SN74V215, SN74V225, SN74V235, SN74V245

512

× 18, 1024 × 18, 2048 × 18, 4096 × 18

DSP-SYNC

 FIRST-IN, FIRST-OUT MEMORIES

SCAS636E – APRIL 2000 – REVISED SEPTEMBER 2002

22

POST OFFICE BOX 655303

WCLK

WEN

tCLKH

tCLKL

tENH

tENS

tHF

D/2 Words in FIFO,

(see Notes A and B)

tHF

HF

RCLK

tENS

REN

D – 1

2

+ 1

Words in FIFO

(see Notes A and C)

D – 1

2

+ 2

D/2 Words in FIFO,

(see Notes A and B)

D – 1

2

+ 1

NOTES: A. D = maximum FIFO depth

In FWFT mode: D = 513 for the SN74V215, 1025 for the SN74V225, 2049 for the SN74V235 and 4097 for the SN74V245

In standard mode: D = 512 for the SN74V215, 1024 for the SN74V225, 2048 for the SN74V235 and 4096 for the SN74V245

B. For standard mode

C. For FWFT mode

D. Select single-device mode by setting (FL, RXI, WXI) = (0,0,0), (0,0,1), (0,1,0), (1,0,0), (1,0,1) or (1,1,0) during reset.

D/2+1 Words in FIFO,

(see Notes A and B)

Words in FIFO

(see Notes A

and C)

Words in FIFO

(see Notes A

and C)

Figure 11. Half-Full-Flag Timing (Standard and FWFT Modes)

tCLKH

tXO

See

Note A

tENS

WCLK

WEN

WXO

NOTE A: Write to last physical location.

Figure 12. Write-Expansion-Out Timing