XRT7250 Datasheet, PDF (295/463 Pages) Exar Corporation – DS3/E3 FRAMER IC

XRT7250
DS3/E3 FRAMER IC
REV. 1.1.1
áç
FIGURE 120. APPROACH TO INTERFACING THE XRT7250 FRAMER IC DEVICE TO THE XRT7300 DS3/E3/STS-1 LIU
TxS E R
TxInC l k
TxFrame
NIB B LE INTF
RE S E TB
IN TB
CS B
RW
DS
AS
IN TB
A [8:0]
D [7:0]
5V
RxS er
RxC lk
R xFrame
R xLOS
R xO OF
RxR E D
RxA IS
U1
46
43
TxS E R
61 ^TxInClk
TxFrame
25
NIB B LE INTF
28
RE S E TB
13
8 ^INTB
7 ^{CS B}
10 ^{W R B _RW}
9 ^{RD B _DS}
6 ^{A LE _A S}
R dy _D tck
15
16 ^{A 0}
17 ^{A 1}
18 ^{A 2}
19 ^{A 3}
20 ^{A 4}
21 ^{A 5}
22 ^{A 6}
23 ^{A 7}
A8
32
33 ^D0
34 ^D1
35 ^D2
36 ^D3
37 ^D4
38 ^D5
39 ^D6
D7
27
MO TO
86
88 ^{RxS er}
90 ^{RxC lk}
R xFrame
95
94 ^RxLOS
93 ^RxOOF
87 ^{RxR E D}
RxA IS
X R T7250
65
TxP OS
64
TxN E G
63
TxLi neC l k
79
D MO
78
E xtLOS
77
R LO L
69
LLO OP
70
R LO OP
68
TA OS
67
TxLE V
66
E N CODIS
71
RE QB
76
RxP OS
75
RxNE G
74
R xLi neC l k
U2
37
TP D A TA
38
TND A TA
36
TC LK
4
D MO
24
R LO S
23
R LO L
14
LLB
15
R LB
2
TA OS
1
TxLE V
21
E N CODIS
12
RE QDIS
33
RP OS
32
RNEG
31
RC LK 1
X R T7300
41
TTIP
40
TR IN G
44
MTIP
43
MR ING
1
R3 2
270
1
R4 2
270
R1
1
2
36
1 T1
5
R2
1
2
36
4
8
1:1
TTIP
TR IN G
8
R TIP
9
RR ING
C1
1
2
0.01uF
R5
37.5
R6
37.5
1 T2
5
4
8
1:1
R TIP
RR ING
The Transmit Section of the XRT7250 contains a
block which is known as the Transmit E3 LIU Interface
block. The purpose of the Transmit E3 LIU Interface
block is to take the outbound E3 data stream, from
the Transmit E3 Framer block, and to do the following:
1. Encode this data into one of the following line
codes
a. Unipolar (e.g., Single-Rail)
b. AMI (Alternate Mark Inversion)
c. HDB3 (High Density Bipolar - 3)
2. And to transmit this data to the LIU IC.
Figure 121 presents a simple illustration of the Trans-
mit E3 LIU Interface block.
276