
xr
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
XRT72L52
REV. 1.0.1
I
TABLE OF CONTENTS
GENERAL DESCRIPTION.................................................................................................1
FEATURES
...................................................................................................................................................1
APPLICATIONS
.............................................................................................................................................1
Figure 1. Block Diagram of the XRT72L52....................................................................................................................... 1
Figure 2. Pin Out of the XRT72L52 .................................................................................................................................. 2
ORDERING INFORMATION..............................................................................................2
TABLE OF CONTENTS ..................................................................................................................................I
PIN DESCRIPTIONS..........................................................................................................3
ELECTRICAL CHARACTERISTICS................................................................................22
A
BSOLUTE
M
AXIMUMS
...............................................................................................................................22
DC E
LECTRICAL
C
HARACTERISTICS
...........................................................................................................22
AC E
LECTRICAL
C
HARACTERISTICS
...........................................................................................................22
AC E
LECTRICAL
C
HARACTERISTICS
(C
ONT
.)..............................................................................................24
1.0 Timing Diagrams ................................................................................................................................28
Figure 3. Timing Diagram for Transmit Payload Input Interface, when the XRT72L52 is operating in both the DS3 and Loop-
Timing Modes.................................................................................................................................................. 28
Figure 4. Timing Diagram for the Transmit Payload Input Interface, when the XRT72L52 is operating in both the DS3 and
Local-Timing Modes ........................................................................................................................................ 28
Figure 5. Timing Diagram for the Transmit Payload Data Input Interface, when the XRT72L52 is operating in both the DS3/
Nibble and Looped-Timing Modes................................................................................................................... 29
Figure 6. Timing Diagram for the Transmit Payload Data Input Interface, when the XRT72L52 is operating in the DS3/Nibble
and Local-Timing Modes ................................................................................................................................. 29
Figure 7. Timing Diagram for the Transmit Overhead Data Input Interface (Method 1 Access)..................................... 30
Figure 8. Timing Diagram for the Transmit Overhead Data Input Interface (Method 2 Access)..................................... 30
Figure 9. Transmit LIU Interface Timing - TxPOS and TxNEG are updated on the rising edge of TxLineClk ................ 31
Figure 10. Transmit LIU Interface Timing - TxPOS and TxNEG are updated on the falling edge of TxLineClk ............. 31
Figure 11. Receive LIU Interface timing - RxPOS and RxNEG are sampled on rising edge of RxLineClk..................... 32
Figure 12. Receive LIU Interface timing - RxPOS and RxNEG are sampled on falling edge of RxLineClk ................... 32
Figure 13. Receive Payload Data Output Interface Timing............................................................................................. 33
Figure 14. Receive Payload Data Output Interface Timing (Nibble Mode Operation).................................................... 33
Figure 15. Receive Overhead Data Output Interface Timing (Method 1 - Using RxOHClk)........................................... 34
Figure 16. Receive Overhead Data Output Interface Timing (Method 2 - Using RxOHEnable)..................................... 34
Figure 17. Microprocessor Interface Timing - Intel-type Programmed I/O Read Operation ........................................... 35
Figure 18. Microprocessor Interface Timing - Intel-type Programmed I/O Write Operation............................................ 35
Figure 19. Microprocessor Interface Timing - Motorola-type Programmed I/O Read Operation.................................... 36
Figure 20. Microprocessor Interface Timing - Motorola-type Programmed I/O Write Operation .................................... 36
Figure 21. Microprocessor Interface Timing - Reset Pulse Width................................................................................... 36
2.0 The Microprocessor Interface Block ................................................................................................37
Figure 22. Block Diagram of the Microprocessor Interface Block................................................................................... 37
2.1 T
HE
M
ICROPROCESSOR
I
NTERFACE
B
LOCK
S
IGNASL
.......................................................................................... 37
T
ABLE
1: D
ESCRIPTION
OF
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
THAT
EXHIBIT
CONSTANT
ROLES
IN
BOTH
THE
I
NTEL
AND
M
OTOROLA
M
ODES
........................................................................................................................................... 38
T
ABLE
2: D
ESCRIPTION
OF
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
-
OPERATING
IN
THE
I
NTEL
M
ODE
................................. 38
T
ABLE
3: D
ESCRIPTION
OF
THE
M
ICROPROCESSOR
I
NTERFACE
S
IGNALS
-
OPERATING
IN
THE
M
OTOROLA
M
ODE
.................. 39
2.2 I
NTERFACING
THE
XRT72L52 DS3/E3 F
RAMER
TO
THE
L
OCAL
μC/μP
VIA
THE
M
ICROPROCESSOR
I
NTERFACE
B
LOCK
39
2.2.1 Interfacing the XRT72L52 DS3/E3 Framer to the Microprocessor over an 8 bit wide bi-directional Data Bus
39
2.2.2 Data Access Modes ............................................................................................................................... 40
Figure 23. Microprocessor Interface Timing - Intel-type Programmed I/O Read Operation ........................................... 41
Figure 24. Microprocessor Interface Timing - Intel-type Programmed I/O Write Operation............................................ 42
Figure 25. Microprocessor Interface Timing - Motorola-type Programmed I/O Read Operation.................................... 43
Figure 26. Microprocessor Interface Timing - Motorola-type Programmed I/O Write Operation .................................... 44
2.3 O
N
-C
HIP
R
EGISTER
O
RGANIZATION
................................................................................................................... 44
2.3.1 Framer Register Addressing .................................................................................................................. 44
T
ABLE
4: R
EGISTER
A
DDRESSING
OF
THE
F
RAMER
P
ROGRAMMER
R
EGISTERS
.................................................................... 44
2.3.2 Framer Register Description .................................................................................................................. 48
P
ART
N
UMBER
R
EGISTER
(A
DDRESS
= 0
X
02)............................................................................................51
V
ERSION
N
UMBER
R
EGISTER
(A
DDRESS
= 0
X
03).......................................................................................52