CDB61574 Cirrus Logic, Inc., CDB61574 Datasheet - Page 8

• Manufacturer Part Number: CDB61574
• Description: T1/e1 LINE Interface
• Manufacturer: Cirrus Logic, Inc.

THEORY OF OPERATION
CS61577 Enhancements Relative to CS61574
Existing designs using the CS61574 can be con-
verted to the higher performance, pin-compatible
CS61577 with no changes to the PCB, external
component or system software.
The CS61577 provides higher performance and
more features than the CS61574 including:
Introduction to Operating Modes
The CS61577 supports three operating modes
which are selected by the level of the MODE pin
as shown in Tables 1 and 2, Figure 7, and Figures
A1-A3 of the Applications section.
The modes are Hardware Mode, Extended Hard-
ware Mode, and Host Mode. In Hardware and
Extended Hardware Modes, discrete pins are used
to configure and monitor the device. The Ex-
tended Hardware Mode provides a parallel chip
select input which latches the control inputs al-
8
Selection of 75
tions under software or hardware control,
50 mA
limiting for E1 (per OFTEL OTR-001),
output options,
35% lower power consumption,
Increased transmitter immunity to signal re-
flections for improved signal quality,
Optional AMI, B8ZS, HDB3 encoder/de-
coder or external line coding support,
Receiver AIS (unframed all ones) detection,
Improved receiver Loss of Signal handling
(LOS set at power-up, reset upon receipt of
3 ones in 32 bit periods with no more than
15 consecutive zeros),
Transmitter TTIP and TRING outputs are
forced low when TCLK is static,
The Driver Performance Monitor operates
over a wider range of input signal levels.
internally controlled pulse width for E1
RMS
transmitter short-circuit current
or 12
E1 output op-
lowing individual ICs to be configured using a
common set of control lines. In the Host Mode,
an external processor monitors and configures the
device through a serial interface. There are thir-
teen multi-function pins whose functionality is
determined by the operating mode. (see Table 2).
RECEIVER/DPM
TRANSMITTER
Performance
FUNCTION
Detection
CONTROL
Control
Monitor
MODE
Coding
Method
Driver
Table 1. Differences Between Operating Modes
Level
Line
AIS
Pin
Hardware
Table 2. Pin Definitions
PIN HARDWARE
11
17
18
18
23
24
25
26
27
28
External
3
4
6
7
Control
<0.2 V
Mode
Pins
Yes
No
RLOOP
MRING
LLOOP
RNEG
RPOS
TPOS
TNEG
TAOS
MTIP
LEN0
LEN1
LEN2
DPM
-
Control Pins
AMI, B8ZS,
with Parallel
Chip Select
Floating or
Hardware
Extended
or HDB3
Internal-
Mode
2.5 V
Yes
No
HARDWARE
EXTENDED
RCODE
TCODE
RLOOP
LLOOP
MODE
RDATA
TDATA
TAOS
LEN0
LEN1
LEN2
BPV
PCS
AIS
-
CS61577
>(RV+)-0.2 V
Interface
External
DS155PP2
Serial
Mode
Host
Yes
MRING
No
RNEG
RPOS
HOST
TPOS
TNEG
SCLK
CLKE
MTIP
DPM
SDO
INT
SDI
CS
-