Achronix Speedster22i User Macro Guide - Manual (Page 190)

Multipliers BMACC56
Speedster22i Macro Cell Library Achronix Semiconductor Proprietary PAGE 173
BMACC56 Pins
Table 7-2: BMACC56 Pin Description
Name Type Description
a[27:0] input
Data Input A. Data Input A is a 28-bit two’s complement signed
input, where bit 27 is the most significant bit. In subtraction mode,
Data Input A is the minuend.
b[27:0] input
Data Input B. Data Input B is a 28-bit two’s complement signed
input, where bit 27 is the most significant bit. In subtraction mode,
Data Input B is the subtrahend.
sub input
Subtract. Setting the subtract input to one inverts the b input so
that an a[27:0] - b[27:0] subtraction operation can be performed.
Note that the cin input also has to be set to one during a subtract
operation.
cin input Carry In. Carry input to the adder/subtractor.
mask_adda input
Adda Mask. Setting mask_adda high clears the adda input and
allows the add/sub block to pass the addb + cin value to the add/
sub output. Setting mask_adda low enables the adda input to the
add/sub block to be driven by either the dout output
(sel_cascade_in = 1’b0) or the cascade_input from the previous
BMACC56 block (sel_cascade_in = 1’b1).
ce_a input
Data Input A Input Register Clock Enable (active-high). Setting
ce_a to one allows Data Input A to be clocked into the input register
when the rst_a signal is one.
ce_b input
Data Input B Input Register Clock Enable (active-high). Setting
ce_b to one allows Data Input B to be clocked into the input register
when the rst_b signal is one.
ce_sub input
Subtract Input Register Clock Enable (active-high). Setting
ce_sub to one allows the sub input to be clocked into the input reg-
ister when the rst_sub signal is one.
ce_cin input
Carry In Input Register Clock Enable (active-high). Setting ce_cin
to one allows the cin input to be clock into the cin input register.
Setting ce_cind to zero allows the cin input register to hold its value
at the next active edge of the clock.
ce_mask_adda input
Adda Mask Input Register Clock Enable (active-high). Setting
ce_mask_adda to one allows the mask_adda input to be clocked
into the input register. Setting ce_mask_adda to zero allows the
mask input register to hold its value at the next active edge of the
clock.
ce_dout input
Data Out Output Register Clock Enable (active-high). Setting
ce_dout to one allows dout to be clocked into the Data Out Output
Register and cout to be clocked into the Carry Out Output Register.
Setting ce_dout to zero allows the Data Out Output Register to hold
its value at the next active edge of the clock.
rst_a input
Data Input A Register Reset (active-low). Asserting input rst_a per-
forms a synchronous reset of the Data Input a register upon the next
active edge of the clock, and will set the register to the value defined
by the rst_value_a parameter.