rtc, keeping time

2 files changed, 305 insertions, 0 deletions

diff --git a/drivers_nrf/systick/nrf_drv_systick.c b/drivers_nrf/systick/nrf_drv_systick.c
new file mode 100644
index 0000000..242ee64
--- /dev/null
+++ b/drivers_nrf/systick/nrf_drv_systick.c
@@ -0,0 +1,172 @@
+/**
+ * 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)
diff --git a/drivers_nrf/systick/nrf_drv_systick.h b/drivers_nrf/systick/nrf_drv_systick.h
new file mode 100644
index 0000000..34492af
--- /dev/null
+++ b/drivers_nrf/systick/nrf_drv_systick.h
@@ -0,0 +1,133 @@
+/**
+ * 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.
+ * 
+ */
+#ifndef NRF_DRV_SYSTICK_H__
+#define NRF_DRV_SYSTICK_H__
+#include <stdint.h>
+#include <stdbool.h>
+
+
+/**
+ * @addtogroup nrf_systick SysTick HAL and driver
+ * @ingroup nrf_drivers
+ * @brief System Timer (SysTick) APIs
+ *
+ * The SysTick HAL provides basic APIs for accessing the registers of the system timer (SysTick).
+ * The SysTick driver provides APIs on a higher level.
+ */
+
+/**
+ * @defgroup nrf_drv_systick SysTick driver
+ * @{
+ * @ingroup nrf_systick
+ *
+ * This library configures SysTick as a free-running timer.
+ * This timer is used to generate delays and pool for timeouts.
+ * Only relatively short timeouts are supported.
+ * The SysTick works on 64MHz and is 24-bits wide.
+ * It means that it overflows around 4 times per second and around 250&nbsp;ms
+ * would be the highest supported time in the library.
+ * But it would be really hard to detect if overflow was generated without
+ * using interrupts. For safely we would limit the maximum delay range by half.
+ */
+
+/**
+ * @brief The value type that holds the SysTick state
+ *
+ * This variable is used to count the requested timeout.
+ * @sa nrf_drv_systick_get
+ */
+typedef struct {
+    uint32_t time; //!< Registered time value
+}nrf_drv_systick_state_t;
+
+/**
+ * @brief Configure and start the timer
+ *
+ * Function configures SysTick as a free-running timer without interrupt.
+ */
+void nrf_drv_systick_init(void);
+
+/**
+ * @brief Get current SysTick state
+ *
+ * Function gets current state of the SysTick timer.
+ * It can be used to check time-out by @ref nrf_drv_systick_test.
+ *
+ * @param[out] p_state The pointer to the state variable to be filled
+ */
+void nrf_drv_systick_get(nrf_drv_systick_state_t * p_state);
+
+/**
+ * @brief Test if specified time is up in relation to remembered state
+ *
+ * @param[in] p_state Remembered state set by @ref nrf_drv_systick_get
+ * @param[in] us      Required time-out.
+ *
+ * @retval true  If current time is higher than specified state plus given time-out.
+ * @retval false If current time is lower than specified state plus given time-out
+ */
+bool nrf_drv_systick_test(nrf_drv_systick_state_t const * p_state, uint32_t us);
+
+/**
+ * @brief Blocking delay in CPU ticks
+ *
+ * @param[in] ticks Number of CPU ticks to delay.
+ */
+void nrf_drv_systick_delay_ticks(uint32_t ticks);
+
+/**
+ * @brief Blocking delay in us
+ *
+ * @param[in] us Number of microseconds to delay.
+ */
+void nrf_drv_systick_delay_us(uint32_t us);
+
+/**
+ * @brief Blocking delay in ms
+ *
+ * This delay function removes the limits of the highest possible delay value.
+ *
+ * @param[in] ms Number of milliseconds to delay.
+ */
+void nrf_drv_systick_delay_ms(uint32_t ms);
+
+
+/** @} */
+#endif /* NRF_DRV_SYSTICK_H__ */