Samsung S3C2451X User Manual page 694

AC97 CONTROLLER
OPERATION FLOW CHART
When you initialize the AC97 controller, you must assert system reset or cold reset. Because we don't know the
previous state of the external the AC97 audio-codec. This assumes that GPIO is already ready. Then you make
codec ready interrupt enable. You can check codec ready interrupt by polling or interrupt. When interrupt is
occurred, you must de-assert codec ready interrupt. Now then you can transmit data from memory to register, or
from register to memory by using DMA or PIO(directly to write data to register). If internal FIFOs (TX FIFO or RX
FIFO) is not empty, then let data be transmitted. In addition, you can previously turn on AC-Link.
Time out condition ?
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
27-4
Specifications and information herein are subject to change without notice.
No
Yes
Controller off
Figure 27-3. AC97 Operation Flow Chart
System reset or Cold reset
Set GPIO and Release
INTMSK/SUBINTMSK bits
Enable Codec Ready interrupt
No
Codec Ready interrupt ?
Disable Codec Ready interrupt
DMA operation or
PIO (Interrupt or Polling) operation
S3C2451 RISC MICROPROCESSOR