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# Release Notes for WM8994 Component Driver

Copyright 2016 STMicroelectronics

## Update History

### V2.2.1 / 24-January-2018

Main Changes

- Fix output device headphone initialization issue

### V2.2.0 / 05-June-2017

Main Changes

- Add support of ColdStartup sequence for headphone
- Unmute is performed in a gradual way to minimize pop noise.
- Update wm8994_SetFrequency to support AUDIO_FREQUENCY_32K
- Update comments to be used for PDSC generation

### V2.1.0 / 22-February-2016

Main Changes

- wm8994.c

- Update wm8994_Init() by adding the support of analog microphone connected to INPUT LINE 1, INPUT_DEVICE_DIGITAL_MICROPHONE_1 and INPUT_DEVICE_DIGITAL_MIC1_MIC2
- Add AUDIO_FREQUENCY_32K as possible AudioFreq value

- wm8994.h

- Add INPUT_DEVICE_DIGITAL_MIC1_MIC2 define

### V2.0.0 / 24-June-2015

Main Changes

- wm8994.h

- Add codec de-initialization function: wm8994_DeInit()
- Add Audio IO de-initialization function prototype: AUDIO_IO_DeInit()
- Add INPUT_DEVICE_INPUT_LINE_1 and INPUT_DEVICE_INPUT_LINE_1 support for AUDIO IN
- Add Input audio volume control support

- wm8994.c

- Update wm8994_Init() function to support the Audio IN
- Update wm8994_Stop() function to only stop the codec if it was configured
- Enable VMID_BUF_ENA bit in R57 ANTIPOP register (address 0x39) for all configurations

- NOTE: This release must be used with BSP Common driver V4.0.0 or later

### V1.0.2 / 12-February-2015

Main Changes

- wm8994.c: Update the wm8994_Init() function to set the volume after enabling the dynamic charge pump power control mode

### V1.0.1 / 28-November-2014

Main Changes

- wm8994.h: change "\" by "/" in the include path to fix compilation issue with Linux

### V1.0.0 / 18-February-2014

Main Changes

- First official release of WM8994 AUDIO component driver

## 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. Neither the name of STMicroelectronics nor the names of its contributors may be used to endorse or promote products derived

from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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.

For complete documentation on STM32 Microcontrollers visit www.st.com/STM32