Introduction
STEL-2176
66
User Manual
SLAVE MODE, QPSK - BURST TIMING: FULL BURST
NAME
TXTCLK
(1)
TXTSDATA
TXCLKEN
TXDATAENI
TXDATAENO
(2)
TXDIFFEN
(3)
(B)
(F)
(E)
(I)
(G)
(H)
(A)
(C)
(D)
(J)
(K)
User Data
Guard Time
Preamble
TXRDSLEN
TXSCRMEN
TXSYMPLS
(L)
(M)
(L)
(N)
WCP 53820.c -12/5/97
NOTES:
(1)
All input signals shown are derived from TXTCLK. Each edge is delayed from a TXTCLK edge by typically 6 to 18 nsec.
DATAENO does not depend on TXTCLK but its edges are synchronized to TXTCLK. TXTCLK itself can be turned off after
TXDATAENI goes low.
(2)
DATAENO shown at its minimum pipeline delay position. This is achieved by setting bit 6 of Block 2 Register 36
H
to zero.
Reed-Solomon cannot be used in this mode. If bit 6 is set high, allowing Reed-Solomon an additional pipeline delay of 8
Ê
bits is
inserted into the data path. This will shift both edges of DATAENO to the right by 8 cycles of TXTCLK.
(3)
If the preamble is not encoded the same as the user data, the TXDIFFEN control can be toggled in mid transmission as shown.
Otherwise, the TXDIFFEN control can be held high or low depending on encoding desired.
(A) First data bit transition on falling edge of TXTCLK (first of 14 preamble symbols). The data will be valid on the next rising edge
of TXTCLK.
(B) TXCLKEN rises on the same falling edge of TXTCLK that the data starts on. TXCLKEN is allowed to rise any time earlier than
shown.
(C) TXDATAENI rises on the first rising edge of TXTCLK (middle of the first preamble bit).
(D) DATAENO rises on the falling edge of TXTCLK (at the end of the second symbol).
(E) TXDIFFEN rises on the rising edge of TXTCLK one symbol before the first user data symbol.
(F)
User data bits change on the falling edge of TXTCLK and must be valid during the next rising edge of TXTCLK.
(G) End of user data. Note that the data is allowed to go away immediately after it is latched in by the rising of TXTCLK which
occurs in the middle of the last user data bit.
(H) TXDIFFEN goes low on rising edge of TXTCLK (last user data symbol).
(I)
TXDATAENI goes low on rising edge of TXTCLK (on the cycle of TXTCLK after the last user data bit).
(J)
TXCLKEN must stay high until any time on or after the point where DATAENO goes low.
(K) DATAENO stays high until the 13th TXSYMPLS after TXDATAENI goes low.
(L) TXRDSLEN and TXSCRMEN go high on the first rising edge of TXTCLK in the User Data.
(M) TXRDSLEN goes low on the rising edge of TXTCLK (last user data symbol).
(N) TXSCRMEN goes low on the rising edge of TXTCLK (on the cycle of TXTCLK after the last user data bit).