CY7C4425/4205/4215
CY7C4225/4235/4245
11
Notes:
23. PAF offset = m. Number of data words written into FIFO already = 64 – m + 1 for the CY7C4425, 256 – m + 1 for the CY7C4205, 512 – m + 1 for the
CY7C4215. 1024 – m + 1 for the CY7C4225, 2048 – m + 1 for the CY7C4235, and 4096 – m + 1 for the CY7C4245.
24. PAF is offset = m.
25. 64 – m words in CY7C4425, 256 – m words inCY7C4205, 512 – m word in CY7C4215. 1024 – m words in CY7C4225, 2048 – m words in CY7C4235, and
4096 – m words in CY7C4245.
26. 64 – m + 1 words in CY7C4425, 256 – m + 1 words in CY7C4205, 512 – m +1 words in CY7C4215, 1024 – m + 1 CY7C4225, 2048 – m + 1 in CY74235,
and 4096 – m + 1 words in CY7C4245.
27. 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.
28. PAF offset = m.
29. 64 – m words in CY7C4425, 256 – m words in FIFO for CY7C4205, 512 – m word in CY7C4215. 1024 – m words in CY7C4225, 2048 – m words in CY7C4235,
and 4096 – m words in CY7C4245.
30. tSKEW3 is the minimum time between a rising RCLK and a rising WCLK edge for PAF to change state during that clock cycle. If the time between the edge of RCLK and the
rising edge of WCLK is less than tSKEW3, then PAF may not change state until the next WCLK rising edge.
Switching Waveforms (continued)
Note
tENH
WEN
WCLK
REN
RCLK
tCLKH
tPAF
tENS
tCLKL
tENS
tPAF
42X5–15
FULL
− M WORDS
IN FIFO
FULL
− M + 1 WORDS
IN FIFO
Programmable Almost Full Flag Timing
[26]
PAF
[24]
23
[25]
Note
Note
tENH
WCLK
PAF
RCLK
tCLKH
tENS
FULL
− M WORDS
IN FIFO
tCLKL
tENS
FULL-
M+1
Ω ORDS
INFIFO
42X5–16
tENH
tENS
tENH
tENS
tPAF
REN
WEN2
tSKEW3
tPAFsynch
[30]
28
27
WEN
Programmable Almost Full Flag Timing (applies only in SMODE (SMODE in LOW))
[29]