
PRELIMINARY
AC97 CONTROLLER
S3C6400 RISC MICROPROCESSOR
35-6
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
AC-LINK OUTPUT FRAME (SDATA_OUT)
Slot 0: Tag Phase
In slot 0, the first bit is a bit (SDATA_OUT, bit 15) which represents the validity of the entire frame. If bit 15 is a 1,
the current frame contains at least a valid time slot. The next 12 bit positions correspond each 12 time slot
contains valid data. Bits 0 and 1 of slot 0 are used as CODEC IO bits for I/O reads and writes to the CODEC
registers as described in the next section. In this way, data streams of differing sample rate can be transmitted
across AC-link at its fixed 48kHz audio frame rate.
Slot 1: Command Address Port
In slot 1, it communicates control register address and write/read command information to the AC97 controller.
When software accesses the primary CODEC, the hardware configures the frame as follows :
- In slot 0, the valid bit for 1, 2 slots are set.
- In slot 1, bit 19 is set (read) or clear(write). Bits 18-12 (of slot 1) are configured to specify the index to the
CODEC register. Others are filled with 0’s(reserved).
- In slot 2, it configured with the data which is for writing because of output frame.
Slot 2: Command Data Port
In slot 2, this is the write data with 16-bit resolution.([19:4] is valid data)
Slot 3: PCM Playback Left channel
Slot 3 which is audio output frame is the composite digital audio left stream. If a sample has a resolution that is
less than 16 bits, the AC97 controller fills all training non-valid bit positions in the slot with zeroes.
Slot 4: PCM Playback Right channel
Slot 4 which is audio output frame is the composite digital audio right stream. If a sample has a resolution that is
less than 16 bits, the AC97 controller fills all training non-valid bit positions in the slot with zeroes.
SDATA_OUT
BIT_CLK
SYNC
AC '97 samples SYNC assertion here
AC '97 Controller samples first SDATA_OUT bit of frame here
END of previous Audio Frame
Valid
Frame
Slot(1)
Slot(2)
Slot(12)
"0"
ID1
ID0
19
0
Tag Phase
Data Phase
19
0
START of Data phase
Slot# 1
END of Data Frame
Slot# 12
48KHz
12.288MHz
Figure 35-5. AC-link Output Frame