2-16
Architecture
Lattice Semiconductor LatticeECP/EC Family Data Sheet
MULT sysDSP Element
This multiplier element implements a multiply with no addition or accumulator nodes. The two operands, A and B,
are multiplied and the result is available at the output. The user can enable the input/output and pipeline registers.
Figure 2-18 shows the MULT sysDSP element.
Figure 2-18. MULT sysDSP Element
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. A registered overflow
signal is also available. The overflow conditions are provided later in this document. Figure 2-19 shows the MAC
sysDSP element.
Figure 2-19. MAC sysDSP Element
Multiplier
x
n
m
m
n
m
n
m
n
n
m
m+n
m+n
(default)
CLK (CLK0,CLK1,CLK2,CLK3)
CE (CE0,CE1,CE2,CE3)
RST(RST0,RST1,RST2,RST3)
Pipeline
Register
Input
Register
Multiplier
Multiplicand
Signed
Shift Register A InShift Register B In
Shift Register A OutShift Register B Out
Output
Input Data
Register A
Input Data
Register B
Output
Register
To
Multiplier
Multiplier
x
n
m
m+n
(default)
m+n+16 bits
(default)
m+n+16 bits
(default)
Input Data
Register B
Input Data
Register A
m
n
n
n
m
n
n
m
Overflow
Register
Output
Register
Accumulator
Multiplier
Multiplicand
SignedAB
Shift Register A InShift Register B In
Shift Register A OutShift Register B Out
Output
Addn
Accumsload
Pipeline
Register
CLK (CLK0,CLK1,CLK2,CLK3)
CE (CE0,CE1,CE2,CE3)
RST(RST0,RST1,RST2,RST3)
Input
Register
Pipeline
Register
Input
Register
Pipeline
Register
Input
Register
Pipeline
Register
To
Accumulator
To
Accumulator
To
Accumulator
Overflow
signal
