System Controller Card
The PEX 8311 bridge, with its Root Complex mode
support, simplified generic local bus interface, PCIe
protocol packet conversion, and multiple DMA
controllers allows users to use the device as a “north
bridge” type application in embedded systems. Such
controllers often manage “control path” data. The local
bus has the capability to support numerous simultaneous
local bus devices. Figure 2 shows the bridge interfacing
a local processor, FPGA, and memory to a downstream
PCIe port. The PCIe port connects to a switching fabric
or I/O card.
to a PCIe switch. The bridge is fully interoperable with
PCIe switches from a variety of PCIe products including
multiple switches from PLX Technology with lane
counts from 8 to 32. Figure 4 illustrates PEX 8311
bridging programmable logic devices to the PEX 8524
switch. One of the many applications for the bridge is to
interface inputs via an FPGA from industrial signals
from the manufacturing floor to a PCIe switch where the
data is sent to a local processor and then to a central host
for system control applications. This use can be
generalized to many similar bridging operations such as
in instrumentation or medical imaging.
FPGA
FPGA
250MB/s
PEX 8311
PEX 8311
CPU
CPU
SDRAM
SDRAM
EEPROM
EEPROM
SRAM/
SRAM/
FPGA
FPGA
DSP
DSP
Proprietary
Proprietary
ASIC
ASIC
Local
Based
Local
Based
CPU
CPU
FPGA
FPGA
250MB/s
PEX 8311
PEX 8311
PEX
PEX 8524
PEX 8524
8524
PEX 8311
PEX 8311
To Host
Generic Local Bus
Generic Local Bus
FPGA
FPGA
PCI Express
PCI Express
250MB/s
PEX 8311
PEX 8311
Figure 2. “Northbridge” Host Bridge
Line Card Application
The number and variety of PCI Express native-mode
devices is growing quickly. As these devices become
mainstream, it will be necessary to create multifunction
and multi-port adapter cards with PCI Express
capability.
The PEX 8311 can be used to create a communications
line card that bridges a local processing device and
memory to an upstream PCIe port. The bridge allows a
line card to be a backplane or a motherboard. Figure 3
shows the PEX 8311 in this application. In this mode,
the bridge acts in an “EndPoint mode”. Configuration to
the bridge comes from the PCIe. Use of DMA for data
path and higher priority simultaneous Direct
Master/Slave for control path data is invaluable.
COM 1
COM 2
COM N
FPGA
FPGA
250MB/s
PEX 8311
PEX 8311
Figure 4. Industrial Control
In this type application, the bridge’s x1 lane PCIe 2.5 Gbps
bandwidth in combination with its large local bus capacitive
loading can support up to five simultaneous input sources on
each PEX 8311. With a Local Bus of up to 66 MHz and
32-bit data, complete bandwidth matching with the PCIe
port can be achieved in unidirectional designs.
Video Surveillance System
The PEX 8311 is a very economical bridge and can
support many “mass market” applications. These
applications include PC television capture cards, data
acquisition boards, video editing, and surveillance
systems. The later is shown in Figure 5 below. This
design allows multiple camera sources to feed their
inputs through a series of compression, buffering stages
and local processing and be bridged to a PCIe switch or
directly to a PCIe slot on a motherboard. The PC then
allows security personnel to monitor multiple feeds and
switch interactively among the various feeds. Video
editing by consumers could use a similar design
topology as well.
Camera
Camera
JPEG
JPEG
CPU
CPU
NPU
NPU
ASIC
ASIC
SRAM
SRAM
Flash
Flash
Local Bus: 66
32-bit
Local Bus: 66 MHz,
MHz, 32-bit
EEPROM
PEX
8311
PEX
8311
x1 PCIe
x1 PCIe
FIFO
FIFO
FPGA
FPGA
PEX 8311
PEX 8311
Camera
PEX 8524
PEX 8524
Figure 3. Communications Line Card
Industrial Control Systems
The PEX 8311 is an excellent choice to bridge
programmable logic, local processors, and other devices
Camera
Camera
JPEG
JPEG
CPU
CPU
FIFO
FIFO
FPGA
FPGA
PEX
8311
PEX
8311
M
o
t
h
e
r
b
o
a
r
d
Camera
Figure 5. Video Surveillance System
PLX [ PLX TECHNOLOGY ]
