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hal/lp_ticker_api.h
- Committer:
- kevman
- Date:
- 2018-11-28
- Revision:
- 0:38ceb79fef03
File content as of revision 0:38ceb79fef03:
/** \addtogroup hal */ /** @{*/ /* mbed Microcontroller Library * Copyright (c) 2015 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef MBED_LPTICKER_API_H #define MBED_LPTICKER_API_H #include "device.h" #if DEVICE_LPTICKER #include "hal/ticker_api.h" #ifdef __cplusplus extern "C" { #endif /** * \defgroup hal_lp_ticker Low Power Ticker * Low level interface to the low power ticker of a target * * # Defined behavior * * Has a reported frequency between 4KHz and 64KHz - verified by ::lp_ticker_info_test * * Has a counter that is at least 12 bits wide - verified by ::lp_ticker_info_test * * Continues operating in deep sleep mode - verified by ::lp_ticker_deepsleep_test * * All behavior defined by the @ref hal_ticker_shared "ticker specification" * * # Undefined behavior * * See the @ref hal_ticker_shared "ticker specification" * * Calling any function other than lp_ticker_init after calling lp_ticker_free * * # Potential bugs * * Glitches due to ripple counter - Verified by ::lp_ticker_glitch_test * * @see hal_lp_ticker_tests * * @{ */ /** * \defgroup hal_lp_ticker_tests Low Power Ticker tests * Tests to validate the proper implementation of the low power ticker * * To run the low power ticker hal tests use the command: * * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-common_ticker*,tests-mbed_hal-lp_ticker* * */ typedef void (*ticker_irq_handler_type)(const ticker_data_t *const); /** Set low power ticker IRQ handler * * @param ticker_irq_handler IRQ handler to be connected * * @return previous ticker IRQ handler * * @note by default IRQ handler is set to ::ticker_irq_handler * @note this function is primarily for testing purposes and it's not required part of HAL implementation * */ ticker_irq_handler_type set_lp_ticker_irq_handler(ticker_irq_handler_type ticker_irq_handler); /** Get low power ticker's data * * @return The low power ticker data */ const ticker_data_t *get_lp_ticker_data(void); /** The wrapper for ticker_irq_handler, to pass lp ticker's data * */ void lp_ticker_irq_handler(void); /* HAL lp ticker */ /** Initialize the low power ticker * * Initialize or re-initialize the ticker. This resets all the * clocking and prescaler registers, along with disabling * the compare interrupt. * * Pseudo Code: * @code * void lp_ticker_init() * { * // Enable clock gate so processor can read LPTMR registers * POWER_CTRL |= POWER_CTRL_LPTMR_Msk; * * // Disable the timer and ensure it is powered down * LPTMR_CTRL &= ~(LPTMR_CTRL_ENABLE_Msk | LPTMR_CTRL_COMPARE_ENABLE_Msk); * * // Configure divisors - no division necessary * LPTMR_PRESCALE = 0; * LPTMR_CTRL |= LPTMR_CTRL_ENABLE_Msk; * * // Install the interrupt handler * NVIC_SetVector(LPTMR_IRQn, (uint32_t)lp_ticker_irq_handler); * NVIC_EnableIRQ(LPTMR_IRQn); * } * @endcode */ void lp_ticker_init(void); /** Deinitialize the lower power ticker * * Powerdown the lp ticker in preparation for sleep, powerdown, or reset. * * After calling this function no other ticker functions should be called except * lp_ticker_init(). Calling any function other than init after freeing is * undefined. * * @note This function stops the ticker from counting. */ void lp_ticker_free(void); /** Read the current tick * * If no rollover has occurred, the seconds passed since lp_ticker_init() * was called can be found by dividing the ticks returned by this function * by the frequency returned by ::lp_ticker_get_info. * * @return The current timer's counter value in ticks * * Pseudo Code: * @code * uint32_t lp_ticker_read() * { * uint16_t count; * uint16_t last_count; * * // Loop until the same tick is read twice since this * // is ripple counter on a different clock domain. * count = LPTMR_COUNT; * do { * last_count = count; * count = LPTMR_COUNT; * } while (last_count != count); * * return count; * } * @endcode */ uint32_t lp_ticker_read(void); /** Set interrupt for specified timestamp * * @param timestamp The time in ticks to be set * * @note no special handling needs to be done for times in the past * as the common timer code will detect this and call * lp_ticker_fire_interrupt() if this is the case * * @note calling this function with timestamp of more than the supported * number of bits returned by ::lp_ticker_get_info results in undefined * behavior. * * Pseudo Code: * @code * void lp_ticker_set_interrupt(timestamp_t timestamp) * { * LPTMR_COMPARE = timestamp; * LPTMR_CTRL |= LPTMR_CTRL_COMPARE_ENABLE_Msk; * } * @endcode */ void lp_ticker_set_interrupt(timestamp_t timestamp); /** Disable low power ticker interrupt * * Pseudo Code: * @code * void lp_ticker_disable_interrupt(void) * { * // Disable the compare interrupt * LPTMR_CTRL &= ~LPTMR_CTRL_COMPARE_ENABLE_Msk; * } * @endcode */ void lp_ticker_disable_interrupt(void); /** Clear the low power ticker interrupt * * Pseudo Code: * @code * void lp_ticker_clear_interrupt(void) * { * // Write to the ICR (interrupt clear register) of the LPTMR * LPTMR_ICR = LPTMR_ICR_COMPARE_Msk; * } * @endcode */ void lp_ticker_clear_interrupt(void); /** Set pending interrupt that should be fired right away. * * Pseudo Code: * @code * void lp_ticker_fire_interrupt(void) * { * NVIC_SetPendingIRQ(LPTMR_IRQn); * } * @endcode */ void lp_ticker_fire_interrupt(void); /** Get frequency and counter bits of this ticker. * * Pseudo Code: * @code * const ticker_info_t* lp_ticker_get_info() * { * static const ticker_info_t info = { * 32768, // 32KHz * 16 // 16 bit counter * }; * return &info; * } * @endcode */ const ticker_info_t *lp_ticker_get_info(void); /**@}*/ #ifdef __cplusplus } #endif #endif #endif /** @}*/