ASAHI KASEI
[AK4101A]
OPERATION OVERVIEW
n General Description
The AK4101A is a monolithic CMOS circuit that biphase-encodes and transmits audio data, auxiliary information data
and etc according to the AES3, IEC60958, S/PDIF and EIAJ CP1201 interface standards. There are four sets of stereo
channels that can be transmitted simultaneously. The chip accepts audio data and auxiliary information data separately,
multiplexes and biphase-mark encodes the data internally, and drives it directly or through a transformer to a
transmission line. There are two modes of operation: asynchronous and synchronous. See section of “Asynchronous
Mode/ Synchronous Mode”.
n Initialization
The AK4101A takes 8 bit clock cycles to initialize after PDN pin goes inactive. Also, for correct synchronization,
MCLK should be synchronized with LRCK but the phase is not critical.
n MCLK and LRCK Relationship
For correct synchronization, MCLK and LRCK should be derived from the same clock signal either directly (as through
a frequency divider) or indirectly (for example, as through a DSP). The relationship of BICK to LRCK is fixed and
should not change. If MCLK or LRCK move such that they are shifted (128fs x 3) or more cycles from their initial
conditions, the chip will reset the internal frame and bit counters. However, control registers are not initialized. The
following frequencies are supported for MCLK.
CKS1
CKS0
MCLK
128fs
256fs
384fs
512fs
fs
0
0
1
1
0
1
0
1
28k-192kHz
28k-108kHz
28k-54kHz
28k-54kHz
Table 1. MCLK Frequency
n Asynchronous Mode/ Synchronous Mode
1. Asynchronous Mode (software controlled)
The AK4101A can be configured in the asynchronous mode by connecting the ANS pin to logic “L”. In this mode the
16 to 24-bit audio samples are accepted through a configured audio serial port, and the channel status and user data
through a serial control host interface (SCI). The SCI allows access to internal buffer memory and control registers
which are used to store the channel status and user data. 4bytes per channel of user and channel status is stored. This
data is multiplexed with the audio data from the audio serial port, the parity bit is generated, and the bit stream is
biphase-mark encoded and driven through the RS422 line drivers. The CRCC code for the channel status is also
generated according to the professional mode definition in the AES3 standards. This mode also allows for software
control for mute, reset, audio format selection, clock frequency settings and output enables, via the serial host interface.
MS0250-E-00
2003/07
- 11 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
