4
COMMERCIAL AND INDUSTRIAL
TEMPERATURE RANGES
IDT723613 CMOS CLOCKED FIFO WITH
BUS-MATCHING AND BYTE SWAPPING 64 x 36
JANUARY 14, 2009
TEMPERATURE RANGES
Symbol Name I/O Description
A0-A35 Port A Data I/O 36-bit bidirectional data port for side A.
AE Almost-Empty Flag O Programmable Almost-Empty flag synchronized to CLKB. It is LOW when Port B the number of 36-bit
Port B words in the FIFO is less than or equal to the value in the offset register, X.
AF Almost-Full Flag O Programmable Almost-Full flag synchronized to CLKA. It is LOW when the number of 36-bit empty location
Port A in the FIFO is less than or equal to the value in the offset register, X.
B0-B35 Port B Data I/O 36-bit bidirectional data port for side B
BE Big-Endian Select I Selects the bytes on port B used during byte or word FIFO reads. A LOW on BE selects the most significant
bytes on B0-B35 for use, and a HIGH selects the least significant bytes.
CLKA Port A Clock I CLKA is a continuous clock that synchronizes all data transfers through port A and can be asynchronous or
coincident to CLKB. FF and AF are synchronized to the LOW-to-HIGH transition of CLKA.
CLKB Port B Clock I CLKB is a continuous clock that synchronizes all data transfers through port B and can be asynchronous or
coincident to CLKA. Port-B byte swapping and data port sizing operations are also synchronous to the
LOW-to-HIGH transition of CLKB. EF and AE are synchronized to the LOW-to-HIGH transition of CLKB.
CSA Port A Chip Select I CSA must be LOW to enable a LOW-to-HIGH transition of CLKA to read or write data on port A. The
A0-A35 outputs are in the high-impedance state when CSA is HIGH.
CSB Port B Chip Select I CSB must be LOW to enable a LOW-to-HIGH transition of CLKB to read or write data on port B. The
B0-B35 outputs are in the high-impedance state when CSB is HIGH.
EF Empty Flag O EF is synchronized to the LOW-to-HIGH transition of CLKB. When EF is LOW, the FIFO is empty, and
Port B reads from its memory are disabled. Data can be read from the FIFO to its output register when EF is
HIGH. EF is forced LOW when the device is reset and is set HIGH by the second LOW-to-HIGH transition
of CLKB after data is loaded into empty FIFO memory.
ENA Port A Enable I ENA must be HIGH to enable a LOW-to-HIGH transition of CLKA to read or write data on port A.
ENB Port B Enable I ENB must be HIGH to enable a LOW-to-HIGH transition of CLKB to read or write data on port B.
FF Full Flag O FF is synchronized to the LOW-to-HIGH transition of CLKA. When FF is LOW, the FIFO is full, and writes
Port A to its memory are disabled. FF is forced LOW when the device is reset and is set HIGH by the second
LOW-to-HIGH transition of CLKA after reset.
FS1, FS0 Flag Offset Selects I The LOW-to-HIGH transition of RST latches the values of FS0 and FS1, which loads one of four preset
values into the Almost-Full flag and Almost-Empty flag offsets.
MBA Port A Mailbox Select I A high level on MBA chooses a mailbox register for a port A read or write operation. When the A0-A35
outputs are active, mail2 register data is output.
MBF1 Mail1 Register Flag O 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 set LOW. MBF1 is set HIGH by a LOW-to-HIGH transition of
CLKB when a port B read is selected and both SIZ1 and SIZ0 are HIGH. MBF1 is set HIGH when the
device is reset.
MBF2 Mail2 Register Flag O 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 set 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 when the device is reset.
ODD/ Odd/Even Parity Select I Odd parity is checked on each port when ODD/EVEN is HIGH, and even parity is checked when ODD
EVEN EVEN is LOW. ODD/EVEN also selects the type of parity generated for each port if parity generation is
enabled for a read operation.
PEFA Port A Parity Error Flag O When any byte applied to terminals A
0-A35 fails parity, PEFA is LOW. Bytes are organized as A0-A8, A9-A17,
(Port A) A18-A26, and A27-A35, with the most significant bit of each byte serving as the parity bit. The type of parity
checked is determined by the state of the ODD/EVEN input. The parity trees used to check the A0-A35
inputs are shared by the mail2 register to generate parity if parity generation is selected by PGA. Therefore,
if a mail2 read with parity generation is set up by having CSA LOW, ENA HIGH, W/RA LOW, MBA HIGH
and PGA HIGH, the PEFA flag is forced HIGH regardless of the state of the A0-A35 inputs.
PEFB Port B Parity Error Flag O When any valid byte applied to terminals B0-B35 fails parity, PEFB is LOW. Bytes are organized as B0-B8,
(PortB) B9-B17, B18-B26, and B27-B35, with the most significant bit of each byte serving as the parity bit. A byte is
valid when it is used by the bus size selected for port B. The type of parity checked is determined by the
state of the ODD/EVEN input. The parity trees used to check the B0-B35 inputs are shared by the mail1
register to generate parity if parity generation is selected by PGB. Therefore, if a mail1 read with parity
generation is set up by having CSB LOW, ENB HIGH, W/RB LOW, SIZ1 and SIZ0 HIGH and PGB
HIGH, the PEFB flag is forced HIGH regardless of the state of the B0-B35 inputs.
PIN DESCRIPTION
