DAC API指南
======

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--------------


DAC
------------

概述
~~~~~~~~~~~~~~~~

数模转换器（digital-to-analog converter，通常称为DAC）是一种数字与模拟转换器，，FIFO深度为1，支持2路DAC调制输出。 可用于音频播放，常规的模拟信号调制。


API参考
~~~~~~~~~~~~~~~~

Header File
:::::::
components/platform/hosal/include/hosal_dac.h

Functions
:::::::

.. code-block:: c

   int hosal_dac_init(hosal_dac_dev_t *dac)
Initialises an dac interface.
   
   ``return``
  - 0 on success
  - EIO if an error occurred with any step

   ``Parameters``
  - dac: the interface which should be initialised


.. code-block:: c

   int hosal_dac_finalize(hosal_dac_dev_t *dac)

De-initialises an dac interface, Turns off an dac hardware interface.

   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - dac: the interface which should be de-initialised



.. code-block:: c

   int hosal_dac_start(hosal_dac_dev_t *dac)

Start output dac （no DMA mode）

   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - dac: the interface which should be started



.. code-block:: c

  int hosal_dac_stop(hosal_dac_dev_t *dac)

Stop output dac.
             
   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - dac: the interface which should be stopped


.. code-block:: c

  int hosal_dac_set_value(hosal_dac_dev_t *dac, uint32_t data)

Output a value to an dac interface.

   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - dac: the interface to set value
  - data: the value to output, output unit: μV


.. code-block:: c

  int hosal_dac_get_value(hosal_dac_dev_t *dac)

Returns the last data output value of the selected dac channel.

    ``return``
  - dac output value, output unit: μV
  
    ``Parameters``
  - dac: the interface to get value


.. code-block:: c

  int hosal_dac_dma_cb_reg(hosal_dac_dev_t *dac, hosal_dac_cb_t callback, void *arg)

DAC cb register.

   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - dac: the DAC interface
  - callback: callback handler
  - arg: callback arg



.. code-block:: c

  int hosal_dac_dma_start(hosal_dac_dev_t *dac, uint32_t *data, uint32_t size)

DAC use DMA mode.

   ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
   ``Parameters``
  - adc: the DAC interface
  - data: dac data buffer
  - size: data buffer size


.. code-block:: c

  int hosal_dac_dma_stop(hosal_dac_dev_t *dac)

Stop output dac.

    ``return``
  - 0 on success
  - EIO if an error occurred with any step
  
    ``Parameters``
  - dac: the interface which should be stopped


Structures
:::::::

.. code-block:: c

  struct hosal_dac_config_t

This struct define dac config args.

   Public Members

   ``uint8_t dma_enable``
      1: use dma, 0: no dma
   ``uint32_t pin``
      dac pin
   ``uint32_t freq``
     dac freq


.. code-block:: c

 struct hosal_dac_dev_t

This struct define dac device type.

   Public Members

   ``uint8_t port``
      dac id
   ``hosal_dac_config_t config``
      dac config
   ``hosal_dac_cb_t cb``
     dma callback
   ``hosal_dma_chan_t dma_chan``
      dac dma channel
   ``void *arg``
      arg data
   ``void *priv``
     priv data


Type Definitions
:::::::

.. code-block:: c

 typedef void (*hosal_dac_cb_t)(void *arg)

hosal dac callback

   ``Parameters``
     arg: Set the custom parameters specified when the callback function is set