Architecture
LatticeECP2/M Family Data Sheet
Lattice Semiconductor
• MULT (Multiply)
• MAC (Multiply, Accumulate)
• MULTADDSUB (Multiply, Addition/Subtraction)
• MULTADDSUBSUM (Multiply, Addition/Subtraction, Accumulate)
The number of elements available on 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 2-7 shows the capabilities of the block.
Table 2-7. Maximum Number of Elements in a Block
Width of Multiply
x9
8
x18
4
x36
1
MULT
MAC
2
2
—
—
—
MULTADDSUB
4
2
MULTADDSUBSUM
2
1
Some options are available in four elements. The input register in all the elements can be directly loaded or can be
loaded as a shift register from previous operand registers. By selecting “dynamic operation” the following opera-
tions are possible:
• In the ‘Signed/Unsigned’ options the operands can be switched between signed and unsigned on every cycle.
• In the ‘Add/Sub’ option the Accumulator can be switched between addition and subtraction on every cycle.
• The loading of operands can switch between parallel and serial operations.
2-22
LATTICE [ LATTICE SEMICONDUCTOR ]
