M28529G-12 Mindspeed Technologies, M28529G-12 Datasheet - Page 18

• Manufacturer Part Number: M28529G-12
• Description: ATM IMA 8.192Mbps 1.8V/3.3V 484-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of M28529G-12

• Package: 484BGA
• Utopia Type: Level 2
• Typical Operating Supply Voltage: 1.8|3.3 V
• Minimum Operating Supply Voltage: 1.71|3.135 V
• Maximum Operating Supply Voltage: 1.89|3.465 V
• Maximum Output Rate: 8.192 Mbps

Figure 1-3.
Since the ATM layer data rate is often less than the bandwidth available across the links in the IMA group, the IMA
engine generates IMA Filler cells when no ATM layer cells are available. (The IMA Filler cells perform the same
basic function as Idle cells in a non-IMA ATM system and are discarded by the IMA receiver.)
The IMA frame rate is intentionally set slightly below the available payload bandwidth of the IMA link. To allow for
timing differences between the links in a group, the IMA standard requires that the system insert an extra ICP cell
every 2049 cells. This cell is called the SICP cell and is inserted immediately after the normal ICP cell for that link
and results in the frame being M+1 cells long. Information in the ICP cell payload signals the insertion of these cells
so that the receiver does not lose framing and can identify and discard these cells. For further details consult the
IMA standard.
One link in each group is designated the Timing Reference Link (TRL). All timing issues for the group are relative to
this link.
28529-DSH-001-K
This cell will be in
Link 0
Link 1
Link 2
the next frame
IMA Frame; Length = 16; Number of links = 3
Incoming data from the ATM layer (which doesn't
know that the data is being split into frames)
ATM
x
ATM
36
Data output into an IMA frame
ATM
15
ATM payload;
cell x in the sequence
34
F
F
ATM
35
ATM
ATM
ATM
14
31
32
33
ATM
34
ATM
ATM
ATM
13
28
29
30
ATM
33
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ATM
ATM
ATM
12
25
26
27
ATM
32
ATM
ATM
11
23
24
F
...
ATM
ATM
10
21
22
F
ICP
Delay between the cells arrival at
n
Always at least 1 ICP cell per frame
the IMA device results in Filler
1 IMA frame
ATM
ATM
19
20
9
F
This link selected as the Timing Reference
Link, (TRL), thus first ICP starts at 0.
M = 16
IMA control Protocol Cell
IFSN = n
ATM
ATM
ATM
5
ICP
17
18
8
3
cells being inserted
ATM
ATM
ATM
ATM
4
14
15
16
7
ATM
ATM
3
13
6
®
F
F
ATM
ATM
ATM
2
ICP
11
12
5
3
ATM
ATM
ATM
10
4
8
9
ATM
1
ATM
ATM
3
F
6
7
ATM
F
0
ATM
ATM
ATM
2
3
4
5
Functional Description
ATM
Filler cell
ATM
x
1
F
F
2
This cell was in the
previous frame
ATM
ATM
ICP
0
3
0
1
500027_067
3