
45
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72T3645/55/65/75/85/95/105/115/125 2.5V TeraSync
36-BIT FIFO
1K x 36, 2K x 36, 4K x 36, 8K x 36, 16K x 36, 32K x 36, 64K x 36, 128K x 36 and 256K x 36
FEBRUARY 4, 2009
Figure
19.
Retransmit
from
Mark
(First
Word
Fall
Through
Mode)
tREF
tENS
tENH
5907
drw24
tENS
W
MK-1
WCLK
RCLK
REN
RT
OR
PAF
HF
PAE
Q
n
12
1
tPAFS
tREF
2
WEN
tENS
tA
tENS
W
MK
W
MK+1
tA
W
MK+n
tA
W
MK+1
W
MK+2
tA
tENS
MARK
tENH
tENS
tPAES
(6)
tA
tSKEW2
W
MK
tA
tHF
3
NOTES:
1
.
Retransmit
setup
is
complete
when
OR
returns
LOW.
2.
OE
=
LOW;
RCS
=
LOW.
3.
RT
must
be
HIGH
when
reading
from
FIFO.
4
.
Once
MARK
is
set,
the
write
pointer
will
not
increment
past
the
‘marked’
location,
preventing
overwrites
of
Retransmit
data.
5
.
Before
a
“MARK”
can
be
set
there
must
be
at
least
x
number
of
bytes
of
data
between
the
Write
Pointer
and
Read
Pointer
locati
ons.
x
=
32
for
the
IDT72T3645/72T3655/72T3665/72T3675/72T3685/72T3695,
x
=
128
for
the
IDT72T36105/72T36115,
x
=
256
for
the
IDT72T36125.
Remember,
4
(x9)
bytes
=
2
(x18)
words
=
1
(x36)
long
word.
6
.
A
transition
in
the
PAE
flag
may
occur
one
RCLK
cycle
earlier
than
shown,
(on
cycle
2).