L3 Master Interface
FPGA Slave Interface
Bridge Property
32 transactions
32 transactions
Total acceptance
The FPGA-to-HPS bridge contains a GPV, described in
The Global Programmers View
. The GPV registers
provide settings that adjust the bridge slave properties when the FPGA slave interface is configured to be 32
or 128 bits wide. The slave issuing capability can be adjusted, through the
fn_mod
register, to allow one or
multiple transactions to be outstanding in the HPS. The slave bypass merge feature can also be enabled,
through the
bypass_merge
bit in the
fn_mod2
register. This feature ensures that the upsizing and
downsizing logic does not alter any transactions when the FPGA slave interface is configured to be 32 or
128 bits wide.
It is critical to provide the correct
l4_mp_clk
clock to support access to the GPV, as described in
GPV Clocks
.
Note:
Related Information
•
on page 5-3
•
on page 5-14
FPGA-to-HPS Access to ACP
When the error correction code (ECC) option is enabled in the level 2 (L2) cache controller, all accesses
from the FPGA-to-HPS bridge to the ACP must be 64 bits wide and aligned on 8-byte boundaries after up-
or downsizing takes place.
Table 5-3: FPGA Master and FPGA-to-HPS Bridge Configurations
The following table lists some possible master and FPGA-to-HPS bridge slave configurations that support accesses
to the L2 cache with ECC enabled.
FPGA-to-HPS Bridge
Slave Width
Soft Logic Master Burst
Length
Soft Logic Master Burst
Size (Width)
Soft Logic Master
Alignment
Soft Logic Master
Width
32 bits
2, 4, 6, 8, 10, 12, 14, or
16 beats
4 bytes
8 bytes
32 bits
32 bits
1 to 16 beats
8 bytes
8 bytes
64 bits
32 bits
1 to 16 beats
8 or 16 bytes
8 or 16 bytes
128 bits
64 bits
2, 4, 6, 8, 10, 12, 14, or
16 beats
4 bytes
8 bytes
32 bits
64 bits
1 to 16 beats
8 bytes
8 bytes
64 bits
64 bits
1 to 16 beats
8 or 16 bytes
8 or 16 bytes
128 bits
128 bits
2, 4, 6, 8, 10, 12, 14, or
16 beats
4 bytes
8 bytes
32 bits
128 bits
1 to 16 beats
8 bytes
8 bytes
64 bits
128 bits
1 to 16 beats
8 or 16 bytes
8 or 16 bytes
128 bits
HPS-FPGA AXI Bridges
Altera Corporation
cv_54005
FPGA-to-HPS Access to ACP
5-4
2013.12.30