CS61577
THEORY OF OPERATION
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).
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.
Hardware Extended
Host
Mode
Hardware
Mode
Mode
The CS61577 provides higher performance and
more features than the CS61574 including:
Control
Method
Control
Pins
Control Pins
with Parallel
Chip Select
Serial
Interface
•
•
•
Selection of 75 Ω or 120 Ω E1 output op-
tions under software or hardware control,
50 mARMS transmitter short-circuit current
limiting for E1 (per OFTEL OTR-001),
internally controlled pulse width for E1
output options,
MODE
Pin
Level
Line
Coding
<0.2 V
Floating or >(RV+)-0.2 V
2.5 V
External
Internal-
AMI, B8ZS,
or HDB3
Yes
External
AIS
Detection
Driver
Performance
Monitor
No
No
•
•
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),
Yes
No
Yes
•
•
•
Table 1. Differences Between Operating Modes
MODE
•
•
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.
EXTENDED
PIN HARDWARE HARDWARE
FUNCTION
HOST
TPOS
TNEG
RNEG
RPOS
DPM
MTIP
MRING
-
3
TPOS
TNEG
RNEG
RPOS
DPM
TDATA
TCODE
BPV
TRANSMITTER
4
6
7
RDATA
AIS
RECEIVER/DPM
Introduction to Operating Modes
11
17
18
18
23
24
25
26
27
28
MTIP
RCODE
-
MRING
-
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.
PCS
LEN0
LEN1
LEN2
RLOOP
LLOOP
TAOS
LEN0
LEN1
LEN2
RLOOP
LLOOP
TAOS
INT
SDI
CONTROL
SDO
CS
SCLK
CLKE
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-
Table 2. Pin Definitions
8
DS155PP2
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