alc272 Realtek Semiconductor Corporation, alc272 Datasheet - Page 26

• Manufacturer Part Number: alc272
• Description: 4 Channel High Definition Audio Codec
• Manufacturer: Realtek Semiconductor Corporation

7.3. Reset and Initialization
There are two types of reset within an HDA link:
• Link Reset
• Codec Reset
An initialization sequence is requested after any of the following three events:
• Link Reset
• Codec Reset
• Codec changes its power state, e.g., hot docking a codec to an HDA system
7.3.1.
A link reset may be caused by any of the following three events:
1. The HDA controller asserts RESET# for any reason (power up, or PCI reset)
2. Software initiates a link reset via the ‘CRST’ bit in the Global Control Register (GCR) of the HDA
controller
3. Software initiates power management sequences. Figure 12, page 19, shows the ‘Link Reset’ timing
including the ‘Enter’ sequence ( ~ ) and ‘Exit’ sequence ( ~ )
Enter ‘Link Reset’:
link reset
end of the frame
4 Channel High Definition Audio Codec
Software writes a 0 to the ‘CRST’ bit in the Global Control Register of the HDA controller to initiate a
The controller drives SYNC and all SDOs to low. Codecs also drive SDIs to low
The controller asserts the RESET# signal to low, and enters the ‘Link Reset’ state
All link signals driven by controller and codecs should be tri-state by internal pull-low resistors
As the controller completes the current frame, it does not signal the normal 8-bit frame SYNC at the
Generated by assertion of the RESET# signal. All codecs return to their power-on state
Generated by software directing a command to reset a specific codec back to its default state
Link Reset
18
Track ID: JATR-1076-21
Datasheet
ALC272
Rev. 1.0