XRT74L73 Datasheet, PDF (337/488 Pages) Exar Corporation – 3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

PRELIMINARY
XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
FIGURE 137. ILLUSTRATION ON HOW A CHANNEL OF THE RECEIVE E3 FRAMER (WITHIN THE XRT74L73 FRAMER
IC) BEING INTERFACE TO THEXRT73L00 LINE INTERFACE UNIT, WHILE OPERATING IN BIPOLAR MODE
TxSER
TxInClk
TxFrame
NIBBLEINTF
RESETB
INTB
CSB
RW
DS
AS
INTB
A[8:0]
D[7:0]
5V
RxSer
RxClk
RxFrame
RxLOS
RxOOF
RxRED
RxAIS
U1
46
43 ^TxSER
61 ^TxInClk
TxFrame
25
NIBBLEINTF
28
RESETB
13
8 ^INTB
7 ^CSB
10 ^WRB_RW
9 ^RDB_DS
6 ^ALE_AS
Rdy_Dtck
15
16 ^A0
17 ^A1
18 ^A2
19 ^A3
20 ^A4
21 ^A5
22 ^A6
23 ^A7
A8
32
33 ^D0
34 ^D1
35 ^D2
36 ^D3
37 ^D4
38 ^D5
39 ^D6
D7
27
MOTO
86
88 ^RxSer
90 ^RxClk
RxFrame
95
94 ^RxLOS
93 ^RxOOF
87 ^RxRED
RxAIS
XRT74L74
65
TxPOS
64
TxNEG
63
TxLineClk
79
DMO
78
ExtLOS
77
RLOL
69
LLOOP
70
RLOOP
68
TAOS
67
TxLEV
66
ENCODIS
71
REQB
76
RxPOS
75
RxNEG
74
RxLineClk
U2
37
TPDATA
38
TNDATA
36
TCLK
4
DMO
24
RLOS
23
RLOL
14
LLB
15
RLB
2
TAOS
1
TxLEV
21
ENCODIS
12
REQDIS
33
RPOS
32
RNEG
31
RCLK1
XRT73L00
41
TTIP
40
TRING
44
MTIP
43
MRING
1 ^R3 2
270
1 ^R4 2
270
R1
1
2
36
1 ^T1 5
R2
1
2
36
4
8
1:1
TTIP
TRING
8
RTIP
9
RRING
C1
12
0.01uF
R5
37.5
R6
37.5
1 ^T2 5
4
8
1:1
RTIP
RRING
5.3.1.2.1 AMI Decoding
AMI or Alternate Mark Inversion, means that consec-
utive "one’s" pulses (or marks) will be of opposite po-
larity with respect to each other. This line code in-
volves the use of three different amplitude levels: +1,
0, and -1. The +1 and -1 amplitude signals are used
to represent one’s (or mark) pulses and the "0" ampli-
tude pulses (or the absence of a pulse) are used to
represent zeros (or space) pulses. The general rule
for AMI is: if a given mark pulse is of positive polarity,
then the very next mark pulse will be of negative po-
larity and vice versa. This alternating-polarity rela-
tionship exists between two consecutive mark pulses,
independent of the number of zeros that exist be-
tween these two pulses. Figure 138 presents an il-
lustration of the AMI Line Code as would appear at
the RxPOS and RxNEG pins of the Framer, as well
as the output signal on the line.
338