t
Fork of mbed-dev by
Diff: targets/TARGET_Atmel/TARGET_SAM_CortexM0P/drivers/dac/TARGET_SAMD21/dac_feature.h
- Revision:
- 149:156823d33999
- Parent:
- 18:da299f395b9e
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/TARGET_Atmel/TARGET_SAM_CortexM0P/drivers/dac/TARGET_SAMD21/dac_feature.h Fri Oct 28 11:17:30 2016 +0100 @@ -0,0 +1,635 @@ +/** + * \file + * + * \brief SAM Peripheral Digital-to-Analog Converter Driver + * + * Copyright (C) 2012-2015 Atmel Corporation. All rights reserved. + * + * \asf_license_start + * + * \page License + * + * 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 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. The name of Atmel may not be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * 4. This software may only be redistributed and used in connection with an + * Atmel microcontroller product. + * + * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE + * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL 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. + * + * \asf_license_stop + * + */ +/* + * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a> + */ +#ifndef DAC_FEATURE_H_INCLUDED +#define DAC_FEATURE_H_INCLUDED + +/** + * \defgroup asfdoc_sam0_dac_group SAM Digital-to-Analog Driver (DAC) + * + * This driver for Atmel® | SMART ARM®-based microcontrollers provides an interface for the conversion of + * digital values to analog voltage. The following driver API modes are covered + * by this manual: + * + * - Polled APIs + * \if DAC_CALLBACK_MODE + * - Callback APIs + * \endif + * + * The following peripherals are used by this module: + * - DAC (Digital-to-Analog Converter) + * + * The following devices can use this module: + * - Atmel | SMART SAM D20/D21 + * - Atmel | SMART SAM D10/D11 + * - Atmel | SMART SAM DA0/DA1 + * - Atmel | SMART SAM C21 + * + * The outline of this documentation is as follows: + * - \ref asfdoc_sam0_dac_prerequisites + * - \ref asfdoc_sam0_dac_module_overview + * - \ref asfdoc_sam0_dac_special_considerations + * - \ref asfdoc_sam0_dac_extra_info + * - \ref asfdoc_sam0_dac_examples + * - \ref asfdoc_sam0_dac_api_overview + * + * + * \section asfdoc_sam0_dac_prerequisites Prerequisites + * + * There are no prerequisites for this module. + * + * + * \section asfdoc_sam0_dac_module_overview Module Overview + * + * The Digital-to-Analog converter converts a digital value to analog voltage. + * The SAM DAC module has one channel with 10-bit resolution, + * and is capable of converting up to 350k samples per second (ksps). + * + * A common use of DAC is to generate audio signals by connecting the DAC + * output to a speaker, or to generate a reference voltage; either for an + * external circuit or an internal peripheral such as the Analog Comparator. + * + * After being set up, the DAC will convert new digital values written to the + * conversion data register (DATA) to an analog value either on the VOUT pin of + * the device, or internally for use as an input to the AC, ADC, and other analog + * modules. + * + * Writing the DATA register will start a new conversion. It is also possible + * to trigger the conversion from the event system. + * + * A simplified block diagram of the DAC can be seen in + * \ref asfdoc_sam0_dac_module_block_diagram "the figure below". + * + * \anchor asfdoc_sam0_dac_module_block_diagram + * \image html dac_block_diagram.svg "DAC Block Diagram" + * + * \subsection asfdoc_sam0_dac_conversion_range Conversion Range + * The conversion range is between GND and the selected voltage reference. + * Available voltage references are: + * \li AVCC voltage reference + * \li Internal 1V reference (INT1V) + * \li External voltage reference (AREF) + * + * \note Internal references will be enabled by the driver, but not disabled. + * Any reference not used by the application should be disabled by the application. + * + * The output voltage from a DAC channel is given as: + * \f[ + * V_{OUT} = \frac{DATA}{0x3FF} \times VREF + * \f] + * + * \subsection asfdoc_sam0_dac_conversion Conversion + * The digital value written to the conversion data register (DATA) will be + * converted to an analog value. + * Writing the DATA register will start a new conversion. + * It is also possible to write the conversion data to the DATABUF register, + * the writing of the DATA register can then be triggered from the event + * system, which will load the value from DATABUF to DATA. + * + * \subsection asfdoc_sam0_dac_analog_output Analog Output + * The analog output value can be output to either the VOUT pin or internally, + * but not both at the same time. + * + * \subsubsection asfdoc_sam0_dac_analog_output_external External Output + * The output buffer must be enabled in order to drive the DAC output to the + * VOUT pin. Due to the output buffer, the DAC has high drive strength, and is + * capable of driving both resistive and capacitive loads, as well as loads + * which combine both. + * + * \subsubsection asfdoc_sam0_dac_analog_output_internal Internal Output + * The analog value can be internally available for use as input to the + * AC or ADC modules. + * + * \subsection asfdoc_sam0_dac_events Events + * Events generation and event actions are configurable in the DAC. + * The DAC has one event line input and one event output: <i>Start Conversion</i> + * and <i>Data Buffer Empty</i>. + * + * If the Start Conversion input event is enabled in the module configuration, + * an incoming event will load data from the data buffer to the data register + * and start a new conversion. This method synchronizes conversions with + * external events (such as those from a timer module) and ensures regular and + * fixed conversion intervals. + * + * If the Data Buffer Empty output event is enabled in the module configuration, + * events will be generated when the DAC data buffer register becomes empty and + * new data can be loaded to the buffer. + * + * \note The connection of events between modules requires the use of the + * \ref asfdoc_sam0_events_group "SAM Event System Driver (EVENTS)" + * to route output event of one module to the the input event of another. + * For more information on event routing, refer to the event driver + * documentation. + * + * \subsection asfdoc_sam0_dac_data_adjust Left and Right Adjusted Values + * The 10-bit input value to the DAC is contained in a 16-bit register. This + * can be configured to be either left or right adjusted. In + * \ref asfdoc_sam0_dac_module_adj_modes "the figure below" both options are + * shown, and the position of the most (MSB) and the least (LSB) significant bits + * are indicated. The unused bits should always be written to zero. + * + * \anchor asfdoc_sam0_dac_module_adj_modes + * \dot + * digraph { + * subgraph cluster_right { + * msbl [label="MSB", shape=none, group="msbl"]; + * lsbl [label="LSB", shape=none]; + * node [shape=none]; + * color="white"; + * reg_left [label=< + * <table cellspacing="0" cellpadding="2" width="100%"> + * <tr> + * <td port="msb">15</td> + * <td>14</td> + * <td>13</td> + * <td>12</td> + * <td>11</td> + * <td>10</td> + * <td>9</td> + * <td>8</td> + * <td>7</td> + * <td port="lsb">6</td> + * <td>5</td> + * <td>4</td> + * <td>3</td> + * <td>2</td> + * <td>1</td> + * <td>0</td> + * </tr> + * <tr> + * <td COLSPAN="10"> DATA[9:0] </td> + * <td BGCOLOR="lightgray"> </td> + * <td BGCOLOR="lightgray"> </td> + * <td BGCOLOR="lightgray"> </td> + * <td BGCOLOR="lightgray"> </td> + * <td BGCOLOR="lightgray"> </td> + * <td BGCOLOR="lightgray"> </td> + * </tr> + * </table> + * >]; + * msbl -> reg_left:msb:n; + * lsbl -> reg_left:lsb; + * label ="Left adjusted.\n"; + * } + * subgraph cluster_left { + * rankdir=TB; + * msb [label="MSB", shape=none]; + * lsb [label="LSB", shape=none]; + * color="white"; + * node [shape=none]; + * reg_right [label=< + * <table cellspacing="0" cellpadding="2"> + * <tr> + * <td>15</td> + * <td>14</td> + * <td>13</td> + * <td>12</td> + * <td>11</td> + * <td>10</td> + * <td port="msb">9</td> + * <td>8</td> + * <td>7</td> + * <td>6</td> + * <td>5</td> + * <td>4</td> + * <td>3</td> + * <td>2</td> + * <td>1</td> + * <td port="lsb">0</td> + * </tr> + * <tr> + * <td BGCOLOR="lightgray"></td> + * <td BGCOLOR="lightgray"></td> + * <td BGCOLOR="lightgray"></td> + * <td BGCOLOR="lightgray"></td> + * <td BGCOLOR="lightgray"></td> + * <td BGCOLOR="lightgray"></td> + * <td COLSPAN="10"> DATA[9:0] </td> + * </tr> + * </table> + * >]; + * msb -> reg_right:msb; + * lsb -> reg_right:lsb:n; + * label = "Right adjusted.\n"; + * graph [shape=none]; + * } + * } + * \enddot + * + * \subsection asfdoc_sam0_dac_clk_sources Clock Sources + * The clock for the DAC interface (CLK_DAC) is generated by the Power Manager. + * This clock is turned on by default, and can be enabled and disabled in the + * Power Manager. + * + * Additionally, an asynchronous clock source (GCLK_DAC) is required. + * These clocks are normally disabled by default. The selected clock source + * must be enabled in the Power Manager before it can be used by the DAC. + * The DAC core operates asynchronously from the user interface and + * peripheral bus. As a consequence, the DAC needs two clock cycles of both + * CLK_DAC and GCLK_DAC to synchronize the values written to some of the + * control and data registers. + * The oscillator source for the GCLK_DAC clock is selected in the System + * Control Interface (SCIF). + * + * \section asfdoc_sam0_dac_special_considerations Special Considerations + * + * \subsection asfdoc_sam0_dac_special_considerations_output_buffer Output Driver + * The DAC can only do conversions in Active or Idle modes. However, if the + * output buffer is enabled it will draw current even if the system is in + * sleep mode. Therefore, always make sure that the output buffer is not + * enabled when it is not needed, to ensure minimum power consumption. + * + * \subsection asfdoc_sam0_dac_special_considerations_conversion_time Conversion Time + * DAC conversion time is approximately 2.85µs. The user must ensure that new + * data is not written to the DAC before the last conversion is complete. + * Conversions should be triggered by a periodic event from a Timer/Counter or + * another peripheral. + * + * + * \section asfdoc_sam0_dac_extra_info Extra Information + * + * For extra information, see \ref asfdoc_sam0_dac_extra. This includes: + * - \ref asfdoc_sam0_dac_extra_acronyms + * - \ref asfdoc_sam0_dac_extra_dependencies + * - \ref asfdoc_sam0_dac_extra_errata + * - \ref asfdoc_sam0_dac_extra_history + * + * + * \section asfdoc_sam0_dac_examples Examples + * + * For a list of examples related to this driver, see + * \ref asfdoc_sam0_dac_exqsg. + * + * + * \section asfdoc_sam0_dac_api_overview API Overview + * @{ + */ + +#ifdef __cplusplus +extern "C" { +#endif + +#include <compiler.h> +#include <clock.h> +#include <gclk.h> + + +/** + * \name DAC Status Flags + * + * DAC status flags, returned by \ref dac_get_status() and cleared by + * \ref dac_clear_status(). + * @{ + */ + +/** Data Buffer Empty Channel 0 - Set when data is transferred from DATABUF + * to DATA by a start conversion event and DATABUF is ready for new data. + */ +#define DAC_STATUS_CHANNEL_0_EMPTY (1UL << 0) + +/** Under-run Channel 0 - Set when a start conversion event occurs when + * DATABUF is empty. + */ +#define DAC_STATUS_CHANNEL_0_UNDERRUN (1UL << 1) + +/** @} */ + +/** + * \brief DAC reference voltage enum. + * + * Enum for the possible reference voltages for the DAC. + */ +enum dac_reference { + /** 1V from the internal band-gap reference.*/ + DAC_REFERENCE_INT1V = DAC_CTRLB_REFSEL(0), + /** Analog V<SUB>CC</SUB> as reference. */ + DAC_REFERENCE_AVCC = DAC_CTRLB_REFSEL(1), + /** External reference on AREF. */ + DAC_REFERENCE_AREF = DAC_CTRLB_REFSEL(2), +}; + +/** + * \brief DAC output selection enum. + * + * Enum for the DAC output selection. + */ +enum dac_output { + /** DAC output to VOUT pin */ + DAC_OUTPUT_EXTERNAL = DAC_CTRLB_EOEN, + /** DAC output as internal reference */ + DAC_OUTPUT_INTERNAL = DAC_CTRLB_IOEN, + /** No output */ + DAC_OUTPUT_NONE = 0, +}; + +/** + * \brief DAC channel selection enum. + * + * Enum for the DAC channel selection. + */ +enum dac_channel { + /** DAC output channel 0. */ + DAC_CHANNEL_0, +}; + +/** + * \brief DAC software device instance structure. + * + * DAC software instance structure, used to retain software state information + * of an associated hardware module instance. + * + * \note The fields of this structure should not be altered by the user + * application; they are reserved for module-internal use only. + */ +struct dac_module { +#if !defined(__DOXYGEN__) + /** DAC hardware module. */ + Dac *hw; + /** DAC output selection. */ + enum dac_output output; + /** Reference selection. */ + enum dac_reference reference; + /** DAC event selection. */ + bool start_on_event; +# if DAC_CALLBACK_MODE == true + /** Pointer to buffer used for ADC results. */ + volatile uint16_t *job_buffer; + /** Remaining number of conversions in current job. */ + volatile uint16_t remaining_conversions; + /** Transferred number of conversions in current job. */ + volatile uint16_t transferred_conversions; + /** DAC callback enable. */ + bool callback_enable[DAC_CALLBACK_N]; + /** DAC registered callback functions. */ + dac_callback_t callback[DAC_CALLBACK_N]; + /** Holds the status of the ongoing or last conversion job. */ + volatile enum status_code job_status; +# endif +#endif +}; + +/** + * \brief DAC configuration structure. + * + * Configuration structure for a DAC instance. This structure should be + * initialized by the \ref dac_get_config_defaults() + * function before being modified by the user application. + */ +struct dac_config { + /** Reference voltage. */ + enum dac_reference reference; + /** Select DAC output. */ + enum dac_output output; + /** Left adjusted data. */ + bool left_adjust; + /** GCLK generator used to clock the peripheral. */ + enum gclk_generator clock_source; +#ifdef FEATURE_DAC_DATABUF_WRITE_PROTECTION + /** Bypass DATABUF write protection. */ + bool databuf_protection_bypass; +#endif + /** Voltage pump disable. */ + bool voltage_pump_disable; + /** + * The DAC behaves as in normal mode when the chip enters STANDBY sleep + * mode. + */ + bool run_in_standby; +#if (SAMC21) + /** Dither mode enable data. */ + bool dither_mode; +#endif +}; + +/** + * \brief DAC event enable/disable structure. + * + * Event flags for the DAC module. This is used to enable and + * disable events via \ref dac_enable_events() and \ref dac_disable_events(). + */ +struct dac_events { + /** Start a new DAC conversion. */ + bool on_event_start_conversion; + /** Enable event generation on data buffer empty. */ + bool generate_event_on_buffer_empty; +#if (SAMC21) + /** Enable the falling edge of the input event for DAC1. */ + bool generate_event_on_chan_falling_edge; +#endif +}; + +/** + * \brief DAC channel configuration structure + * + * Configuration for a DAC channel. This structure should be initialized by the + * \ref dac_chan_get_config_defaults() function before being modified by the + * user application. + */ +struct dac_chan_config { +#if !defined(__DOXYGEN__) + /** Dummy value to ensure the struct has at least one member. */ + uint8_t _dummy; +#endif +}; + +/** + * \name Configuration and Initialization (Channel) + * @{ + */ + +void dac_chan_enable_output_buffer( + struct dac_module *const dev_inst, + const enum dac_channel channel); + +void dac_chan_disable_output_buffer( + struct dac_module *const dev_inst, + const enum dac_channel channel); + +/** @} */ + +/** @} */ + +/** + * \page asfdoc_sam0_dac_extra Extra Information for DAC Driver + * + * \section asfdoc_sam0_dac_extra_acronyms Acronyms + * The table below presents the acronyms used in this module: + * + * <table> + * <tr> + * <th>Acronym</th> + * <th>Description</th> + * </tr> + * <tr> + * <td>ADC</td> + * <td>Analog-to-Digital Converter</td> + * </tr> + * <tr> + * <td>AC</td> + * <td>Analog Comparator</td> + * </tr> + * <tr> + * <td>DAC</td> + * <td>Digital-to-Analog Converter</td> + * </tr> + * <tr> + * <td>LSB</td> + * <td>Least Significant Bit</td> + * </tr> + * <tr> + * <td>MSB</td> + * <td>Most Significant Bit</td> + * </tr> + * <tr> + * <td>DMA</td> + * <td>Direct Memory Access</td> + * </tr> + * </table> + * + * + * \section asfdoc_sam0_dac_extra_dependencies Dependencies + * This driver has the following dependencies: + * + * - \ref asfdoc_sam0_system_pinmux_group "System Pin Multiplexer Driver" + * + * + * \section asfdoc_sam0_dac_extra_errata Errata + * There are no errata related to this driver. + * + * + * \section asfdoc_sam0_dac_extra_history Module History + * An overview of the module history is presented in the table below, with + * details on the enhancements and fixes made to the module since its first + * release. The current version of this corresponds to the newest version in + * the table. + * + * <table> + * <tr> + * <th>Changelog</th> + * </tr> + * <tr> + * <td>Add configuration for using 14-bit hardware dithering (SAMC21 support)</td> + * </tr> + * <tr> + * <td>Added new configuration parameters \c databuf_protection_bypass, + * \c voltage_pump_disable. Added new callback functions + * \c dac_chan_write_buffer_wait, + * \c dac_chan_write_buffer_job, \c dac_chan_write_job, + * \c dac_get_job_status, \c dac_abort_job and new callback type + * \c DAC_CALLBACK_TRANSFER_COMPLETE for DAC conversion job</td> + * </tr> + * <tr> + * <td>Initial Release</td> + * </tr> + * </table> + */ + +/** + * \page asfdoc_sam0_dac_exqsg Examples for DAC Driver + * + * This is a list of the available Quick Start guides (QSGs) and example + * applications for \ref asfdoc_sam0_dac_group. QSGs are simple examples with + * step-by-step instructions to configure and use this driver in a selection of + * use cases. Note that a QSG can be compiled as a standalone application or be + * added to the user application. + * + * - \subpage asfdoc_sam0_dac_basic_use_case + * \if DAC_CALLBACK_MODE + * - \subpage asfdoc_sam0_dac_basic_use_case_callback + * \endif + * \if DAC_DMA_USE_MODE_SELECTION + * - \subpage asfdoc_sam0_adc_dma_use_case_dac_in_dma + * \endif + * + * \if DAC_DMA_USE_MODE_SELECTION + * \page asfdoc_sam0_adc_dma_use_case_dac_in_dma Quick Start Guide for Using DMA with ADC/DAC + * For this examples, see + * \ref asfdoc_sam0_adc_dma_use_case + * \endif + * + * \page asfdoc_sam0_dac_document_revision_history Document Revision History + * + * <table> + * <tr> + * <th>Doc. Rev.</td> + * <th>Date</td> + * <th>Comments</td> + * </tr> + * <tr> + * <td>42110E</td> + * <td>06/2015</td> + * <td>Add SAMC21 and SAMDAx support</td> + * </tr> + * <tr> + * <td>42110D</td> + * <td>12/2014</td> + * <td>Add SAMD10/D11 support</td> + * </tr> + * <tr> + * <td>42110C</td> + * <td>01/2014</td> + * <td>Add SAMD21 support</td> + * </tr> + * <tr> + * <td>42110B</td> + * <td>06/2013</td> + * <td>Added additional documentation on the event system. Corrected + * documentation typos.</td> + * </tr> + * <tr> + * <td>42110A</td> + * <td>06/2013</td> + * <td>Initial document release</td> + * </tr> + * </table> + */ + +#ifdef __cplusplus +} +#endif + + +#endif /* DAC_FEATURE_H_INCLUDED */ +