LFE2-20E-5FN256I Lattice, LFE2-20E-5FN256I Datasheet - Page 24

• Manufacturer Part Number: LFE2-20E-5FN256I
• Description: IC FPGA 21KLUTS 193I/O 256FPBGA
• Manufacturer: Lattice
• Series: ECP2r

Specifications of LFE2-20E-5FN256I

• Number Of Logic Elements/cells: 21000
• Number Of Labs/clbs: 2625
• Total Ram Bits: 282624
• Number Of I /o: 193
• Number Of Gates: -
• Voltage - Supply: 1.14 V ~ 1.26 V
• Mounting Type: Surface Mount
• Operating Temperature: -40°C ~ 100°C
• Package / Case: 256-BGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 220-1170; LFE2-20E-5FN256I; Q6411457

Lattice Semiconductor
If an EBR is pre-loaded during configuration, the GSR input must be disabled or the release of the GSR during
device Wake Up must occur before the release of the device I/Os becomes active.
These instructions apply to all EBR RAM and ROM implementations.
Note that there are no reset restrictions if the EBR synchronous reset is used and the EBR GSR input is disabled.
sysDSP™ Block
The LatticeECP2/M family provides a sysDSP block, making it ideally suited for low cost, high performance Digital
Signal Processing (DSP) applications. Typical functions used in these applications are Finite Impulse Response
(FIR) filters, Fast Fourier Transforms (FFT) functions, Correlators, Reed-Solomon/Turbo/Convolution encoders and
decoders. These complex signal processing functions use similar building blocks such as multiply-adders and mul-
tiply-accumulators.
sysDSP Block Approach Compared to General DSP
Conventional general-purpose DSP chips typically contain one to four (Multiply and Accumulate) MAC units with
fixed data-width multipliers; this leads to limited parallelism and limited throughput. Their throughput is increased by
higher clock speeds. The LatticeECP2/M, on the other hand, has many DSP blocks that support different data-
widths. This allows the designer to use highly parallel implementations of DSP functions. The designer can opti-
mize the DSP performance vs. area by choosing an appropriate level of parallelism. Figure 2-22 compares the fully
serial and the mixed parallel and serial implementations.
Figure 2-22. Comparison of General DSP and LatticeECP2/M Approaches
sysDSP Block Capabilities
The sysDSP block in the LatticeECP2/M 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 LatticeECP2/M 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. In the LatticeECP2/
M family the DSP elements can be concatenated.
The resources in each sysDSP block can be configured to support the following elements:
Accumulator
Multiplier
Single
Operand
Function implemented in
General purpose DSP
A
x
Operand
B
M loops
Operand
A
x
Operand
Multiplier 0
B
2-21
Multiplier 1
Operand
A
accumulate
Function implemented
x
(k adds)
m/k
in LatticeECP2/M
Operand
B
+ +
LatticeECP2/M Family Data Sheet
Output
Operand
A
x
Operand
Multiplier k
B
loops
m/k
Architecture