AN3225

Conclusion

Doc ID 17566 Rev 3

11/13

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Conclusion

This application note offers a simple and ready-to-use application solution for the

STM8L/STM8AL with good quality audio/speech output.

The solution offered benefits from the STM8L/STM8AL on-chip DAC with a 12-bit resolution

and the advanced low-power modes of the STM8L/STM8AL microcontroller which are

aimed at battery-powered applications.

To adequately reduce memory space which allows an audio bitstream to be stored, an IMA

ADPCM codec is implemented. Short audio clips can be stored directly in the internal

program memory. To store long length audio clips, an external memory is needed. The SD

card was used as an example in this application note.

The STM8L/STM8AL audio output solution was developed with the aim to limit external

components. It is suitable for low cost applications.

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References

IMA Digital Audio Focus and Technical Working Group, Recommended Practices for

Enhancing Digital Audio Compatibility in Multimedia Systems, revision 3.00, October 21,

1992. No longer available on http://www.ima.org.

Maël Hörz, HxD, revision 1.7.7.0 - hexa editor, http://mh-nexus.de.