AN3143

Audio data encoding and storing

Doc ID 17011 Rev 1

7/13

Another way to store audio data to the internal memory is to link audio data arrays with the

compiled code. To include raw data in a project, a binary representation of the data have to

be converted to ASCII format. Any advanced HEX editor is able to export data in this format

which is then readable by ANSI C compilers. The TxD hexa editor (see References) is an

easy-to-use software, with a free license, no restrictions for commercial use, and which can

be freely distributed.

The processing of audio data, which have to be included in a project, consists of loading

binary data into the editor and exporting them as a C source code.

Figure 3.

The output of this operation is a C source file with one array:

unsigned char rawData[10340] = { ...

This declaration has to be modified, using compiler directives, into an array of constants in

the program memory. This is done for the COSMIC compiler as follows:

const @far unsigned char rawData[10340] = { ...

For the Raisonance compiler, the following directive has to be used:

fcode unsigned char rawData[10340] = { ...

For more details, see the firmware project associated with this application note on

www.st.com/mcu.