timer.c
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/*
* Copyright (C) 2014 Freie Universität Berlin
*
* 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_lpc1768
* @{
*
* @file
* @brief Implementation of the low-level timer driver for the LPC1768
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @}
*/
#include <stdint.h>
#include "cpu.h"
#include "periph_conf.h"
#include "periph/timer.h"
/* guard file in case no timers are defined */
#if TIMER_0_EN
/**
* @name Timer channel interrupt flags
* @{
*/
#define MR0_FLAG (0x01) /**< match for channel 0 */
#define MR1_FLAG (0x02) /**< match for channel 1 */
#define MR2_FLAG (0x04) /**< match for channel 2 */
#define MR3_FLAG (0x08) /**< match for channel 3 */
/** @} */
/**
* @brief UART device configurations
*/
static timer_isr_ctx_t config[TIMER_NUMOF];
int timer_init(tim_t dev, unsigned long freq, timer_cb_t cb, void *arg)
{
if (dev == TIMER_0) {
/* save callback */
config[TIMER_0].cb = cb;
config[TIMER_0].arg = arg;
/* enable power for timer */
TIMER_0_CLKEN();
/* let timer run with full frequency */
TIMER_0_PLKSEL();
/* set to timer mode */
TIMER_0_DEV->CTCR = 0;
/* configure prescaler */
TIMER_0_DEV->PR = (TIMER_0_FREQ / freq) - 1;
/* configure and enable timer interrupts */
NVIC_SetPriority(TIMER_0_IRQ, TIMER_IRQ_PRIO);
NVIC_EnableIRQ(TIMER_0_IRQ);
/* enable timer */
TIMER_0_DEV->TCR |= 1;
return 0;
}
return -1;
}
int timer_set(tim_t dev, int channel, unsigned int timeout)
{
if (dev == TIMER_0) {
unsigned int now = timer_read(dev);
return timer_set_absolute(dev, channel, now + timeout);
}
return -1;
}
int timer_set_absolute(tim_t dev, int channel, unsigned int value)
{
if (dev == TIMER_0) {
switch (channel) {
case 0:
TIMER_0_DEV->MR0 = value;
break;
case 1:
TIMER_0_DEV->MR1 = value;
break;
case 2:
TIMER_0_DEV->MR2 = value;
break;
case 3:
TIMER_0_DEV->MR3 = value;
break;
default:
return -1;
}
TIMER_0_DEV->MCR |= (1 << (channel * 3));
return 1;
}
return -1;
}
int timer_clear(tim_t dev, int channel)
{
if (dev == TIMER_0 && channel >= 0 && channel < TIMER_0_CHANNELS) {
TIMER_0_DEV->MCR &= ~(1 << (channel * 3));
return 1;
}
return -1;
}
unsigned int timer_read(tim_t dev)
{
if (dev == TIMER_0) {
return (unsigned int)TIMER_0_DEV->TC;
}
return 0;
}
void timer_start(tim_t dev)
{
if (dev == TIMER_0) {
TIMER_0_DEV->TCR |= 1;
}
}
void timer_stop(tim_t dev)
{
if (dev == TIMER_0) {
TIMER_0_DEV->TCR &= ~(1);
}
}
void timer_irq_enable(tim_t dev)
{
if (dev == TIMER_0) {
NVIC_EnableIRQ(TIMER_0_IRQ);
}
}
void timer_irq_disable(tim_t dev)
{
if (dev == TIMER_0) {
NVIC_DisableIRQ(TIMER_0_IRQ);
}
}
#if TIMER_0_EN
void TIMER_0_ISR(void)
{
if (TIMER_0_DEV->IR & MR0_FLAG) {
TIMER_0_DEV->IR |= (MR0_FLAG);
TIMER_0_DEV->MCR &= ~(1 << 0);
config[TIMER_0].cb(config[TIMER_0].arg, 0);
}
if (TIMER_0_DEV->IR & MR1_FLAG) {
TIMER_0_DEV->IR |= (MR1_FLAG);
TIMER_0_DEV->MCR &= ~(1 << 3);
config[TIMER_0].cb(config[TIMER_0].arg, 1);
}
if (TIMER_0_DEV->IR & MR2_FLAG) {
TIMER_0_DEV->IR |= (MR2_FLAG);
TIMER_0_DEV->MCR &= ~(1 << 6);
config[TIMER_0].cb(config[TIMER_0].arg, 2);
}
if (TIMER_0_DEV->IR & MR3_FLAG) {
TIMER_0_DEV->IR |= (MR3_FLAG);
TIMER_0_DEV->MCR &= ~(1 << 9);
config[TIMER_0].cb(config[TIMER_0].arg, 3);
}
cortexm_isr_end();
}
#endif
#endif /* TIMER_0_EN */