The GPV allows you to set the bridge’s issuing capabilities to support single or multiple transactions. The
GPV also lets you set a write tidemark through the
wr_tidemark
register, to control how much data is
buffered in the bridge before data is written to slaves in the FPGA fabric.
It is critical to provide correct clock settings for the lightweight HPS-to-FPGA bridge, even if your
design does not use this bridge. The
l4_mp_clk
clock is required for GPV access on the HPS-to-
FPGA and FPGA-to-HPS bridges.
Note:
Related Information
•
AXI Bridges Block Diagram and System Integration
•
on page 5-3
Lightweight HPS-to-FPGA Bridge Master Signals
All the lightweight HPS-to-FPGA bridge master signals have a fixed width. The following tables list all the
signals exposed by the lightweight HPS-to-FPGA master interface to the FPGA fabric.
Table 5-16: Lightweight HPS-to-FPGA Bridge Master Write Address Channel Signals
Description
Direction
Width
Signal
Write address ID
Output
12 bits
AWID
Write address
Output
21 bits
AWADDR
Burst length
Output
4 bits
AWLEN
Burst size
Output
3 bits
AWSIZE
Burst type
Output
2 bits
AWBURST
Lock type—Valid values are 00 (normal access) and
01 (exclusive access)
Output
2 bits
AWLOCK
Cache policy type
Output
4 bits
AWCACHE
Protection type
Output
3 bits
AWPROT
Write address channel valid
Output
1 bit
AWVALID
Write address channel ready
Input
1 bit
AWREADY
Table 5-17: Lightweight HPS-to-FPGA Bridge Master Write Data Channel Signals
Description
Direction
Width
Signal
Write ID
Output
12 bits
WID
Write data
Output
32 bits
WDATA
Write data strobes
Output
4 bits
WSTRB
Write last data identifier
Output
1 bit
WLAST
Altera Corporation
HPS-FPGA AXI Bridges
5-11
Lightweight HPS-to-FPGA Bridge Master Signals
cv_54005
2013.12.30