Parameter settings, System settings – Altera V-Series Avalon-MM DMA User Manual
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Parameter Settings
3
2014.12.18
UG-01154
System Settings
Table 3-1: System Settings for PCI Express
Parameter
Value
Description
Number of Lanes
x1, x2, ×4, ×8
Specifies the maximum number of lanes supported. Avalon-
MM Interface with DMA does not support x1 configurations.
Lane Rate
Gen1 (2.5 Gbps)
Gen2 (2.5/5.0 Gbps)
Gen3 (2.5/5.0/8.0
Gbps)
Specifies the maximum data rate at which the link can operate.
Application
interface width
128-bit
256-bit
Specifies the width of the interface to the Application Layer.
The following table indicates the possible combinations.
Application
Interface Width
Configuration
Application Layer
Clock Frequency
128 bits
Gen1 x8
125 MHz
128 bits
Gen2 x4
125 MHz
128 bits
Gen2 x8
250 MHz
256 bits
Gen2 x8
125 MHz
128 bits
Gen3 x4
250 MHz
256 bits
Gen3 x4
125 MHz
256 bits
Gen3 x8
250 MHz
RX Buffer credit
allocation -
Minimum
Low
Determines the allocation of posted header credits, posted
data credits, non-posted header credits, completion header
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