XRT79L73 Datasheet, PDF (68/71 Pages) Exar Corporation – 3 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

XRT79L73
REV. P1.0.0
PRELIMINARY
ÿþ
3 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
RECEIVE UTOPIA INTERFACE
RECEIVE UTOPIA INTERFACE
The purpose of the Receive UTOPIA Interface block is to function as either a Standard UTOPIA Level 1, 2 or 3
Interface as it outputs ATM cell data to either an ATM Layer or ATM Adaptation Layer Processor.
FIGURE 21. TIMING DIAGRAM FOR THE RECEIVE UTOPIA INTERFACE BLOCK
t53
RxUClk
RxUData[15:0]
RxUEn*
RxUPrty
RxUSoC
RxUClav
t54
t55
DATA VALID
t57
t58
t56
t59
t62
t63
TABLE 12: TIMING INFORMATION FOR THE RECEIVE UTOPIA INTERFACE BLOCK
Symbol
PARAMETER
MIN.
TYP
MAX.
UNITS
Receive UTOPIA Interface Block (See Figure 22)
t53 Delay time from rising edge of RxUClk to Data Valid at RxU-
2.7
Data[15:0]
12
ns
t54 Rx UTOPIA Read Enable setup time to rising edge of RxUClk
4
ns
t55 Delay time from rising edge of RxUClk to valid RxUPrty bit
2.9
9.8
ns
t56 Delay time from rising edge of RxUClk to valid RxUSoC bit
3.5
9.7
ns
t57 Delay time from Read Enable false to Data Bus being tri-stated
1
11.5
16
ns
t58 Delay time from Read Enable false to RxUPrty bit being tri-
stated
1
12
16
ns
66