74act2708 Fairchild Semiconductor, 74act2708 Datasheet - Page 6

• Manufacturer Part Number: 74act2708
• Description: 64 X 9 First-in, First-out Memory
• Manufacturer: Fairchild Semiconductor

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Mode 3: With FIFO Full, Shift-In is Held HIGH
in Anticipation of an Empty Location
Sequence of Operation
1. The FIFO is initially full and Shift-In goes HIGH. OR is
2. Shift-Out is pulsed HIGH, Shift-Out pulse propagates
Note: MR and FULL are HIGH; OE is LOW.
initially HIGH. Shift-Out is LOW. IR is LOW.
and the first data word is latched on the rising edge of
SO. OR falls on this edge. On the falling edge of SO,
the second data word appears after propagation delay
FIGURE 3. Modes of Operation Mode 3
6
3. Input Ready goes HIGH one fall-through time, t
4. IR returns LOW pulse width t
5. Shift-In is brought LOW to complete the shift-in process
t
LOW.
the falling edge of SO. Also, HF goes HIGH one t
after SO falls, indicating that the FIFO is no longer full.
new data in. Also, HF returns LOW pulse width t
rising, indicating the FIFO is once more full.
and maintain normal operation.
D
. New data is written into the FIFO after SO goes
IP
after rising and shifting
FT
3F
, after
after
OF