4
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT72V3640/50/60/70/80/90 3.3V HIGH DENSITY SUPERSYNC IITM 36-BIT FIFO
1,024 x 36, 2,048 x 36, 4,096 x 36, 8,192 x 36, 16,384 x 36 and 32,768 x 36
OCTOBER 22, 2008
Figure 1. Single Device Configuration Signal Flow Diagram
words written to the FIFO do require a LOW on
REN for access. The state of
the FWFT/SI input during Master Reset determines the timing mode in use.
For applications requiring more data storage capacity than a single FIFO
canprovide,theFWFTtimingmodepermitsdepthexpansionbychainingFIFOs
in series (i.e. the data outputs of one FIFO are connected to the corresponding
data inputs of the next). No external logic is required.
These FIFOs have five flag pins,
EF/OR (Empty Flag or Output Ready),
FF/IR (Full Flag or Input Ready), HF (Half-full Flag), PAE (Programmable
Almost-Emptyflag)and
PAF(ProgrammableAlmost-Fullflag). TheEFandFF
functions are selected in IDT Standard mode. The
IR and OR functions are
selected in FWFT mode.
HF, PAE and PAF are always available for use,
irrespective of timing mode.
PAE and PAFcanbeprogrammedindependentlytoswitchatanypointin
memory. Programmableoffsetsdeterminetheflagswitchingthresholdandcan
beloadedbytwomethods:parallelorserial. Eightdefaultoffsetsettingsarealso
provided, so that
PAEcanbesettoswitchatapredefinednumberoflocations
from the empty boundary and the
PAF threshold can also be set at similar
predefinedvaluesfromthefullboundary. Thedefaultoffsetvaluesaresetduring
Master Reset by the state of the FSEL0, FSEL1, and
LD pins.
For serial programming,
SEN together with LD on each rising edge of
WCLK,areusedtoloadtheoffsetregistersviatheSerialInput(SI). Forparallel
programming,
WEN togetherwithLD oneachrisingedgeofWCLK,areused
to load the offset registers via Dn.
REN together with LD on each rising edge
ofRCLKcanbeusedtoreadtheoffsetsinparallelfromQnregardlessofwhether
serial or parallel offset loading has been selected.
During Master Reset (
MRS)thefollowingeventsoccur: thereadandwrite
pointers are set to the first location of the FIFO. The FWFT pin selects IDT
Standard mode or FWFT mode.
The Partial Reset (
PRS) also sets the read and write pointers to the first
location of the memory. However, the timing mode, programmable flag
programmingmethod,anddefaultorprogrammedoffsetsettingsexistingbefore
PartialResetremainunchanged.Theflagsareupdatedaccordingtothetiming
modeandoffsetsineffect.
PRSisusefulforresettingadeviceinmid-operation,
when reprogramming programmable flags would be undesirable.
Itisalsopossibletoselectthetimingmodeofthe
PAE(ProgrammableAlmost-
Empty flag) and
PAF (Programmable Almost-Full flag) outputs. The timing
modes can be set to be either asynchronous or synchronous for the
PAEand
PAFflags.
(x36, x18, x9) DATA OUT (Q0 - Qn)
(x36, x18, x9) DATA IN (D0 - Dn)
MASTER RESET (MRS)
READ CLOCK (RCLK/RD*)
READ ENABLE (REN)
OUTPUT ENABLE (OE)
EMPTY FLAG/OUTPUT READY (EF/OR)
PROGRAMMABLE ALMOST-EMPTY (PAE)
WRITE CLOCK (WCLK/WR*)
WRITE ENABLE (WEN)
LOAD (LD)
FULL FLAG/INPUT READY (FF/IR)
PROGRAMMABLE ALMOST-FULL (PAF)
IDT
72V3640
72V3650
72V3660
72V3670
72V3680
72V3690
PARTIAL RESET (PRS)
FIRST WORD FALL THROUGH/
SERIAL INPUT (FWFT/SI)
RETRANSMIT (RT)
4667 drw03
HALF-FULL FLAG (HF)
SERIAL ENABLE(SEN)
INPUT WIDTH (IW)
OUTPUT WIDTH (OW)
BIG-ENDIAN/LITTLE-ENDIAN (BE)
INTERSPERSED/
NON-INTERSPERSED PARITY (IP)
BUS-
MATCHING
(BM)