LF3304 datasheet(4/12 Pages) LODEV

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DEVICES INCORPORATED

LF3304

Dual Line Buffer/FIFO

Video Imaging Products

08/16/2000–LDS.3304-F

LDB — RAM Array B Load

When LDB is LOW, data on BIN11-0 is

latched in the LF3304 on the rising

edgeofWCLKB.

WENA — Write Enable A

If WENA is LOW, data on AIN11-0 is

written to the device on the rising edge

of WCLKA. When RAM Array A is

full, WENA is ignored.

RENA — Read Enable A

If RENA is LOW, data from RAM Array

A is read and presented on AOUT11-0

after tD has elapsed from the rising

edge of RCLKA if the output port is

enabled. If RENA goes HIGH, the last

value loaded in the RAM Array A

output register will remain unchanged.

When RAM Array A is empty, RENA is

ignored.

WENB — Write Enable B

If WENB is LOW, data on BIN11-0 is

written to the device on the rising edgle

of WCLKB. When RAM Array B is full,

WENB is ignored.

RENB — Read Enable B

If RENB is LOW, data from RAM Array

B is read and presented on BOUT11-0

after tD has elapsed from the rising

edge of RCLKB if the output port is

enabled. If RENB goes HIGH, the last

value loaded in the RAM Array B

output register will remain unchanged.

When RAM Array B is empty, RENB is

ignored.

RWA — Reset Write A

The write address pointer is reset to the

first physical location when RWA is set

LOW. After power up, the LF3304

requires a Reset Write for initialization

because the write address pointer is not

defined at that time.

RRA — Reset Read A

The read address pointer is reset to the first

physical location when RRA is set LOW.

Afterpowerup,theLF3304requiresaReset

Read for initialization because the read

address pointer is not defined at that time.

RWB — Reset Write B

See RWA Description.

RRB — Reset Read B

See RRA description.

OEA — Output Enable A

When OEA is LOW, AOUT11-0 is

enabled for output. When OEA is

HIGH, AOUT11-0 is placed in a high-

impedence state. The flag outputs are

not affected by OEA.

OEB — Output Enable B

When OEB is LOW, BOUT11-0 is

enabled for output. When OEB is

HIGH, BOUT11-0 is placed in a high-

impedence state. The flag outputs are

not affected by OEB.

Outputs

AOUT11-0 — Data Output A

AOUT11-0 is the 12-bit registered data

outputport.

BOUT11-0 — Data Output B

BOUT11-0 is the 12-bit registered data

outputport.

FFA — Full Flag A

FFA goes LOW when RAM Array A is

full of data. When FFA is LOW, RAM

Array A can not be written to. The Full

Flag is synchronized to the rising edge

ofWCLKA.

EFA — Empty Flag A

EFA goes LOW when the read pointer is

equal to the write pointer, indicating that

RAM Array A is empty. When EFA is

LOW, read operations can not be

performed. The Empty Flag is synchro-

nized to the rising edge of RCLKA.

FFB — Full Flag B

FFBgoesLOWwhenRAMArrayBisfull

ofdata. WhenFFBisLOW,RAMArrayB

can not be written to. The Full Flag is

synchronizedtotherisingedgeofWCLKB.

EFB — Empty Flag B

EFB goes LOW when the read pointer

is equal to the write pointer, indicating

that RAM Array B is empty. When EFB

is LOW, read operations can not be

performed. The Empty Flag is synchro-

nized to the rising edge of RCLKB.

PAFA—ProgrammableAlmost-FullFlagA

PAFA goes LOW when the write

pointer is (Full – N) locations ahead of

the read pointer. N is the value stored

in the PAFA register and has no default

value. PAFA is synchronized to the

rising edge of WCLKA.

PAEA—ProgrammableAlmost-EmptyFlagA

PAEA goes HIGH when the write

pointer is (N + 1) location ahead of the

read pointer. N is the value stored in

the PAEA register and has no default

value. PAEA is synchronized to the

rising edge of RCLKA.

PAFB—ProgrammableAlmost-FullFlagB

PAFB goes LOW when the write pointer

is (Full – N) locations ahead of the read

pointer. N is the value stored in the

PAFB register and has no default value.

PAFB is synchronized to the rising

edgeofWCLKB.

PAEB—ProgrammableAlmost-EmptyFlagB

PAEB goes HIGH when the write

pointer is (N + 1) location ahead of the

read pointer. N is the value stored in

the PAEB register and has no default

value. PAEB is synchronized to the

rising edge of RCLKB.

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