim)->CC[timer_config[tim].channels];
}
void timer_start(tim_t tim)
{
dev(tim)->TASKS_START = 1;
}
void timer_stop(tim_t tim)
{
dev(tim)->TASKS_STOP = 1;
}
void timer_irq_enable(tim_t tim)
{
NVIC_EnableIRQ(timer_config[tim].irqn);
}
void timer_irq_disable(tim_t tim)
{
NVIC_DisableIRQ(timer_config[tim].irqn);
}
static inline void irq_handler(int num)
{
for (unsigned i = 0; i < timer_config[num].channels; i++) {
if (dev(num)->EVENTS_COMPARE[i] == 1) {
dev(num)->EVENTS_COMPARE[i] = 0;
if (ctx[num].flags & (1 << i)) {
ctx[num].flags &= ~(1 << i);
dev(num)->INTENCLR = (TIMER_INTENSET_COMPARE0_Msk << i);
ctx[num].cb(ctx[num].arg, i);
}
}
}
cortexm_isr_end();
}
#ifdef TIMER_0_ISR
void TIMER_0_ISR(void)
{
irq_handler(0);
}
#endif
#ifdef TIMER_1_ISR
void TIMER_1_ISR(void)
{
irq_handler(1);
}
#endif
#ifdef TIMER_2_ISR
void TIMER_2_ISR(void)
{
irq_handler(2);
}
#endif
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