FIQ_Handler

#include <demo.h>

void FIQ_Handler  (
  void);

The FIQ_Handler function outputs the audio data from the host to the speaker. the function is implemented as a fast interrupt request function that runs every 31.25 μs. It scales the audio data according to the volume and mute settings before writing the value to the speaker’s register. The function also calculates the loudness over 32 ms and outputs this using the LEDs.

Modify this function to suit the application product hardware.

The FIQ_Handler function is part of the Application layer of the RL-USB Software Stack.

Note

• The function starts to write (DataRun=1) to the speaker register when at least half the buffer (DataBuf) contains data. The function stops writing (DataRun=0) to the speaker register when no data are available in the buffer.

None.

ADC_IF_GetRequest, ADC_IF_SetRequest

#include <demo.h>

void FIQ_Handler (void)  {

  …
  val = DataBuf[DataOut];       // Get the audio data sent by the host
  …
  val *= volume;                // Adjust the data according to the volume
  …
  if (Mute)  {
    val = 0x8000;               // Change the data to mute value
  }

  DACR = val & 0xFFC0;          // Write the data to the speaker register
  …
}