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/**
* Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "sdk_common.h"
#if NRF_MODULE_ENABLED(SYSTICK)
#include "nrf_drv_systick.h"
#include "nrf_systick.h"
#include "nrf.h"
#include "nrf_assert.h"
/**
* @brief Maximum number of ticks to delay
*
* The maximum number of ticks should be much lower than
* Physical maximum count of the SysTick timer.
* It is dictated by the fact that it would be impossible to detect delay
* properly when the timer value warps around the starting point.
*/
#define NRF_DRV_SYSTICK_TICKS_MAX (NRF_SYSTICK_VAL_MASK / 2UL)
/**
* @brief Number of milliseconds in a second
*/
#define NRF_DRV_SYSTICK_MS (1000UL)
/**
* @brief Number of microseconds in a second
*/
#define NRF_DRV_SYSTICK_US (1000UL * NRF_DRV_SYSTICK_MS)
/**
* @brief Number of milliseconds to wait in single loop
*
* Constant used by @ref nrd_drv_systick_delay_ms function
* to split waiting into loops and rest.
*
* It describes the number of milliseconds to wait in single loop.
*
* See @ref nrf_drv_systick_delay_ms source code for details.
*/
#define NRF_DRV_SYSTICK_MS_STEP (64U)
/**
* @brief Checks if the given time is in correct range
*
* Function tests given time is not to big for this library.
* Assertion is used for testing.
*
* @param us Time in microseconds to check
*/
#define NRF_DRV_SYSTICK_ASSERT_TIMEOUT(us) \
ASSERT(us <= (NRF_DRV_SYSTICK_TICKS_MAX / ((SystemCoreClock) / NRF_DRV_SYSTICK_US)));
/**
* @brief Function that converts microseconds to ticks
*
* Function converts from microseconds to CPU ticks.
*
* @param us Number of microseconds
*
* @return Number of ticks
*
* @sa nrf_drv_systick_ms_tick
*/
static inline uint32_t nrf_drv_systick_us_tick(uint32_t us)
{
return us * ((SystemCoreClock) / NRF_DRV_SYSTICK_US);
}
/**
* @brief Function that converts milliseconds to ticks
*
* Function converts from milliseconds to CPU ticks.
*
* @param us Number of milliseconds
*
* @return Number of ticks
*
* @sa nrf_drv_systick_us_tick
*/
static inline uint32_t nrf_drv_systick_ms_tick(uint32_t ms)
{
return ms * ((SystemCoreClock) / NRF_DRV_SYSTICK_MS);
}
void nrf_drv_systick_init(void)
{
nrf_systick_load_set(NRF_SYSTICK_VAL_MASK);
nrf_systick_csr_set(
NRF_SYSTICK_CSR_CLKSOURCE_CPU |
NRF_SYSTICK_CSR_TICKINT_DISABLE |
NRF_SYSTICK_CSR_ENABLE);
}
void nrf_drv_systick_get(nrf_drv_systick_state_t * p_state)
{
p_state->time = nrf_systick_val_get();
}
bool nrf_drv_systick_test(nrf_drv_systick_state_t const * p_state, uint32_t us)
{
NRF_DRV_SYSTICK_ASSERT_TIMEOUT(us);
const uint32_t diff = NRF_SYSTICK_VAL_MASK & ((p_state->time) - nrf_systick_val_get());
return (diff >= nrf_drv_systick_us_tick(us));
}
void nrf_drv_systick_delay_ticks(uint32_t ticks)
{
ASSERT(ticks <= NRF_DRV_SYSTICK_TICKS_MAX)
const uint32_t start = nrf_systick_val_get();
while((NRF_SYSTICK_VAL_MASK & (start - nrf_systick_val_get())) < ticks)
{
/* Nothing to do */
}
}
void nrf_drv_systick_delay_us(uint32_t us)
{
NRF_DRV_SYSTICK_ASSERT_TIMEOUT(us);
nrf_drv_systick_delay_ticks(nrf_drv_systick_us_tick(us));
}
void nrf_drv_systick_delay_ms(uint32_t ms)
{
uint32_t n = ms / NRF_DRV_SYSTICK_MS_STEP;
uint32_t r = ms % NRF_DRV_SYSTICK_MS_STEP;
while(0 != (n--))
{
nrf_drv_systick_delay_ticks(nrf_drv_systick_ms_tick(NRF_DRV_SYSTICK_MS_STEP));
}
nrf_drv_systick_delay_ticks(nrf_drv_systick_ms_tick(r));
}
#endif // NRF_MODULE_ENABLED(SYSTICK)
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