Xilinx 7 Series User Manual page 27

Table 2-3: Attribute Setting Description (Cont'd)
Attribute Name
USE_DPORT
USE_MULT
USE_SIMD
Pattern Detector Attributes
AUTORESET_PATDET
MASK
PATTERN
SEL_MASK
7 Series DSP48E1 User Guide
UG479 (v1.10) March 27, 2018
Settings (Default)
TRUE, FALSE (FALSE)
NONE, MULTIPLY,
DYNAMIC (MULTIPLY)
ONE48, TWO24,FOUR12
(ONE48)
NO_RESET,
RESET_MATCH,
RESET_NOT_MATCH
(NO_RESET)
48-bit field (0011...11) This 48-bit value is used to mask out certain bits during a
48-bit field (00...00)
MASK, C,
ROUNDING_MODE1,
ROUNDING_MODE2
(MASK)
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Simplified DSP48E1 Slice Operation
Attribute Description
Determines whether the pre-adder and the D Port are used or
not.
Selects usage of the multiplier. Set to NONE to save power
when using only the Adder/Logic Unit.
The DYNAMIC setting indicates that the user is switching
between A*B and A:B operations on the fly and therefore needs
to get the worst-case timing of the two paths.
Selects the mode of operation for the adder/subtracter. The
attribute setting can be one 48-bit adder mode (ONE48), two 24-
bit adder mode (TWO24), or four 12-bit adder mode (FOUR12).
Selecting ONE48 mode is compatible with Virtex-6 devices
DSP48 operation and is not actually a true SIMD mode. Typical
Multiply-Add operations are supported when the mode is set to
ONE48.
When either TWO24 or FOUR12 mode is selected, the
multiplier must not be used, and USE_MULT must be set to
NONE.
Automatically resets the P Register (accumulated value or
counter value) on the next clock cycle, if a pattern detect event
has occurred on this clock cycle. The RESET_MATCH and
RESET_NOT_MATCH settings distinguish between whether
the DSP48E1 slice should cause an auto reset of the P Register
on the next cycle:
• if the pattern is matched
or
• whenever the pattern is not matched on the current cycle but
was matched on the previous clock cycle
pattern detection. When a MASK bit is set to 1, the
corresponding pattern bit is ignored. When a MASK bit is set to
0, the pattern bit is compared.
This 48-bit value is used in the pattern detector.
Selects the mask to be used for the pattern detector. The C and
MASK settings are for standard uses of the pattern detector
(counter, overflow detection, etc.). ROUNDING_MODE1 (C-
bar left shifted by 1) and ROUNDING_MODE2 (C-bar left
shifted by 2) select special masks based off of the optionally
registered C port. These rounding modes can be used to
implement convergent rounding in the DSP48E1 slice using the
pattern detector.
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