XC3S100E Datasheet, PDF (45/193 Pages) Xilinx, Inc – DC and Switching Characteristics

Functional Description
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Table 24 defines each port of the MULT18X18SIO primitive.
Table 24: MULT18X18SIO Embedded Multiplier Primitives Description
Signal Name
Direction
Function
A[17:0]
Input
The primary 18-bit two’s complement value for multiplication. The block multiplies by
this value asynchronously if the optional AREG and PREG registers are omitted.
When AREG and/or PREG are used, the value provided on this port is qualified by
the rising edge of CLK, subject to the appropriate register controls.
B[17:0]
Input
The second 18-bit two’s complement value for multiplication if the B_INPUT attribute
is set to DIRECT. The block multiplies by this value asynchronously if the optional
BREG and PREG registers are omitted. When BREG and/or PREG are used, the
value provided on this port is qualified by the rising edge of CLK, subject to the
appropriate register controls.
BCIN[17:0]
Input
The second 18-bit two’s complement value for multiplication if the B_INPUT attribute
is set to CASCADE. The block multiplies by this value asynchronously if the optional
BREG and PREG registers are omitted. When BREG and/or PREG are used, the
value provided on this port is qualified by the rising edge of CLK, subject to the
appropriate register controls.
P[35:0]
Output
The 36-bit two’s complement product resulting from the multiplication of the two input
values applied to the multiplier. If the optional AREG, BREG and PREG registers are
omitted, the output operates asynchronously. Use of PREG causes this output to
respond to the rising edge of CLK with the value qualified by CEP and RSTP. If PREG
is omitted, but AREG and BREG are used, this output responds to the rising edge of
CLK with the value qualified by CEA, RSTA, CEB, and RSTB. If PREG is omitted and
only one of AREG or BREG is used, this output responds to both asynchronous and
synchronous events.
BCOUT[17:0]
Output
The value being applied to the second input of the multiplier. When the optional
BREG register is omitted, this output responds asynchronously in response to
changes at the B[17:0] or BCIN[17:0] ports according to the setting of the B_INPUT
attribute. If BREG is used, this output responds to the rising edge of CLK with the
value qualified by CEB and RSTB.
CEA
Input
Clock enable qualifier for the optional AREG register. The value provided on the
A[17:0] port is captured by AREG in response to a rising edge of CLK when this
signal is High, provided that RSTA is Low.
RSTA
Input
Synchronous reset for the optional AREG register. AREG content is forced to the
value zero in response to a rising edge of CLK when this signal is High.
CEB
Input
Clock enable qualifier for the optional BREG register. The value provided on the
B[17:0] or BCIN[17:0] port is captured by BREG in response to a rising edge of CLK
when this signal is High, provided that RSTB is Low.
RSTB
Input
Synchronous reset for the optional BREG register. BREG content is forced to the
value zero in response to a rising edge of CLK when this signal is High.
CEP
Input
Clock enable qualifier for the optional PREG register. The value provided on the
output of the multiplier port is captured by PREG in response to a rising edge of CLK
when this signal is High, provided that RSTP is Low.
RSTP
Input
Synchronous reset for the optional PREG register. PREG content is forced to the
value zero in response to a rising edge of CLK when this signal is High.
Notes:
1. The control signals CLK, CEA, RSTA, CEB, RSTB, CEP, and RSTP have the option of inverted polarity.
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DS312-2 (v1.1) March 21, 2005
Advance Product Specification