lf3324 LOGIC Devices Incorporated, lf3324 Datasheet - Page 13

• Manufacturer Part Number: lf3324
• Description: 24mbit Frame Buffer / Fifo
• Manufacturer: LOGIC Devices Incorporated

Flag Outputs
DEVICES INCORPORATED
JTAG
LOGIC Devices Incorporated
PF - Programmable Almost Full
PF goes HIGH (active) when the write pointer is more than (MAX_depth - (MAX_depth x TH)) locations
ahead of the read pointer. TH is a threshold value stored in Register 9 [2:0]. PF is updated on the
rising edge of WCLK. TRS bits either entering of emerging to/from the device can be mapped to PF
(Register B[3:0]).
PE - Programmable Almost Empty Flag
PE goes HIGH (active) when the write pointer is less than or equal to (MAX_depth - (MAX_depth x TL))
locations ahead of the read pointer. TL is a threshold value stored in Register 9 [2:0]. PE is updated
on the rising edge of RCLK. TRS bits either entering of emerging to/from the device can be mapped
to PE (Register B[7:4]).
COLLIDE - Memory Read/Write Pointer Collision Flag
This flag goes high whenever the read and write addresses to the memory core coincide.
By monitoring the partial full/empty flags, the user can ascertain the direction of approach,
i.e., read pointer catching up with write (FIFO empty) or write pointer catching up with read
(FIFO full). TRS bits from D and Q can be mapped to COLLIDE (Register B[3:0]).
TDI - JTAG input data
TDI is the input data pin when using JTAG.
TDO - JTAG output data
TDO is the output data pin when using JTAG.
TRSTB - JTAG reset
TRSTB is used to reset all the registers and state machine fount the the JTAG module.
Detailed Signal Definitions
13
24Mbit Frame Buffer / FIFO
Preliminary Datasheet
Video Imaging Product
June 8, 2007 LDS.3324 G
LF3324