LF3320
DEVICES INCORPORATED
Horizontal Digital Image Filter
CENB — Coefficient Address Enable B
When CENB is LOW, data on CAB
7-0
is latched into Coefficient Address
Register B on the rising edge of CLK.
When CENB is HIGH, data on CAB
7-0
is not latched and the register’s
contents will not be changed.
TXFRA — Filter A LIFO Transfer
Control
TXFRA is used to change which LIFO
in the data reversal circuitry sends
data to the reverse data path and
which LIFO receives data from the
forward data path in Filter A. When
TXFRA goes LOW, the LIFO sending
data to the reverse data path becomes
the LIFO receiving data from the
forward data path, and the LIFO
receiving data from the forward data
path becomes the LIFO sending data to
the reverse data path. The device must
see a HIGH to LOW transition of
TXFRA in order to switch LIFOs.
TXFRA is latched on the rising edge of
CLK.
TXFRB — Filter B LIFO Transfer
Control
TXFRB is used to change which LIFO
in the data reversal circuitry sends
data to the reverse data path and
which LIFO receives data from the
forward data path in Filter B. When
TXFRB goes LOW, the LIFO sending
data to the reverse data path becomes
the LIFO receiving data from the
forward data path, and the LIFO
receiving data from the forward data
path becomes the LIFO sending data to
the reverse data path. The device must
see a HIGH to LOW transition of
TXFRB in order to switch LIFOs.
TXFRB is latched on the rising edge of
CLK.
ACCA — Accumulator A Control
When ACCA is HIGH, Accumulator A
is enabled for accumulation and the
Accumulator A Output Register is
disabled for loading. When ACCA is
LOW, no accumulation is performed
and the Accumulator A Output Register
is enabled for loading. ACCA is latched
on the rising edge of CLK.
ACCB — Accumulator B Control
When ACCB is HIGH, Accumulator B
is enabled for accumulation and the
Accumulator B Output Register is
disabled for loading. When ACCB is
LOW, no accumulation is performed
and the Accumulator B Output Regis-
ter is enabled for loading. ACCB is
latched on the rising edge of CLK.
SHENA — Filter A Shift Enable
In Dual Filter Mode, SHENA enables
or disables the loading of data into the
Input (DIN
11-0
) and Filter A I/D
Registers. When SHENA is LOW, data
is latched into the Input/Cascade
Registers and shifted through the I/D
Registers on the rising edge of CLK.
When SHENA is HIGH, data can not
be loaded into the Input/Cascade
Registers or shifted through the I/D
Registers and their contents will not be
changed.
In Single Filter Mode, SHENA also
enables or disables the loading of data
into the Reverse Cascade Input (RIN
11-
0
), Cascade Output (COUT
11-0
), Reverse
Cascade Output (ROUT
11-0
) and Filter B
I/D Registers. It is important to note
that in Single Filter Mode, both SHENA
and SHENB should be connected
together. Both must be active to enable
data loading in Single Filter Mode.
SHENA is latched on the rising edge of
CLK.
SHENB — Filter B Shift Enable
In Dual Filter Mode, SHENB enables or
disables the loading of data into the
Reverse Cascade Input (RIN
11-0
),
Cascade Output (COUT
11-0
), Reverse
Cascade Output (ROUT
3-0
) and Filter B
I/D Registers. When SHENB is LOW,
data is latched into the Cascade Regis-
ters and shifted through the I/D
ROUT
11-0
— Reverse Cascade Output
In Single Filter Mode, ROUT
11-0
is a
12-bit registered cascade output port.
ROUT
11-0
on one device should be
connected to RIN
11-0
of another LF3320.
In Dual Filter Mode, ROUT
3-0
is a 4-bit
registered output port for the upper four
bits of the 16-bit Filter B output. In this
mode, ROUT
11-4
is disabled.
Controls
LDA — Coefficient A Load
When LDA is LOW, data on CFA
11-0
is
latched into the Filter A LF Interface
TM
on the rising edge of CLK. When LDA is
HIGH, data is not loaded into the Filter
A LF Interface
TM
. When enabling the LF
Interface
TM
for data input, a HIGH to
LOW transition of LDA is required in
order for the input circuitry to function
properly. Therefore, LDA must be set
HIGH immediately after power up to
ensure proper operation of the input
circuitry (see the LF Interface
TM
section
for a full discussion).
CENA — Coefficient Address Enable A
When CENA is LOW, data on CAA
7-0
is latched into Coefficient Address
Register A on the rising edge of CLK.
When CENA is HIGH, data on CAA
7-0
is not latched and the register’s
contents will not be changed.
LDB — Coefficient B Load
When LDB is LOW, data on CFB
11-0
is
latched into the Filter B LF Interface
TM
on the rising edge of CLK. When LDB is
HIGH, data is not loaded into the Filter
B LF Interface
TM
. When enabling the LF
Interface
TM
for data input, a HIGH to
LOW transition of LDB is required in
order for the input circuitry to function
properly. Therefore, LDB must be set
HIGH immediately after power up to
ensure proper operation of the input
circuitry (see the LF Interface
TM
section
for a full discussion).
Video Imaging Products
2-4
08/16/2000–LDS.3320-N
LOGIC [ LOGIC DEVICES INCORPORATED ]
