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11
COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES
IDT72V295/72V2105 3.3V HIGH DENSITY CMOS
SUPERSYNC FIFOTM 131,072 x 18, 262,144 x 18
If FWFT mode is selected, the FIFO will mark the beginning of the
Retransmit setup by setting
OR HIGH. During this period, the internal read
pointer is set to the first location of the RAM array.
When
OR goes LOW, Retransmit setup is complete; at the same time,
the contents of the first location appear on the outputs. Since FWFT mode
is selected, the first word appears on the outputs, no LOW on
REN is
necessary. Reading all subsequent words requires a LOW on
REN to
enable the rising edge of RCLK. See Figure 12, Retransmit Timing (FWFT
Mode), for the relevant timing diagram.
For either IDT Standard mode or FWFT mode, updating of the
PAE, HF
and
PAF flags begin with the rising edge of RCLK that RT is setup. PAE is
synchronized to RCLK, thus on the second rising edge of RCLK after
RT is
setup, the
PAE flag will be updated. HF is asynchronous, thus the rising
edge of RCLK that
RTis setup will update HF. PAFis synchronized to WCLK,
thus the second rising edge of WCLK that occurs tSKEW after the rising edge
of RCLK that
RT is setup will update PAF. RT is synchronized to RCLK.