Rainbow-electronics AT73C246 Manual do Utilizador descarregar pdf (Página 135)

135

11050A–PMAAC–07-Apr-10

AT73C246

// Wait (3.tau) = 300ms with 1uF before standby release. (VMID will be

// discharged only when ENAC = 0.)

// From this point Audio Data can be sent over the Digital audio interface.

TWI_WRITE 0x61 @ AUTOSTART.

WAIT 300ms

// Release standby. The audio codec starts silently, the gains are slowly

// ramped up from mute to the register gains. The codec is active.

TWI_WRITE 0x41 @ AUTOSTART

// Codec Pause by Standby

// All gains are softly ramped down to mute. The codec functions are

// shut down. Current consumption is reduced to a few hundreds of micro-

// amps. VMID remains charged

TWI_WRITE 0x61 @ AUTOSTART

// Pause out: Standby release. The codec softly re-starts.

TWI_WRITE 0x41 @ AUTOSTART

// On-the-fly path change

// PATH = 19: Digital IN to Headphone OUT + Mic IN to Digital OUT.

// The codec controller powers up automatically the new path. The DAC

// playback is not affected by starting the Mic. recording.

TWI_WRITE 0x52 @ AUTOSTART

// Codec Shutdown. ENAC = 0, STANDBY = 1. The codec turns off smoothly.

// In case of AC Coupling output configuration, HPR & HPL will slowly

// discharge following VMID time constant.

TWI_WRITE 0x20 @ AUTOSTART

WAIT 600ms

// Disable DCBLOCK bit.

TWI_WRITE 0x07 @ AUDIO_CONTROL

// LDO4 shutdown.

TWI_WRITE 0x0C @ VDD4_CONTROL

14.2.2 Basic Audio Codec Setting Using Custom Path Control

The following example demonstrates a custom audio path setting. Assuming that the audio

codec is supplied by the LDO4, the sequence is the following:

• Make the codec analog and digital interfaces configuration,

• Enter the custom path mode and configure a path with DAC input and Headphone Amplifier

output,

• Put the audio codec in standby mode,

• Release the standby mode to re-activate the selected path,

• Change the path on-the-fly to add the microphone inputs to the DAC signal,

• Shutdown the codec.

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Rainbow-electronics AT73C246 Manual do Utilizador Página 135