LFEC LATTICE [Lattice Semiconductor], LFEC Datasheet - Page 18

• Manufacturer Part Number: LFEC
• Description: LatticeECP/EC Family Data Sheet
• Manufacturer: LATTICE [Lattice Semiconductor]

Lattice Semiconductor
Figure 2-17. Comparison of General DSP and LatticeECP-DSP Approaches
sysDSP Block Capabilities
The sysDSP block in the LatticeECP-DSP family supports four functional elements in three 9, 18 and 36 data path
widths. The user selects a function element for a DSP block and then selects the width and type (signed/unsigned)
of its operands. The operands in the LatticeECP-DSP family sysDSP Blocks can be either signed or unsigned but
not mixed within a function element. Similarly, the operand widths cannot be mixed within a block.
The resources in each sysDSP block can be configured to support the following four elements:
The number of elements available in each block depends in the width selected from the three available options x9,
x18, and x36. A number of these elements are concatenated for highly parallel implementations of DSP functions.
Table 2-1 shows the capabilities of the block.
Table 2-7. Maximum Number of Elements in a Block
Some options are available in four elements. The input register in all the elements can be directly loaded or can be
loaded as shift register from previous operand registers. In addition by selecting ‘dynamic operation’ in the ‘Signed/
Unsigned’ options the operands can be switched between signed and unsigned on every cycle. Similarly by select-
ing ‘Dynamic operation’ in the ‘Add/Sub’ option the Accumulator can be switched between addition and subtraction
on every cycle.
• MULT
• MAC
• MULTADD
• MULTADDSUM (Multiply, Addition/Subtraction, Accumulate)
MULT
MAC
MULTADD
MULTADDSUM
Accumulator
Multiplier
Single
Width of Multiply
Function implemented in
Operand
General purpose DSP
A
Σ
x
Operand
B
(Multiply)
(Multiply, Accumulate)
(Multiply, Addition/Subtraction)
M loops
Operand
x9
8
4
4
2
A
x
Operand
Multiplier 0
B
2-15
Multiplier 1
Operand
A
Accumulator
Function implemented
x
Operand
in LatticeECP
B
x18
4
2
2
1
Σ
LatticeECP/EC Family Data Sheet
Output
Operand
A
x
Operand
x36
Multiplier
—
—
—
1
(k-1)
B
Architecture
loops
m/k