D/A converter exercises

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DTMF generator

Use the two on-chip DACs to implement a DTMF generator. Two sinusoudal signals with different frequencies should be generated and superimposed using the DACs merge function. The sinusoudal signal pattern should consist of 64 samples of 8-bit data stored in an array, the DACs should be used in 8-bit mode. Use a timer to update the DACs and use the timer interrupt service routine to generate the signals for a given amount of time. Write a function that can generate a DTMF signal, the input parameters are: the key, the duration in milliseconds.