PM7340 S/UNI-IMA-8
PRELIMINARY
INVERSE MULTIPLEXING OVER ATM
DATA SHEET
PMC-2001723
ISSUE 3
INVERSE MULTIPLEXING OVER ATM
12.3.1.2
Unchannelized
Unchannelized is used for data streams that are not either T1 or E1 framed.
When using the unchannelized interface, the user is responsible for providing a
clock which has all framing or overhead bits gapped out. The S/UNI-IMA-8
receives/sources one bit of data for each clock pulse.
The unchannelized mode allows a wider range of clock frequencies. As the
serial line frequency increases, the number of links supported decreases.
12.3.1.3
Rules for Choosing Clock frequencies
SYSCLK(min) = Max((50MHz * Line Throughput(Mbps)/130 Mbps), REFCLK)
æ
ç
ç
ç
ç
è
4 ö
3
æ
ç
è
ö
14 + NumLines *
÷
Num.Lines * Line.Clock.Freq
REFCLK(min)=max
,
6
4* Line.Clock.Period
æ
ö
4* Line.Clock.Period
REFCLK.Period
3
4
æ
ç
è
ö
Num.Linesmax ≤ ç
−14 *
÷
ç
è
Table 35
Serial
# Links
REFCLK
SYSCLK Frequency
Frequency
Frequency
1.544 Mhz
2.048 Mhz
2.304 Mhz
8
8
8
≥19.44
≥ 20 Mhz
≥20Mhz
≥20 Mhz
Mhz
≥19.44
Mhz
≥19.44
Mhz
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
260
PMC [ PMC-SIERRA, INC ]
