XP2 Datasheet, PDF (24/92 Pages) Lattice Semiconductor – LatticeXP2 Family Data Sheet

Lattice Semiconductor
Architecture
LatticeXP2 Family Data Sheet
MAC sysDSP Element
In this case, the two operands, A and B, are multiplied and the result is added with the previous accumulated value.
This accumulated value is available at the output. The user can enable the input and pipeline registers but the out-
put register is always enabled. The output register is used to store the accumulated value. The Accumulators in the
DSP blocks in LatticeXP2 family can be initialized dynamically. A registered overflow signal is also available. The
overflow conditions are provided later in this document. Figure 2-21 shows the MAC sysDSP element.
Figure 2-21. MAC sysDSP
Serial Register B in
Serial Register A in
Preload
Multiplicand
Multiplier
Signed A
Signed B
Addn
Accumsload
m
m
n
n
n
m
Input Data m
Register A
Input Data
Register B
n
Input
Register
Input
Register
Input
Register
Input
Register
n
n
Pipeline
Register
Pipeline
Register
Pipeline
Register
Pipeline
Register
SROB
SROA
Accumulator
Multiplier
x m+n
(default)
Pipeline
Register
m+n+16
(default)
m+n+16
(default)
Output
To Accumulator
To Accumulator
To Accumulator
To Accumulator
Overflow
signal
CLK (CLK0,CLK1,CLK2,CLK3)
CE (CE0,CE1,CE2,CE3)
RST(RST0,RST1,RST2,RST3)
2-21