LF3321
Horizontal Digital Image Filter
DEVICES INCORPORATED
Improved Performance
FEATURES
111 MHz Data Rate
12-bit Data or Coefficients (Expandable to 24-bit)
32-Tap FIR Filter, Cascadable for More Filter Taps
LF Interface™ Allows All 256 Coefficient Sets to be
Updated Within Vertical Blanking
Over 49 K-bits of on-board Memory
Various Operating Modes: Dual Filter, Single Filter,
Double Wide Data or Coefficient, Matrix Multiplica-
tion, and Accumulator Access.
Selectable 16-bit Data Output with User-Defined
Rounding and Limiting
Supports Interleaved Data Streams
Supports Decimation up to 16:1 for Increas-
ing Number of Filter Taps
3.3 Volt Power Supply
144 Lead PQFP
DESCRIPTION
The LF3321 is an improved version of the LF3320 Horizontal Digital Image Filter capable of operating at
speeds of up to 111MHz. This improved speed increases flexibility and performance and enables the user
to utilize this device in more applications. For example, four interleaved data streams of 27MHz can now
be processed within one device. The part is functionally identical to the LF3320 with the exception that the
filter data path is specified to operate faster than the LF Control Interface. When operating the filter at
speeds in excess of 90MHz, loading of coefficients via the LF Interface must be throttled to a maximum
of 90MHz by asserting the PAUSE pin as required to allow sufficient setup time for the configuration data
provided to the chip via the LF Interface.
Figure 1. Switching Waveforms: LF Interface
TM
CLK
tS0
LDA
LDB
PAUSEA
PAUSEB
CFA 11-0
CFB 11-0
tCFH
tCFS
ADDRESS
CF0
CF1
tPS
tPWH
tPWL
tLH
tCYC
tPH
Figure 1 demonstrates the switching waveforms, while the switching characteristics are given in Table
1. The LF3321 filters digital images in the horizontal dimension at real-time video rates. The input and
coefficient data are both 12 bits and in two’s complement format. The output is also in two’s complement
format and may be rounded to 16 bits.
The LF3321 is designed to take advantage of symmetric coefficient sets. When symmetric coefficient sets
are used, the device can be configured as a single 32-tap FIR filter or as two separate 16-tap FIR filters.
When asymmetric coefficient sets are used, the device can be configured as a single 16-tap FIR filter or as
two separate 8-tap FIR filters. Multiple LF3321s can be cascaded to create larger filters.
Interleave/Decimation Registers (I/D Registers) allow interleaved data to be fed directly into the device and
filtered without separating the data into individual data streams.
The LF3321 can handle a maximum of sixteen data sets interleaved together. The I/D Registers and
on-chip accumulators facilitate using decimation to increase the number of filter taps. Decimation of up
to 16:1 is supported.
The LF3321 contains enough on-board memory to store 256 coefficient sets. Two separate LF Interfaces
TM
allow all 256 coefficient sets to be updated within vertical blanking.
LOGIC Devices Incorporated
1
Video Imaging Products
Feb 5, 2003 LDS.3321-A
LOGIC [ LOGIC DEVICES INCORPORATED ]
