IDT723611 CMOS SyncFIFO
64 x 36 COMMERCIAL TEMPERATURE RANGES
5
PIN DESCRIPTION (CONTINUED)
Symbol Name I/O Description
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
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 I Odd parity is checked on each port when ODD/
EVEN
is HIGH, and even
EVEN
Select parity is checked when ODD/
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 O When any byte applied to terminals A0-A35 fails parity,
PEFA
is LOW.
Flag (Port A) Bytes are organized as A0-A8, A9-A17, 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 setup 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
A0-A35 inputs.
PEFB
Port-B Parity Error O When any byte applied to terminals B0-B35 fails parity,
PEFB
is LOW.
Flag (Port B) Bytes are organized as B0-B8, B9-B17, B18-B26, B27-B35, 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 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 setup by having
CSB
LOW, ENB HIGH, W/RB LOW,
MBB HIGH, and PGB HIGH, the
PEFB
flag is forced HIGH regardless of the
state of the B0-B35 inputs
PGA Port-A Parity I Parity is generated for mail2 register reads from port A when PGA is HIGH.
Generation The type of parity generated is selected by the state of the ODD/
EVEN
input.
Bytes are organized as A0-A8, A9-A17, A18-A26, and A27-A35. The generated parity bits are output in the most significant bit of each byte.
PGB Port-B Parity I Parity is generated for data reads from port B when PGB is HIGH. The type
Generation of parity generated is selected by the state of the ODD/
EVEN
input. Bytes are
organized as B0-B8, B9-B17, B18-B26, and B27-B35. The generated parity
bits are output in the most significant bit of each byte.
RST
Reset I To reset the device, four LOW-to-HIGH transitions of CLKA and four LOW-to-
HIGH transitions of CLKB must occur while
RST
is LOW. This sets the AF,
MBF1
, and
MBF2
flags HIGH and the EF, AE, and FF flags LOW. The LOW-
to-HIGH transition of
RST
latches the status of the FS1 and FS0 inputs to
select almost-full and almost-empty flag offset.
W/RA Port-A Write/Read I A HIGH selects a write operation and a LOW selects a read operation on
Select 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.
W/RB Port-B Write/Read I A HIGH selects a write operation and a LOW selects a read operation on
Select port B for a LOW-to-HIGH transition of CLKB. The B0-B35 outputs are in the
high-impedance state when W/RB is HIGH.