lf3321qc9 LOGIC Devices Incorporated, lf3321qc9 Datasheet - Page 6

• Manufacturer Part Number: lf3321qc9
• Description: Horizontal Digital Image Filter
• Manufacturer: LOGIC Devices Incorporated

DEVICES INCORPORATED
Data Reversal
Continued
LOGIC Devices Incorporated
Functional Description
When data reversal is enabled, the circuitry uses a pair of LIFOs to reverse the order of the data sent
to the reverse data path. TXFRA and TXFRB control the LIFOs in Filters A and B respectively. When
TXFRA/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 TXFRA/TXFR B in order to switch LIFOs. If decimating by
N, TXFRA/TXFRB should go LOW once every N clock cycles. When data reversal is disabled, the circuitry
functions like an I/D Register. When feeding interleaved data through the filter, data reversal should be
disabled. Bit 6 of Configuration Register 1 and Configuration Register 3 enables or disables data reversal
for Filters A and B respectively.
Figure 7 .Filter A and Filter B Round/Limit/Select Circuitry
FILTER B RSL
RSLB
4
3-0
32
32
5
DATA OUT
DATA IN
SELECT
32
32
16
16
6
LIMIT
RND
DATA OUT
DATA IN
SELECT
32
32
16
16
LIMIT
RND
Horizontal Digital Image Filter
32
32
5
Improved Performance
Video Imaging Products
RSLA
4
FILTER A RSL
3-0
Feb 5, 2003 LDS.3321-A
LF3321