164 lines
5.3 KiB
C
164 lines
5.3 KiB
C
/**
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* \file
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*
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* \brief SAM Frequency Meter (FREQM) Driver
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*
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* Copyright (C) 2015-2016 Atmel Corporation. All rights reserved.
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*
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* \asf_license_start
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*
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* \page License
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. The name of Atmel may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* 4. This software may only be redistributed and used in connection with an
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* Atmel microcontroller product.
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*
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* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* \asf_license_stop
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*
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*/
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/*
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* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
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*/
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#include "freqm.h"
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#include <gclk.h>
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#ifndef FREQM_GCLK_ID_REF
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#define FREQM_GCLK_ID_REF (FREQM_GCLK_ID_MSR + 1)
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#endif
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/**
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* \brief Initializes a hardware FREQM module instance.
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*
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* Enables the clock and initializes the FREQM module, based on the given
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* configuration values.
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*
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* \param[in,out] module_inst Pointer to the software module instance struct
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* \param[in] hw Pointer to the FREQM hardware module
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* \param[in] config Pointer to the FREQM configuration options struct
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*
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* \return Status of the initialization procedure.
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*
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* \retval STATUS_OK The module was initialized successfully
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*/
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enum status_code freqm_init(
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struct freqm_module *const module_inst,
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Freqm *const hw,
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struct freqm_config *const config)
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{
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/* Sanity check arguments */
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Assert(module_inst);
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Assert(hw);
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Assert(config);
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Assert(config->ref_clock_circles);
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/* Initialize device instance */
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module_inst->hw = hw;
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/* Turn on the digital interface clock */
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system_apb_clock_set_mask(SYSTEM_CLOCK_APB_APBA, MCLK_APBAMASK_FREQM);
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/* Set up the GCLK for the module */
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struct system_gclk_chan_config gclk_chan_conf;
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system_gclk_chan_get_config_defaults(&gclk_chan_conf);
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gclk_chan_conf.source_generator = config->msr_clock_source;
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system_gclk_chan_set_config(FREQM_GCLK_ID_MSR, &gclk_chan_conf);
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system_gclk_chan_enable(FREQM_GCLK_ID_MSR);
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gclk_chan_conf.source_generator = config->ref_clock_source;
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system_gclk_chan_set_config(FREQM_GCLK_ID_REF, &gclk_chan_conf);
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system_gclk_chan_enable(FREQM_GCLK_ID_REF);
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module_inst->ref_clock_freq = system_gclk_gen_get_hz(config->ref_clock_source);
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/* Perform a software reset */
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hw->CTRLA.reg = FREQM_CTRLA_SWRST;
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while (freqm_is_syncing()) {
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/* Wait for all hardware modules to complete synchronization */
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}
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/* Initialize the FREQM with new configurations */
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hw->CFGA.reg = config->ref_clock_circles;
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#if FREQM_CALLBACK_MODE == true
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/* Initialize parameters */
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for (uint8_t i = 0; i < FREQM_CALLBACK_N; i++) {
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module_inst->callback[i] = NULL;
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}
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/* Register this instance for callbacks*/
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_freqm_instance = module_inst;
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#endif
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return STATUS_OK;
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}
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/**
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* \brief Read the measurement data result
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*
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* Reads the measurement data result.
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*
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* \param[in] module_inst Pointer to the FREQM software instance struct
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* \param[out] result Pointer to store the result value in
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*
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* \return Status of the FREQM read request.
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* \retval FREQM_STATUS_MEASURE_DONE Measurement result was retrieved successfully
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* \retval FREQM_STATUS_MEASURE_BUSY Measurement result was not ready
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* \retval FREQM_STATUS_CNT_OVERFLOW Measurement result was overflow
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*
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* \note If overflow occurred, configure faster reference clock or reduce reference clock cycles.
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*/
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enum freqm_status freqm_get_result_value(
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struct freqm_module *const module_inst, uint32_t *result)
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{
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/* Sanity check arguments */
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Assert(module_inst);
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Assert(module_inst->hw);
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Assert(result);
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Freqm *const freqm_hw = module_inst->hw;
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uint32_t result_cal;
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*result = result_cal= 0;
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if (freqm_hw->STATUS.reg & FREQM_STATUS_BUSY) {
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/* Result not ready */
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return FREQM_STATUS_MEASURE_BUSY;
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} else {
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if (freqm_hw->STATUS.reg & FREQM_STATUS_OVF) {
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/* Overflow */
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return FREQM_STATUS_CNT_OVERFLOW;
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} else {
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/* Get measurement output data (it will clear data done flag) */
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result_cal = freqm_hw->VALUE.reg;
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freqm_hw->INTFLAG.reg = FREQM_INTFLAG_DONE;
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*result = result_cal * module_inst->ref_clock_freq / freqm_hw->CFGA.reg;
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return FREQM_STATUS_MEASURE_DONE;
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}
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}
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}
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