IDT72132 Просмотр технического описания (PDF) - Integrated Device Technology
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IDT72132 Datasheet PDF : 13 Pages
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IDT72132, IDT72142
CMOS SERIAL-TO-PARALLEL FIFO 2048 x 9 AND 4096 x 9
COMMERCIAL TEMPERATURE RANGES
PIN DESCRIPTIONS
Symbol
Name
I/O
SI
Serial Input
I
RS
Reset
I
NW
SICP
R
Next Write
I
Serial Input Clock I
Read
I
FL/RT First Load/
I
Retransmit
XI
Expansion In
I
SIX
Serial Input
I
Expansion
OE
Output Enable
I
Q0–Q8 Output Data
O
FF
Full Flag
O
EF
Empty Flag
O
AEF
Almost-Empty/
O
Almost-Full Flag
XO/HF Expansion Out/
O
Half-Full Flag
D7, D8 Data Set
O
VCC
GND
Power Supply
Ground
Description
Serial data is shifted in least significant bit first. In the serial cascade mode, the Serial Input
(SI) pins are tied together and SIX plus D7, D8 determine which device stores the data.
When RS is set LOW, internal READ and WRITE pointers are set to the first location of the
RAM array. HF and FF go HIGH, and AEF, and EF go LOW. A reset is required before an initial
WRITE after power-up. R must be HIGH during an RS cycle.
To program the Serial In word width , connect NW with one of the Data Set pins (D7, D8).
Serial data is read into the serial input register on the rising edge of SICP. In both Depth and
Serial Word Width Expansion modes, all of the SICP pins are tied together.
When READ is LOW, data can be read from the RAM array sequentially, independent of SICP.
In order for READ to be active, EF must be HIGH. When the FIFO is empty (EF-LOW), the
internal READ operation is blocked and Q0-Q8 are in a high impedance condition.
This is a dual-purpose input. In the single device configuration (XI grounded), activating
retransmit (FL/RT-LOW) will set the internal READ pointer to the first location. There is no
effect on the WRITE pointer. R must be HIGH and SICP must be LOW before setting FL/RT
LOW. Retransmit is not possible in depth expansion. In the depth expansion configuration,
FL/RT grounded indicates the first activated device.
In the single device configuration, XI is grounded. In depth expansion or daisy chain
expansion, XI is connected to XO (expansion out) of the previous device.
In the Expansion mode, the SIX pin of the least significant device is tied HIGH. The SIX pin
of all other devices is connected to the D7 or D8 pin of the previous device. For single device
operation, SIX is tied HIGH.
When OE is set LOW, the parallel output buffers receive data from the RAM array. When OE
is set HIGH, parallel three state buffers inhibit data flow.
Data outputs for 9-bit wide data.
When FF goes LOW, the device is full and data must not be clocked by SICP. When FF is
HIGH, the device is not full. See the diagram on page 7 for more details.
When EF goes LOW, the device is empty and further READ operations are inhibited. When
EF is HIGH, the device is not empty.
When AEF is LOW, the device is empty to 1/8 full or 7/8 to completely full. When AEF is HIGH,
the device is greater than 1/8 full, but less than 7/8 full.
This is a dual-purpose output. In the single device configuration (XI grounded), the device is
more than half full when HF is LOW. In the depth expansion configuration (XO connected to
XI of the next device), a pulse is sent from XO to XI when the last location in the RAM array
is filled.
The appropriate Data Set pin (D7, D8 ) is connected to NW to program the Serial In data word
width. For example: D7 - NW programs a 8-bit word width, D8 - NW programs a 9-bit word
width, etc.
Single Power Supply of 5V.
Three grounds at 0V.
2752 tbl 01
STATUS FLAGS
Number of Words in FIFO
IDT72132
0
IDT72142
0
1-255
256-1024
1-511
512-2048
1025-1792
1793-2047
2049-3584
3585-4095
2048
4096
FF AEF
H
L
H
L
H
H
H
H
H
L
L
L
HF EF
H
L
H
H
H
H
L
H
L
H
L
H
2752 tbl 02
5.36
2
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