Switching Waveforms (continued)
Programmable Almost Full Flag Timing
tCLKH
tCLKL
WCLK
WEN1
tENS tENH
WEN2
(if applicable)
PAF
tENS tENH
FULL − (M+1)WORDS
IN FIFO
RCLK
REN1,
REN2
Note 22
CY7C4261V/CY7C4271V
CY7C4281V/CY7C4291V
Note 23
tPAF
(FULL −M) WORDS
IN FIFO [24]
tSKEW2 [25]
tENS
tENS tENH
tPAF
Write Programmable Registers
tCLKH
tCLK
tCLKL
WCLK
WEN2/LD
tENS
tENH
WEN1
tENS
tDS
tDH
D0 –D8
PAE OFFSET
LSB
PAE OFFSET
MSB
PAF OFFSET
LSB
PAF OFFSET
MSB
Notes:
22. If a write is performed on this rising edge of the write clock, there will be Full − (m−1) words of the FIFO when PAF goes LOW.
23. PAF offset = m.
24. 16K − m words for CY7C4261V, 32K – m words for CY7C4271V, 64K − m words for CY7C4281V, and 128K − m words for CY4291V.
25. tSKEW2 is the minimum time between a rising RCLK edge and a rising WCLK edge for PAF to change during that clock cycle. If the time between the rising edge of RCLK
and the rising edge of WCLK is less than tSKEW2, then PAF may not change state until the next WCLK.
Document #: 38-06013 Rev. *A
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