Ac-Link Input Frame (Sdata_In) - Samsung S3C2416 User Manual

S3C2416X RISC MICROPROCESSOR

4.2 AC-LINK INPUT FRAME (SDATA_IN)

Slot 0: Tag Phase
In slot 0, the first bit is a bit (SDATA_OUT, bit 15) that indicates whether the AC97 controller is in the CODEC
ready state. If the CODEC Ready bit is a 0, the AC97 controller is not ready for normal operation. This condition is
normal after the power is de-asserted on reset and the AC97 controller voltage references are settling.
Slot 1: Status Address Port/SLOTREQ bits
The status port monitors the status for the AC97 controller functions including, but not limited to, mixer settings
and power management. Audio input frame slot 1s stream echoes the control register index for the data to be
returned in slot 2, if the controller tags slots 1 and 2 as valid during slot 0. The controller only accepts status data
if the accompanying status address matches the last valid command address issued during the most recent read
command. For multiple sample rate output, the CODEC examines its sample-rate control registers, its FIFOs'
states, and the incoming SDATA_OUT tag bits at the beginning of each audio output frame to determine which
SLOTREQ bits to set active (low). SLOTREQ bits asserted during the current audio input frame indicate which
output slots require data from the controller in the next audio output frame. For fixed 48 kHz operation, the
SLOTREQ bits are set active (low), and a sample is transferred each frame. For multiple sample-rate input, the
"tag" bit for each input slot indicates whether valid data is present.
Bit
19
18-12
11
10
9
8
7
6
5
4
3
2
1, 0
Slot 2: Status Data Port
In slot 2, this is the status data with 16-bit resolution.([19:4] is valid data)
Slot 3: PCM Record Left channel
Slot 3 which is audio input frame is the left channel audio output of the AC97 Codec. If a sample has a resolution
that is less than 16 bits, the AC97 Codec fills all training non-valid bit positions in the slot with zeroes.
Table 24-1. Input Slot 1 Bit Definitions
RESERVED (Filled with zero)
Control register index (Filled with zeroes if AC97 tags is invalid)
Slot 3 request : PCM Left channel
Slot 4 request : PCM Right channel
Slot 5 request : NA
Slot 6 request : MIC channel
Slot 7 request : NA
Slot 8 request : NA
Slot 9 request : NA
Slot 10 request : NA
Slot 11 request : NA
Slot 12 request : NA
RESERVED (Filled with zero)
Description
AC97 CONTROLLER
24-7