ACS406CS Semtech Corporation, ACS406CS Datasheet - Page 9

• Manufacturer Part Number: ACS406CS
• Description: Two-chip Fiber Optic Modem Ics / ACS4060 100-pin Tqfp, ACS9010 44-pin TQFP
• Manufacturer: Semtech Corporation

In order to set the device for four E1 channels with a
common TCLK clock then set DR5 = DR4 = DR1 =
1; DR3 = DR2 = 0, together with a crystal of
32.768MHz as shown in the Table 15.
In order to set the device for four T1 channels with a
common TCLK clock then set DR5 = DR4 = 1; DR3
= DR2 = DR1 = 0;
30.88MHz as shown in the Table 16.
In order to set the device for four E1 channels with
an independent TCLK clock for each channel then
set DR4 = DR3 = DR2 = DR1 = 1; DR5 = 0; together
with a crystal of 32.786MHz as shown in the Table
17.
In order to set the device for four T1 channels with a
an independent TCLK clock for each channel then
set DR5 = DR4 = 1; DR3 = DR2 = DR1 = 0; together
with a crystal of 30.88MHz as shown in the Table
18.
4 * E1 Channel Selection in TX1 mode
4 * T1 Channel Selection in TX1 mode
4 * E1 Channel Selection in TX4 mode
4 * T1 Channel Selection in TX4 mode
DR5
DR5
DR5
DR5
1
1
0
0
crystal = 32.768 MHz
crystal = 30.88 MHz
crystal = 32.768 MHz
crystal = 30.88 MHz
DR4
DR4
DR4
DR4
1
1
1
1
DR3
DR3
DR3
DR3
0
0
1
1
DR2
DR2
DR2
DR2
0
0
1
1
together with a crystal of
DR1
DR1
DR1
DR1
1
0
1
0
XTAL
Divide
XTAL
Divide
XTAL
Divide
XTAL
Divide
16
20
16
20
Table 15
Table 16
Table 17
Table 18
TCLK
(MHz)
TCLK
(MHz)
TCLK
(MHz)
TCLK
(MHz)
2.048
1.544
2.048
1.544
9
Other standard frequencies may be obtained by
setting the appropriate DR(5:1) combination with a
32.768MHz crystal as shown in the Table 19.
In order to propagate asynchronous data through
the ACS406CS, the device should be configured with
CKC = 0 so that the device produces a TCLK output
clock. The TCLK clock asynchronously over-samples
the data applied to TPOS at the rate defined by
DR(5:1). The choice of TCLK frequency defines
the sample rate of the input data and therefore the
sampling-jitter appearing at RPOS of the far-end
modem.
Example:
8 - asynchronous 115kbps channels.
XTAL
DR5/4/3/2/1
CKC
TCLK clock
TPOS/TNEG data rate
Over-sample factor
Sampling Jitter (approx.')
Similar considerations apply to the maintenance
channel, which
asynchronous data.
There are up to four support channels on the
ACS406CS: TmD1/RmD1, TmD2/RmD2 TmD3/
RmD3 and TmD4/RmD4. For the purpose of this
specification these will be referred to collectively as
TmD and RmD.
The number of support channels and the bandwidth
available is dependent on the setting of the DR(5:1)
input pins.
The support channels can be used in one of two
ways selected by the input Frame. When Frame = 1,
then the support channels are said to be in Frame
Mode. When Frame = 0, then the support channels
are in maintenance mode.
Other Transmission Data Rate
Asynchronous Communication
Support channels
DR5 DR4 DR3 DR2 DR1
1
1
1
1
1
1
crystal = 32.768 MHz
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
may also be used to convey
1
0
1
0
1
0
Nos. of
Chann.
4
4
8
8
8
8
=
=
=
=
=
=
=
ACS406CS Issue 1.6 January 1999.
XTAL
Divide
32
64
32
64
128
256
Table 19
32.768MHz
1/0/1/0/1
0
1.024MHz
8.9
11%.
115kbps
TCLK
(KHz)
1024
512
1024
512
256
128