lf3338 LOGIC Devices Incorporated, lf3338 Datasheet - Page 7

• Manufacturer Part Number: lf3338
• Description: 8-bit Vertical Digital Image Filter
• Manufacturer: LOGIC Devices Incorporated

DEVICES INCORPORATED
Limiting
An output limiting function is
provided for the output of the
filter. The limit registers deter-
mine the valid range of output
values when limiting is enabled
(Bit 0 in Configuration Register 2).
There are sixteen 32-bit limit
registers. RSL
which limit register is used during
the limit operation. A value of 0
on RSL
A value of 1 selects limit register 1
and so on. Each limit register
contains both an upper and lower
limit value. If the value fed to the
limiting circuitry is less than the
lower limit, the lower limit value
is passed as the filter output. If
the value fed to the limiting
circuitry is greater than the upper
limit, the upper limit value is
F
F
IGURE
IGURE
PAUSE
CF
PAUSE
CF
CLK
11-0
LD
CLK
3-0
11-0
LD
W1: Configuration Register loaded with new data on this rising clock edge.
8. C
9. C
W1: Configuration Register loaded with new data on this rising clock edge.
W2: Select Register loaded with new data on this rising clock edge.
selects limit register 0.
3-0
OEFFICIENT
ONFIGURATION AND
ADDR
determines
ADDR
1
1
CONFIGURATION REGISTER
B
ANK
COEF
L
0
S
OADING
ELECT
passed as the filter output. RSL
may be changed every clock cycle
if desired. This allows the limit
range to be changed every clock
cycle. This is useful when filtering
interleaved data. When loading
limit values into the device, the
upper limit must be greater than
the lower limit. Limit register
loading is discussed in the LF
Interface
Coefficient Banks
The coefficient banks store the
coefficients which feed into the
multipliers in the filter. There is a
separate bank for each multiplier.
Each bank can hold 256 12-bit
coefficients. The banks are loaded
using the LF Interface
bank loading is discussed in the
LF Interface
DATA
S
R
EQUENCE WITH
EGISTER
1
TM
COEF
section.
W1
TM
COEFFICIENT SET 1
L
section.
1
OADING
7
PAUSE I
TM
ADDR
. Coefficient
S
EQUENCE WITH
2
8-Bit Vertical Digital Image Filter
SELECT REGISTER
MPLEMENTATION
3-0
Configuration and Control Registers
The configuration registers deter-
mine how the LF3338 operates.
Tables 2 through 5 show the formats
of the four configuration registers.
There are three types of control
registers: round, select, and limit.
There are sixteen round registers.
Each round register is 32 bits wide.
RSL
register is used for rounding.
There are sixteen select registers.
Each select register is 5 bits wide.
RSL
register is used for the select cir-
cuitry.
There are sixteen limit registers.
Each limit register is 32 bits wide
and stores both an upper and lower
limit value. The lower limit is
stored in bits 15-0 and the upper
Video Imaging Products
PAUSE I
3-0
3-0
determines which round
determines which select
COEF
MPLEMENTATION
DATA
7
1
04/06/1999–LDS.3338-B
W2
LF3338
W1