Xilinx 7 Series User Manual page 44

Chapter 2: DSP48E1 Description and Specifics
X-Ref Target - Figure 2-17
C (Register)
PATTERN
C Shift by 2, 00 (Mode 2)
C Shift by 1, 0 (Mode 1)
C (Register)
MASK
SEL_MASK
Notes:
1. Denotes an internal signal.
Some of the applications that can be implemented using the pattern detector are:
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If the pattern detector is not being employed, it can be used for other creative design
implementations. These include:
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A mask field can also be used to mask out certain bit locations in the pattern detector. The
pattern field and the mask field can each come from a distinct 48-bit memory cell field or
from the (registered) C input.
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SEL_PATTERN
SEL_MASK
Figure 2-17: Pattern Detector Logic
Pattern detect with optional mask
Dynamic C input pattern match with A x B
Overflow/underflow/saturation past P[46]
A:B == C and dynamic pattern match, for example, A:B OR C == 0, A:B AND C == 1
A:B {function} C == 0
48-bit counter auto reset (terminal count detection)
Detecting mid points for rounding operations
Duplicating a pin (for example, the sign bit) to reduce fanout and thus increase speed.
Implementing a built-in inverter on one bit (for example, the sign bit) without having
to route out to the fabric.
Checking for sticky bits in floating point, handling special cases, or monitoring the
DSP48E1 slice outputs.
Raising a flag if a certain condition is met or if a certain condition is no longer met.
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P
PATTERNBDETECTPAST
PATTERNDETECTPAST
PATTERN = 48'b00000000...
MASK = 48'b00111111...
P
(1)
PATTERNBDETECT
(1)
PATTERNDETECT
UG369_c1_17_051209
7 Series DSP48E1 User Guide
UG479 (v1.10) March 27, 2018