
STD110
5-85
SEC ASIC
FIFO_HD
High-Density Synchronous First-In First-Out Memory
Pin Descriptions
Pin Capacitance
Unit: [SL]
Name
RCK
I/O
Description
Read Clock
Read Clock input. Upon the rising edge of RCK, it begins a read operation
when REN is low, RST is high, RTM is high and EF is low.
Read Enable input. When REN is low, the read access occurs properly.
Conversely when REN is high, no read access can occur and the read port of
the FIFO_HD goes to power down mode.
REN is latched at the rising edge of RCK.
Output Enable input. The data output enable is asynchronously operated
regardless of the state of other inputs. When OEN is high, DOUT is disabled
and goes to high-impedance state.
Reset input. Upon the falling edge of RST, the reset mode is initiated. RST
resets the read and write pointer to their initial position. RST sets EF and
resets FF. RST makes DOUT[] zero.
Retransmit input. Upon the falling edge of RTM, the retransmit mode is initi-
ated, provided that RST is high. RTM resets the read pointer to its initial posi-
tion. RTM makes DOUT[] zero.
Write Clock input. Upon the rising edge of WCK, it begins a write operation
when WE is low, RST is high and FF is low.
Write Enable input. When WEN is low, a write access occurs properly. Con-
versely when WEN is high, no write access can occur and the write port of the
FIFO_HD goes to power down mode. WEN is latched at the rising edge of
WCK.
Data input bus. DI[] is latched on the rising edge of WCK. Data input is written
into the addressed location in write mode.
Empty Flag. If the memory has no data to be read, EF goes high. Valid reset
makes EF high and valid retransmit makes it low.
Full Flag. If the memory has no vacancy to write data, FF goes high. Valid
reset makes FF low.
Data output bus. Data output is valid after the rising edge of RCK while the
FIFO_HD is in read mode when OEN is low. Conversely when OEN is high,
DOUT[] goes to high-impedance state. By reset or retransmit operation.
DOUT[] goes to 0.
REN
Read Enable
OEN
Data Output
Enable
RST
Reset
RTM
Retransmit
WCK
Write Clock
WEN
Write Enable
DI
Date In
EF
Empty Flag
FF
Full Flag
DOUT
Data Out
RST
7.3
RTM
4.3
WCK
7.7
RCK
4.8
OEN
3.5
WEN
2.2
REN
1.3
DI/DOUT
1.2/6.2