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RIOT/cpu/stm32/periph/timer.c
2020-06-24 12:58:38 +02:00

156 lines
3.1 KiB
C

/*
* Copyright (C) 2014-2016 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_stm32
* @ingroup drivers_periph_timer
* @{
*
* @file
* @brief Low-level timer driver implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
*
* @}
*/
#include "cpu.h"
#include "periph/timer.h"
/**
* @brief Interrupt context for each configured timer
*/
static timer_isr_ctx_t isr_ctx[TIMER_NUMOF];
/**
* @brief Get the timer device
*/
static inline TIM_TypeDef *dev(tim_t tim)
{
return timer_config[tim].dev;
}
int timer_init(tim_t tim, unsigned long freq, timer_cb_t cb, void *arg)
{
/* check if device is valid */
if (tim >= TIMER_NUMOF) {
return -1;
}
/* remember the interrupt context */
isr_ctx[tim].cb = cb;
isr_ctx[tim].arg = arg;
/* enable the peripheral clock */
periph_clk_en(timer_config[tim].bus, timer_config[tim].rcc_mask);
/* configure the timer as upcounter in continuous mode */
dev(tim)->CR1 = 0;
dev(tim)->CR2 = 0;
dev(tim)->ARR = timer_config[tim].max;
/* set prescaler */
dev(tim)->PSC = ((periph_timer_clk(timer_config[tim].bus) / freq) - 1);
/* generate an update event to apply our configuration */
dev(tim)->EGR = TIM_EGR_UG;
/* enable the timer's interrupt */
NVIC_EnableIRQ(timer_config[tim].irqn);
/* reset the counter and start the timer */
timer_start(tim);
return 0;
}
int timer_set_absolute(tim_t tim, int channel, unsigned int value)
{
if (channel >= (int)TIMER_CHANNEL_NUMOF) {
return -1;
}
TIM_CHAN(tim, channel) = (value & timer_config[tim].max);
dev(tim)->SR &= ~(TIM_SR_CC1IF << channel);
dev(tim)->DIER |= (TIM_DIER_CC1IE << channel);
return 0;
}
int timer_clear(tim_t tim, int channel)
{
if (channel >= (int)TIMER_CHANNEL_NUMOF) {
return -1;
}
dev(tim)->DIER &= ~(TIM_DIER_CC1IE << channel);
return 0;
}
unsigned int timer_read(tim_t tim)
{
return (unsigned int)dev(tim)->CNT;
}
void timer_start(tim_t tim)
{
dev(tim)->CR1 |= TIM_CR1_CEN;
}
void timer_stop(tim_t tim)
{
dev(tim)->CR1 &= ~(TIM_CR1_CEN);
}
static inline void irq_handler(tim_t tim)
{
uint32_t status = (dev(tim)->SR & dev(tim)->DIER);
for (unsigned int i = 0; i < TIMER_CHANNEL_NUMOF; i++) {
if (status & (TIM_SR_CC1IF << i)) {
dev(tim)->DIER &= ~(TIM_DIER_CC1IE << i);
isr_ctx[tim].cb(isr_ctx[tim].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
#ifdef TIMER_3_ISR
void TIMER_3_ISR(void)
{
irq_handler(3);
}
#endif
#ifdef TIMER_4_ISR
void TIMER_4_ISR(void)
{
irq_handler(4);
}
#endif