LFE2M50E-PS-EVN Lattice, LFE2M50E-PS-EVN Datasheet - Page 48

• Manufacturer Part Number: LFE2M50E-PS-EVN
• Description: Programmable Logic IC Development Tools LatticeECP2M PCI Express Dev Kit
• Manufacturer: Lattice

Specifications of LFE2M50E-PS-EVN

• Rohs: yes
• Tool Is For Evaluation Of: LatticeECP2M-50
• Factory Pack Quantity: 1

Running the PCI Express Throughput Demo
LatticeECP2M PCI Express Development Kit User’s Guide
Table 10: Run Test Page Feature Descriptions
Feature
TLP Size
Num TLPs
Information Description
The TLP size controls allows you to select the size of the
TLPs to be sent from the SFIF. The maximum size of the
TLP will be dependent on the root complex. In MRd
mode, the maximum TLP size is limited by Max Read
Request size (512 bytes). In MWr mode, the maximum
TLP size is limited by Max TLP Size (128 bytes).
In Read/Write mode the following sizes are available for
MRd TLP and MWr TLP combinations.
This control allows the user to select the ratio of read
requests to write TLPs.
512,128 – 512-byte read requests with 128-byte
write TLPs
256,128 – 256-byte read requests with 128-byte
write TLPs
128,128 – 128-byte read requests with 128-byte
write TLPs
64,64 – 64-byte read requests with 64-byte write
TLP
32,32 – 32-byte read requests with 32-byte write
TLPs
16,16 – 16-byte read requests with 16-byte write
TLPs
1Rd,1Wr – This ratio results in one Read Request
and 1 Write TLP back-to-back. The completion data
will need to be received before another Read
Request can be made.
1Rd,4Wr – This ratio results in one Read Request
and four Write TLPs. The completion data must be
received before another Read Request can be
made. This results in much greater bandwidth since
read requests are four times the size of a write TLP.
This ratio balances the PCI Express link, but still
waits for read data.
4Rd,16Wr – This ratio results in four Read Requests
and 16 Write TLPs. This ratio allows for four read
requests to be outstanding (TAGs). This ratio is only
recommended on server class motherboards due to
the high bandwidth required. With four reads
outstanding the root complex can better utilize the
read data.
16Rd,64Wr – This ratio results in 16 Read Requests
and 64 Write TLPs. This ratio allows for 16 read
requests to be outstanding (TAGs). This ratio is only
recommended on server class motherboards due to
the high bandwidth required. With 16 read
outstanding the root complex can better utilize the
read data.
Running the Throughput Demo
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