The HPS-to-FPGA bridge is mastered by the level 3 (L3) main switch and the lightweight HPS-to-FPGA
bridge is mastered by the L3 slave peripheral switch.
The FPGA-to-HPS bridge masters the L3 main switch, allowing any master implemented in the FPGA fabric
to access most slaves in the HPS. For example, the FPGA-to-HPS bridge can access the accelerator coherency
port (ACP) of the Cortex-A9 MPU subsystem to perform cache-coherent accesses to the SDRAM subsystem.
All three bridges contain global programmers view (GPV) registers. The GPV registers control the behavior
of the bridge. Access to the GPV registers of all three bridges is provided through the lightweight HPS-to-
FPGA bridge.
Related Information
•
on page 5-13
•
on page 4-1
For more information about connectivity, such as which masters have access to each bridge, refer to the
Interconnect chapter in the Cyclone V Device Handbook.
Functional Description of the AXI Bridges
The Global Programmers View
The HPS-to-FPGA bridge includes a set of registers called the GPV. The GPV provides settings to control
the bridge properties and behavior. Access to the GPV registers of all three bridges is provided through the
lightweight HPS-to-FPGA bridge.
The GPV registers can only be accessed by secure masters in the HPS or the FPGA fabric.
FPGA-to-HPS Bridge
The FPGA-to-HPS bridge provides access to the peripherals and memory in the HPS. This access is available
to any master implemented in the FPGA fabric. You can configure the bridge slave, which is exposed to the
FPGA fabric, to support 32-, 64-, or 128-bit data. The master interface of the bridge, connected to the L3
interconnect, has a data width of 64 bits.
Table 5-2: FPGA-to-HPS Bridge Properties
The following table lists the properties includes the configurable slave interface exposed to the FPGA fabric.
L3 Master Interface
FPGA Slave Interface
Bridge Property
64 bits
32, 64, or 128 bits
Data width
(2)
l3_main_clk
f2h_axi_clk
Clock domain
32 bits
32 bits
Byte address width
8 bits
8 bits
ID width
16 transactions
16 transactions
Read acceptance
16 transactions
16 transactions
Write acceptance
(2)
The bridge slave data width is user-configurable at the time you instantiate the HPS component in your system.
Altera Corporation
HPS-FPGA AXI Bridges
5-3
Functional Description of the AXI Bridges
cv_54005
2013.12.30