XRT79L74 Datasheet, PDF (55/70 Pages) Exar Corporation – 4 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

PRELIMINARY
4 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
XRT79L74
REV. P1.0.0
TRANSMIT UTOPIA INTERFACE
The purpose of the Transmit UTOPIA Interface block is to function as either a Standard UTOPIA Level 1, 2 or 3
Interface as it accepts ATM cell data from either an ATM Layer or ATM Adaptation Layer Processor, and routes
this ATM cell data to the TxFIFO within the XRT79L74.
FIGURE 10. TIMING DIAGRAM FOR THE TRANSMIT UTOPIA INTERFACE BLOCK
TxUClk
TxUData[15:0]
TxUEn*
TxUPrty
TxUSoC
TxUClav
t1
t2
VALID DATA
t3
t6
t5
t8
t7
t11
t4
t12
TABLE 8: TIMING INFORMATION FOR THE TRANSMIT UTOPIA INTERFACE BLOCK
SYMBOL
PARAMETER
MIN.
t1 TxUData[15:0] to rising edge of TxUClk Setup Time
4
t2 TxUData[15:0] Hold Time from rising edge of TxUClk
1
t3 TxUTOPIA Write Enable Setup Time to rising edge of TxUClk
4
t4 TxUTOPIA Write Enable Hold Time from rising edge of TxUClk
1
t5 TxUPrty Setup Time to rising edge of TxUClk
4
t6 TxUPrty Hold Time from rising edge of TxUClk
1
t7 TxUSoC Setup Time to rising edge of TxUClk
4
t8 TxUSoC Hold Time from rising edge of TxUClk
1
t9 TxUAddr[4:0] Setup Time to rising edge of TxUClk
4
t10 TxUAddr[4:0] Hold Time from rising edge of TxUClk
1
TYP
MAX.
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
53