IDT723624 Datasheet, PDF (5/35 Pages) Integrated Device Technology – CMOS SyncBiFIFOTM WITH BUS-MATCHING

IDT723624/723634/723644 CMOS SyncBiFIFO™ WITH BUS-MATCHING
256 x 36 x 2, 512 x 36 x 2, 1,024 x 36 x 2
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTIONS (CONTINUED)
Symbol
Name I/O
FS1/SEN FlagOffset
I
Select 1/
Serial Enable,
FS0/SD FlagOffset
I
Select 0/
Serial Data
MBA Port A Mailbox I
Select
MBB Port B Mailbox I
Select
MBF1 Mail1Register O
Flag
MBF2 Mail2Register O
Flag
MRS1 FIFO1 Master I
Reset
MRS2 FIFO2 Master I
Reset
PRS1 FIFO1 Partial I
Reset
PRS2 FIFO2 Partial I
Reset
SIZE⁽¹⁾ Bus Size Select I
SPM⁽¹⁾
W/RA
W/RB
Serial Program- I
ming Mode
Port-A Write/
I
Read Select
Port-B Write/
I
Read Select
Description
FS1/SEN and FS0/SD are dual-purpose inputs used for flag offset register programming. During Master Reset,
FS1/SEN and FS0/SD, together with SPM, select the flag offset programming method. Three offset register
programming methods are available: automatically load one of three preset values (8, 16, or 64), parallel load
from Port A, and serial load.
When serial load is selected for flag offset register programming, FS1/SEN is used as an enable synchronous to
the LOW-to-HIGH transition of CLKA. When FS1/SEN is LOW, a rising edge on CLKA load the bit present on
FS0/SD into the X and Y registers. The number of bit writes required to program the offset registers is 32 for the
723624, 36 for the 723634, and 40 for the 723644. The first bit write stores the Y1 register MSB and the last bit
write stores the X2 register LSB.
A HIGH level on MBA chooses a mailbox register for a Port A read or write operation. When the A0-A35
outputs are active, a HIGH level on MBA selects data from the mail2 register for output and a LOW level selects
FIFO2 output register data for output.
A HIGH level on MBB chooses a mailbox register for a Port B read or write operation. When the B0-B35
outputs are active, a HIGH level on MBB selects data from the mail1 register for output and a LOW level selects
FIFO1 output register data for output.
MBF1 is set LOW by a LOW-to-HIGH transition of CLKA that writes data to the mail1 register. Writes to the
mail1 register are inhibited while MBF1 is LOW. MBF1 is set HIGH by a LOW-to-HIGH transition of CLKB when
a Port B read is selected and MBB is HIGH. MBF1 is set HIGH following either a Master or Partial Reset of
FIFO1.
MBF2 is set LOW by a LOW-to-HIGH transition of CLKB that writes data to the mail2 register. Writes to the
mail2 register are inhibited while MBF2 is LOW. MBF2 is set HIGH by a LOW-to-HIGH transition of CLKA when a
Port A read is selected and MBA is HIGH. MBF2 is set HIGH following either a Master or Partial Reset of
FIFO2.
A LOW on this pin initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B
output register to all zeroes. A LOW-to-HIGH transition on MRS1 selects the programming method (serial or parallel)
and one of three programmable flag default offsets for FIFO1 and FIFO2. It also configures Port B for bus size and
endian arrangement. Four LOW-to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKB must occur
while MRS1 is LOW.
A LOW on this pin initializes the FIFO2 read and write pointers to the first location of memory and sets the Port A
output register to all zeroes. A LOW-to-HIGH transition on MRS2 toggled simultaneously with MRS1, selects the
programming method (serial or parallel) and one of the programmable flag default offsets for FIFO2. Four LOW-
to-HIGH transitions of CLKA and four LOW-to-HIGH transitions of CLKB must occur while MRS2 is LOW.
A LOW on this pin initializes the FIFO1 read and write pointers to the first location of memory and sets the Port B
output register to all zeroes. During Partial Reset, the currently selected bus size, endian arrangement, program
ming method (serial or parallel), and programmable flag settings are all retained.
A LOW on this pin initializes the FIFO2 read and write pointers to the first location of memory and sets the Port A
output register to all zeroes. During Partial Reset, the currently selected bus size, endian arrangement, program
ming method (serial or parallel), and programmable flag settings are all retained.
A HIGH on this pin when BM is HIGH selects byte bus (9-bit) size on Port B. A LOW on this pin when BM is
HIGH selects word (18-bit) bus size. SIZE works with BM and BE to select the bus size and endian arrangement
for Port B. The level of SIZE must be static throughout device operation.
A LOW on this pin selects serial programming of partial flag offsets. A HIGH on this pin selects parallel
programming or default offsets (8, 16, or 64).
A HIGH selects a write operation and a LOW selects a read operation on Port A for a LOW-to- HIGH transition of
CLKA. The A0-A35 outputs are in the HIGH impedance state when W/RA is HIGH.
A LOW selects a write operation and a HIGH selects a read operation on Port B for a LOW-to-HIGH transition of
CLKB. The B0-B35 outputs are in the HIGH impedance state when W/RB is LOW.
NOTE:
1. BM, SIZE and SPM are not TTL compatible. These inputs should be tied to GND or VCC.
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