I am trying to use sounds and audio in my EVE application. The code looks correct but I cannot hear any sound output.

EVE outputs the audio signal via the Audio_L pin. This goes into an external amplifier circuit and then on to the speaker. Many development modules for EVE include the amplifier on the PCB and either an on-board speaker or a connector for an external speaker. Here are some things to check:

• Check all connections and that the external speaker (if used) is of a suitable impedance for the amplifier used
• Check that any jumpers on the board are set to power up the amplifier
• Check that the power source used has sufficient current capability (due to the display backlight and audio circuit, the overall display module can require quite a lot of current, often several hundred milliamps or more)
• Ensure the audio amplifier is not in the power-down state. Many evaluation modules have a power-down signal controlled by a GPIO line on EVE to power down the amplifier when not used. Check that the GPIO and GPIO Direction registers in EVE have this GPIO line set as output and to the correct state to enable the amplifier.
• Ensure the volume has not been turned down. Volume is controlled by REG_VOL_SOUND for sounds and REG_VOL_PB for playback of audio. A value of 0xFF is highest whilst a value of 0x00 is muted.