ES1371 Datasheet, PDF (29/37 Pages) List of Unclassifed Manufacturers – ENSONIQ AudioPCI 97 digital controller

ENSONIQ Proprietary Information
8. POWER MANAGEMENT
All power management of the system is under software control. The AC97 CODEC and AudioPCI 97 can
be powered down separately. Neither chip loses register information when powered down.
The AudioPCI 97 can be power managed by shutting down various sub-systems. The following blocks can
be individually powered down: Joystick, UART, and Serial Interface. Although these blocks can be
individually disabled this will not save an appreciable amount of power. AudioPCI 97 can also individually
internally shut down the PCI clock and the Crystal input clock. The PCI clock when shut down will still be
active to the PCI and Interrupt/Chip Select modules. The Crystal clock when shut down will be shut down
for all internal modules as well as the output connection to the AC97 CODEC.
During operation, the AudioPCI 97 ASIC will have a typical power dissipation of 150mW. In power down,
the AudioPCI 97 ASIC will have a typical power dissipation of 15mW.
8.1. CODEC Power Management
The AC97 CODEC’s are powered down by setting bit 1 (of control bits 7 - 0) in control register 16 (hex) to
a zero. The AC97 CODEC control registers are written through the CODEC Interface block at address 14
(hex). For details refer to the AC97 specification and also the CODEC Interface section (7.5) of this
specification.
8.2. AUDIOPCI Power Management
As mentioned above, the Joystick, UART, and Serial Interface modules of the AudioPCI 97 chip can be
individually powered down. The remaining modules will be in a powered up condition. The AudioPCI 97
modules are powered down by setting bits 6 - 2 (of control bits 31 - 0) to zero. The AudioPCI 97 control
register is located in the IRQ and Chip Select Block at address 00 (hex). For details refer to the IRQ and
Chip Select Block section (7.1) of this specification. Note that the Serial Interface actually has three
separate enable bits, one for each of the playback channels and one for the record channel.
Although these blocks can be individually disabled this will not save an appreciable amount of power.
AudioPCI 97 can also individually internally shut down the PCI clock and the Crystal input clock. The PCI
clock when shut down will still be active to the PCI and Interrupt/Chip Select modules. The Crystal clock
when shut down will be shut down for all internal modules as well as the output connection to the AC97
CODEC.
ENSONIQ Proprietary Information
ENSONIQ AudioPCI 97 Specification Rev 1.1 Oct 1, 1997
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