LFE2-20E-5FN256I Lattice, LFE2-20E-5FN256I Datasheet - Page 591

• 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
Pseudo Dual Port RAM (RAM_DP) – EBR Based
The EBR blocks in LatticeECP2/M devices can be configured as Pseudo-Dual Port RAM or RAM_DP. IPexpress
allows users to generate the Verilog-HDL or VHDL along with EDIF netlists for the memory size as per design
requirements.
IPexpress generates the memory module as shown in Figure 11-15.
Figure 11-15. Pseudo Dual Port Memory Module Generated by IPexpress
The generated module makes use of these EBR blocks or primitives. For memory sizes smaller than an EBR block,
the module will be created in one EBR block. If the specified memory is larger than one EBR block, multiple EBR
blocks can be cascaded in depth or width (as required to create these sizes).
In Pseudo Dual Port RAM mode, the input data and address for the ports are registered at the input of the memory
array. The output data of the memory is optionally registered at the output.
The various ports and their definitions for the Single Port Memory are listed in Table 11-8. The table lists the corre-
sponding ports for the module generated by IPexpress and for the EBR RAM_DP primitive.
Table 11-8. EBR-based Pseudo-Dual Port Memory Port Definitions
Reset (RST) resets only the input and output registers of the RAM. It does not reset the contents of the memory.
Chip Select (CS) is a useful port when multiple cascaded EBR blocks are required by the memory. The CS signal
forms the MSB for the address when multiple EBR blocks are cascaded. Since CS is a 3-bit bus, it can cascade
eight memories easily. However, if the memory size specified by the user requires more than eight EBR blocks, the
ispLEVER software automatically generates the additional address decoding logic, which is implemented in the
PFU external to the EBR blocks.
Generated Module
Port Name in
RdClockEn
WrClockEn
RdAddress
WrAddress
RdClock
WrClock
Reset
Data
WE
—
Q
WrAddress
WrClockEn
EBR Block Primitive
WrClock
Port Name in the
Reset
Data
ADW[x2:0]
ADR[x1:0]
DO[y1:0]
WE
DI[y2:0]
CS[2:0]
CLKW
CLKR
CEW
CER
RST
WE
EBR based Pseudo
Dual Port Memory
RAM_DP
11-17
Read Clock Enable
Write Clock Enable
Read Address
Write Address
Write Enable
Description
Read Clock
Write Clock
Chip Select
Read Data
Write Data
LatticeECP2/M Memory Usage Guide
Reset
RdClock
RdClockEn
RdAddress
Q
Rising Clock Edge
Rising Clock Edge
Active State
Active High
Active High
Active High
Active High
—
—
—
—
—