+/**
+ * ADC ISR callback.
+ * This function has to be called by the ADC ISR when a sample of the configured
+ * channel is available.
+ * \param af Afsk context to operate one (\see Afsk).
+ * \param sample current sample from the ADC.
+ */
+void afsk_adc_isr(Afsk *af, int8_t sample);
+
+/**
+ * DAC ISR callback.
+ * This function has to be called by the DAC ISR when a sample of the configured
+ * channel has been converted out.
+ *
+ * \param af Afsk context to operate one (\see Afsk).
+ *
+ * \note The next DAC output sample is supplied by the Afsk driver through calling
+ * the AFSK_DAC_SET() callback.
+ */