AK2308LV_05 Datasheet, PDF (9/31 Pages) Asahi Kasei Microsystems – SPEECH CODEC for Digital Key telephone

ASAHI KASEI
2. PCM Data Interface
[AK2308LV]
AK2308LV supports 4 PCM data interface modes.
- A/u-Law PCM data mode( Long or Short frame)
This mode is for interface of 64kbps PCM data which are compressed /extended by A -law or u-law. Both Long
frame and short frame format are acceptable. The PCM data occupies the first time slot of the PCM data bus
which is specified by the frame sync signal. Please refer to the format diagram. A -law or u-law is selectable via
CPU register.
- 16 bit Linear data Mode
This mode is for the interface the 16 bit linear PCM data. PCM CODEC of AK2308LV operates at 14 bit accuracy.
The 2 bits of the LSB are fixed in the 16 bit data stream.
- AK130 B1 Mode
This mode provides the PCM data Interface to AK130, the TCM transceiver for PBX/KTS system. PCM data format
is 64kbps A-law or u-law data. The timing between data and FS is dif ferent from the A/u-Law PCM data mode
written above. In this mode the PCM data are transmitted/received via B1 channel , one of the PCM data
channel of the AK130.
- AK130 B2 Mode
This mode provides the PCM data interface to AK130 B2 channel in th e same manner as AK130 B1 Mode.
In every mode, the digital voice data are in and out from DR and DX pin, respectively, and the bit clock and the 8KHz
frame sync signal will be fed via BCLK and FS. And FS must be 8kHz clock that is synchronized with BCLK. The order
of PCM and linear data is MSB first.
Table 2-A Summary of PCM interface modes
Mode
PCM data
BCLK rate
format
A/u-Law PCM data
mode
A/u-Law
64K x N
(N: 1 to 32)
16bit Linear data
mode
16bit
Linear
64K x N
(N: 2 to 32)
AK130 B1
A/u-Law
2.048MHz
mode
AK130 B2
A/u-Law
2.048MHz
mode
frame
signal
LF/SF
auto select
SF
only
AK130 FS
signal
AK130 FS
signal
Time
slot
1^st Time slot
first 16 bit after
FS signal
B1 channel of AK130
B2 channel of AK130
2-1. Selection of the interface mode
These four interface modes are selectable through the CPU register which specified below.
A/u-Law is also selectable from the same CPU register and it is effective in the A/u -law PCM interface mode and AK130
B1/B2 modes.
PCM Control
Register Type : Read Write[Address:0001
D2-D0:(PCM_1-0, u/A-law)]
ADD
D7
D6
D5
D4
D3
D2
D1
D0
1
-
-
-
-
-
PCM_1 PCM_0
u/A
law
Default
0
0
0
0
0
0
0
0
PCM_1、0 ； PCM interface mode select
PCM_1 PCM_0
Mode
0
0
A/u-Law PCM data mode
0
1
16bit Linear interface mode
1
0
AK130 B1 mode
1
1
AK130 B2 mode
u/A-law ; PCM compress/Extend format select
A/u-law
Compress/Extend
0
u-law
1
A-law
MS0227-E-01
9
2005/12