XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. 1.2.1
á
X
Operation) .................................................................................................................................................... 324
5.3.5.2 Nibble-Parallel Mode Operation Behavior of the XRT72L50 ....................................................... 325
Figure 139. An Illustration of the behavior of the signals between the Receive Payload Data Output Interface block of the
XRT72L50 and the Terminal Equipment ...................................................................................................... 325
Figure 140. The XRT72L50 DS3/E3 Framer IC being interfaced to the Receive Section of the Terminal Equipment (Nibble-
Parallel Mode Operation) ............................................................................................................................. 326
5.3.6 Receive Section Interrupt Processing ................................................................................................... 327
5.3.6.1 Enabling Receive Section Interrupts ........................................................................................... 327
Figure 141. Illustration of the signals that are output via the Receive Payload Data Output Interface block (for Nibble-Parallel
Mode Operation). ......................................................................................................................................... 327
5.3.6.2 Enabling/Disabling and Servicing Interrupts ................................................................................ 328
6.0 E3/ITU-T G.832 Operation of the XRT72L50 ..................................................................................... 339
6.1 D
ESCRIPTION
OF
THE
E3, ITU-T G.832 F
RAMES
AND
A
SSOCIATED
O
VERHEAD
B
YTES
........................................ 339
6.1.1 Definition of the Overhead Bytes ........................................................................................................... 339
Figure 142. Illustration of the E3, ITU-T G.832 Framing Format. ................................................................................ 339
6.1.1.1 Frame Alignment (FA1 and FA2) Bytes ...................................................................................... 340
6.1.1.2 Error Monitor (EM) Byte .............................................................................................................. 340
6.1.1.3 The Trail-Trace Buffer (TTB) Byte ............................................................................................... 340
6.1.1.4 Maintenance and Adaptation (MA) Byte ..................................................................................... 341
T
ABLE
65: D
EFINITION
OF
THE
T
RAIL
T
RACE
B
UFFER
B
YTES
,
WITHIN
T
HE
E3, ITU-T G.832 F
RAMING
F
ORMAT
................. 341
6.1.1.5 The Network Operator (NR) Byte ................................................................................................ 342
6.1.1.6 The General Purpose Communications Channel (GC) Byte ....................................................... 342
6.2 T
HE
T
RANSMIT
S
ECTION
OF
THE
XRT72L50 (E3 M
ODE
O
PERATION
) .................................................................. 342
T
ABLE
66: A L
ISTING
OF
THE
V
ARIOUS
P
AYLOAD
T
YPE
V
ALUES
AND
THEIR
CORRESPONDING
M
EANING
............................. 342
6.2.1 The Transmit Payload Data Input Interface Block ................................................................................. 343
Figure 143. The Transmit Section configured to operate in the E3 Mode ................................................................... 343
Figure 144. The Transmit Payload Data Input Interface Block .................................................................................... 344
T
ABLE
67: L
ISTING
AND
D
ESCRIPTION
OF
THE
PINS
ASSOCIATED
WITH
THE
T
RANSMIT
P
AYLOAD
D
ATA
I
NPUT
I
NTERFACE
... 344
6.2.1.1 Mode 1 - The Serial/Loop-Timing Mode ...................................................................................... 346
Figure 145. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 1(Serial/
Loop-Timed) Operation ................................................................................................................................ 346
Figure 146. Behavior of the Terminal Interface signals between the Transmit Payload Data Input Interface block of the
XRT72L50 and the Terminal Equipment (for Mode 1 Operation) ................................................................. 347
6.2.1.2 Mode 2 - The Serial/Local-Timed/Frame-Slave Mode Behavior of the XRT72L50 ..................... 348
Figure 147. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 2 (Serial/
Local-Timed/Frame-Slave) Operation .......................................................................................................... 349
6.2.1.3 Mode 3 - The Serial/Local-Timed/Frame-Master ModeBehavior of the XRT72L50 .................... 350
Figure 148. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (Mode 2
Operation) .................................................................................................................................................... 350
Figure 149. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 3 (Serial/
Local-Timed/Frame-Master) Operation ........................................................................................................ 351
6.2.1.4 Mode 4 - The Nibble-Parallel/Loop-Timed Mode Behavior of the XRT72L50 ............................. 352
Figure 150. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (E3 Mode 3
Operation) .................................................................................................................................................... 352
Figure 151. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 4 (Nibble-
Parallel/Loop-Timed) Operation ................................................................................................................... 353
Figure 152. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (Mode 4
Operation) .................................................................................................................................................... 354
6.2.1.5 Mode 5 - The Nibble-Parallel/Local-Time/Frame-Slave Interface Mode Behavior of the XRT72L50 .
355
Figure 153. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 5 (Nibble-
Parallel/Local-Timed/Frame-Slave) Operation ............................................................................................. 356
6.2.1.6 Mode 6 - The Nibble-Parallel/Local-Timed/Frame-Master Interface Mode Behavior of the XRT72L50
357
Figure 154. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (E3 Mode 5
Operation) .................................................................................................................................................... 357
Figure 155. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 6 (Nibble-
Parallel/Local-Timed/Frame-Master) Operation ........................................................................................... 358
6.2.2 The Transmit Overhead Data Input Interface ........................................................................................ 359
Figure 156. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (E3 Mode 6
Operation) .................................................................................................................................................... 359
Figure 157. The Transmit Overhead Data Input Interface block .................................................................................. 360
T
ABLE
68: A L
ISTING
OF
THE
O
VERHEAD
BITS
WITHIN
THE
E3
FRAME
,
AND
THEIR
POTENTIAL
SOURCES
,
WITHIN
THE
XRT72L50 IC