á
XRT72L56
SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
PRELIMINARY
REV. P1.1.2
XV
terface block of the XRT72L56 for Mode 2 (Serial/Local-Timed/Frame-Slave) Operation .................. 360
Figure 160. Behavior of the Terminal Interface signals between the XRT72L56 and the Terminal Equipment
(Mode 2 Operation) ............................................................................................................................. 361
F
RAMER
O
PERATING
M
ODE
R
EGISTER
(A
DDRESS
= 0
X
00) ..................................................................... 361
Figure 161. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input In-
terface block of the XRT72L56 for Mode 3 (Serial/Local-Timed/Frame-Master) Operation ................ 362
Figure 162. Behavior of the Terminal Interface signals between the XRT72L56 and the Terminal Equipment
(E3 Mode 3 Operation) ........................................................................................................................ 363
F
RAMER
O
PERATING
M
ODE
R
EGISTER
(A
DDRESS
= 0
X
00) ..................................................................... 363
Figure 163. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input In-
terface block of the XRT72L56 for Mode 4 (Nibble-Parallel/Loop-Timed) Operation .......................... 364
Figure 164. Behavior of the Terminal Interface signals between the XRT72L56 and the Terminal Equipment
(Mode 4 Operation) ............................................................................................................................. 365
F
RAMER
O
PERATING
M
ODE
R
EGISTER
(A
DDRESS
= 0
X
00) ..................................................................... 366
Figure 165. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input In-
terface block of the XRT72L56 for Mode 5 (Nibble-Parallel/Local-Time/Frame-Slave) Operation ..... 367
Figure 166. Behavior of the Terminal Interface signals between the XRT72L56 and the Terminal Equipment
(E3 Mode 5 Operation) ........................................................................................................................ 368
F
RAMER
O
PERATING
M
ODE
R
EGISTER
(A
DDRESS
= 0
X
00) ..................................................................... 368
Figure 167. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input In-
terface block of the XRT72L56 for Mode 6 Operation ......................................................................... 369
Figure 168. Behavior of the Terminal Interface signals between the XRT72L56 and the Terminal Equipment
(E3 Mode 6 Operation) ........................................................................................................................ 370
F
RAMER
O
PERATING
M
ODE
R
EGISTER
(A
DDRESS
= 0
X
00) ..................................................................... 370
6.2.2 The Transmit Overhead Data Input Interface ........................................................................................ 370
Figure 169. Simple Illustration of the Transmit Overhead Data Input Interface block ........................ 371
T
ABLE
72: A L
ISTING
OF
THE
O
VERHEAD
BITS
WITHIN
THE
E3
FRAME
,
AND
THEIR
POTENTIAL
SOURCES
,
WITHIN
THE
XRT72L56 IC ................................................................................................................................ 372
T
ABLE
73: D
ESCRIPTION
OF
M
ETHOD
1 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
..................... 374
Figure 170. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input
Interface (Method 1) ............................................................................................................................ 375
T
ABLE
74: T
HE
R
ELATIONSHIP
BETWEEN
THE
N
UMBER
OF
R
ISING
C
LOCK
E
DGES
IN
T
X
OHC
LK
, (
SINCE
"T
X
O-
HF
RAME
"
WAS
LAST
SAMPLED
"H
IGH
")
TO
THE
E3 O
VERHEAD
B
IT
,
THAT
IS
BEING
PROCESSED
................ 376
Figure 171. Illustration of the signal that must occur between the Terminal Equipment and the XRT72L56,
in order to configure the XRT72L56 to transmit a Yellow Alarm to the remote terminal equipment ... 378
T
ABLE
75: D
ESCRIPTION
OF
M
ETHOD
1 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
..................... 379
Figure 172. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input
Interface (Method 2) ............................................................................................................................ 380
T
ABLE
76: T
HE
R
ELATIONSHIP
BETWEEN
THE
N
UMBER
OF
T
X
OHE
NABLE
PULSES
(
SINCE
THE
LAST
OCCURRENCE
OF
THE
T
X
OHF
RAME
PULSE
)
TO
THE
E3 O
VERHEAD
B
IT
,
THAT
IS
BEING
PROCESSED
BY
THE
XRT72L56 381
Figure 173. Behavior of Transmit Overhead Data Input Interface signals between the XRT72L56 and the
Terminal Equipment (for Method 2) .................................................................................................... 383
6.2.3 The Transmit E3 HDLC Controller ........................................................................................................ 383
Figure 174. LAPD Message Frame Format ....................................................................................... 384
T
ABLE
77: T
HE
LAPD M
ESSAGE
T
YPE
AND
THE
C
ORRESPONDING
VALUE
OF
THE
F
IRST
B
YTE
,
WITHIN
THE
I
NFOR
-
MATION
P
AYLOAD
.................................................................................................................................. 384
T
RANSMIT
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ..................................................... 385
T
ABLE
78: R
ELATIONSHIP
BETWEEN
T
X
LAPD M
SG
L
ENGTH
AND
THE
LAPD M
ESSAGE
S
IZE
.................. 385
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 386
T
X
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ................................................................. 386
T
RANSMIT
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ..................................................... 386
T
X
E3 LAPD S
TATUS
AND
I
NTERRUPT
R
EGISTER
(A
DDRESS
= 0
X
34) ...................................................... 387
T
X
E3 LAPD S
TATUS
AND
I
NTERRUPT
R
EGISTER
(A
DDRESS
= 0
X
34) ...................................................... 388
Figure 175. Flow Chart depicting how to use the LAPD Transmitter (LAPD Transmitter is configured to re-
transmit the LAPD Message frame repeatedly at One-Second intervals) ........................................... 389