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XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
PRELIMINARY
REV. P1.1.3
I
TABLE OF CONTENTS
GENERAL DESCRIPTION ............................................................................................... 1
FEATURES
................................................................................................................................................. 1
APPLICATIONS
........................................................................................................................................... 1
Figure 1. Block Diagram of the XRT72L50 ............................................................................................ 1
Figure 2. Pin Out of the XRT72L50 ........................................................................................................ 2
ORDERING INFORMATION ............................................................................................ 2
PIN DESCRIPTIONS ........................................................................................................ 3
ELECTRICAL CHARACTERISTICS .............................................................................. 20
A
BSOLUTE
M
AXIMUMS
............................................................................................................................. 20
DC E
LECTRICAL
C
HARACTERISTICS
......................................................................................................... 20
AC E
LECTRICAL
C
HARACTERISTICS
......................................................................................................... 20
AC E
LECTRICAL
C
HARACTERISTICS
(C
ONT
.) ............................................................................................ 22
1.0 Timing Diagrams ................................................................................................................................. 26
Figure 3. Timing Diagram for Transmit Payload Input Interface, when the XRT72L50 Device is operating in
both the DS3 and Loop-Timing Modes ................................................................................................. 26
Figure 4. Timing Diagram for the Transmit Payload Input Interface, when the XRT72L50 Device is operating
in both the DS3 and Local-Timing Modes ............................................................................................. 26
Figure 5. Timing Diagram for the Transmit Payload Data Input Interface, when the XRT72L50 Device is
operating in both the DS3/Nibble and Looped-Timing Modes .............................................................. 27
Figure 6. Timing Diagram for the Transmit Payload Data Input Interface, when the XRT72L50 Device is
operating in the DS3/Nibble and Local-Timing Modes .......................................................................... 27
Figure 7. Timing Diagram for the Transmit Overhead Data Input Interface (Method 1 Access) .......... 28
Figure 8. Timing Diagram for the Transmit Overhead Data Input Interface (Method 2 Access) .......... 28
Figure 9. Transmit LIU Interface Timing - Framer is configured to update "TxPOS" and "TxNEG" on the
rising edge of "TxLineClk" ..................................................................................................................... 29
Figure 10. Transmit LIU Interface Timing - Framer is configured to update "TxPOS" and "TxNEG" on the
falling edge of "TxLineClk" .................................................................................................................... 29
Figure 11. Receive LIU Interface Timing - Framer is configured to sample "RxPOS" and "RxNEG" on the
rising edge of "RxLineClk" ..................................................................................................................... 30
Figure 12. Receiver LIU Interface Timing - Framer is configured to sample "RxPOS" and "RxNEG" on the
falling edge of "RxLineClk" .................................................................................................................... 30
Figure 13. Receive Payload Data Output Interface Timing .................................................................. 31
Figure 14. Receive Payload Data Output Interface Timing (Nibble Mode Operation) ......................... 31
Figure 15. Receive Overhead Data Output Interface Timing (Method 1 - Using RxOHClk) ................ 32
Figure 16. Receive Overhead Data Output Interface Timing (Method 2 - Using RxOHEnable) .......... 32
Figure 17. Microprocessor Interface Timing - Intel Type Programmed I/O Read Operations .............. 33
Figure 18. Microprocessor Interface Timing - Intel Type Programmed I/O Write Operations .............. 33
Figure 19. Microprocessor Interface Timing - Intel Type Read Burst Access Operation ..................... 34
Figure 20. Microprocessor Interface Timing - Intel type Write Burst Access Operation ....................... 34
Figure 21. Microprocessor Interface Timing - Motorola Type Programmed I/O Read Operation ........ 35
Figure 22. Microprocessor Interface Timing - Motorola Type Programmed I/O Write Operation ......... 35
Figure 23. Microprocessor Interface Timing - Reset Pulse Width ........................................................ 36
2.0 The Microprocessor Interface Block ................................................................................................. 37
Figure 24. Simple Block Diagram of the Microprocessor Interface Block, within the Framer IC .......... 37
2.1 T
HE
M
ICROPROCESSOR
I
NTERFACE
B
LOCK
S
IGNAL
.............................................................................................. 37
T
ABLE
1: D
ESCRIPTION
OF
THE
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
THAT
EXHIBIT
CONSTANT
ROLES
IN
BOTH
THE
I
NTEL
AND
M
OTOROLA
M
ODES
.......................................................................................................... 38
T
ABLE
2: P
IN
D
ESCRIPTION
OF
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
- W
HILE
THE
M
ICROPROCESSOR
I
NTER
-
FACE
IS
O
PERATING
IN
THE
I
NTEL
M
ODE
.................................................................................................. 38
T
ABLE
3: P
IN
D
ESCRIPTION
OF
THE
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
WHILE
THE
M
ICROPROCESSOR
I
N
-
TERFACE
IS
OPERATING
IN
THE
M
OTOROLA
M
ODE
.................................................................................... 39
2.2 I
NTERFACING
THE
XRT72L50 DS3/E3 F
RAMER
TO
THE
L
OCAL
μC/μP
VIA
THE
M
ICROPROCESSOR
I
NTERFACE
B
LOCK