If you turn on Use specified frequency instead of calculated frequency, the Quartus II software
assumes that the value in the Achieved memory clock frequency box is correct. If it is not, timing
analysis results are incorrect.
Note:
Related Information
•
Implementing and Parameterizing Memory IP
The Implementing and Parameterizing Memory IP
chapter in the
External Memory Interface
Handbook.
•
Functional Description Hard Memory Interface
The Functional Description--Hard Memory Interface
chapter in the
External Memory Interface
Handbook.
"EMI-Related HPS Features in SoC Devices" describes features specific to the HPS SDRAM controller.
Using the Address Span Extender Component
The FPGA-to-HPS bridge and FPGA-to-HPS SDRAM memory-mapped interfaces expose their entire 4 GB
address spaces to the FPGA fabric. The Address Span Extender component provides a memory-mapped
window into the address space that it masters. Using the address span extender, you can expose portions of
the HPS memory space without needing to expose the entire 4-GB address space.
You can use the address span extender between a soft logic master and an FPGA-to-HPS bridge or FPGA-
to-HPS SDRAM interface. This component reduces the number of address bits required for a master to
address a memory-mapped slave interface located in the HPS.
Figure 27-1: Address Span Extender Components
Two address span extender components used in a system with the HPS.
M
M
M
S
M
S
M
4 GB
4 GB
4 GB
1 GB
512 MB
512 MB
DMA
Nios II
Processor
Address Span
Extender
Address Span
Extender
S
S
FPGA-to-SDRAM
Interface
S
FPGA-to-HPS
Bridge
HPS
Qsys System
512 MB
Window
512 MB
Window
You can also use the address span extender in the HPS-to-FPGA direction, for slave interfaces in the FPGA.
In this case, the HPS-to-FPGA bridge exposes a limited, variable address space in the FPGA, which can be
paged in using the address span extender.
For example, suppose that the HPS-to-FPGA bridge has a 1 GB span, and the HPS needs to access three
independent 1 GB memories in the FPGA portion of the device. To achieve this, the HPS programs the
address span extender to access one SDRAM (1 GB) in the FPGA at a time. This technique is commonly
called paging or windowing.
Instantiating the HPS Component
Altera Corporation
cv_54027
Using the Address Span Extender Component
27-10
2013.12.30