Rainbow Electronics AT73C246 - Manual (Page 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.