User manual

One Stop Systems OSS-PCIe-HIB35-x4
Page 3
1. Overview
1.a. Board Description
The switch-based is PCIe x4 cable adapter can be used in two modes; as a network adapter between two systems and as an
I/O adapter between a host system and a downstream I/O device.
1.a.1
Network adapter
The switch-based cable adapter can be configured to operate in upstream and downstream modes when cabled between
two processors. The main function of the switch-based board is to:
1) isolate the spread spectrum clock that is transmitted from both processors, and
2) allow memory transfers from one processor’s memory to the other’s memory
When used in this architecture, it is assumed that the customer is writing a specific driver for his application or using the
ExpressNet 2.0 driver installed on both systems.
1.a.2
I/O adapter
The switch-based adapter can also be used in a host system cabled to a downstream I/O device in applications where noise
from the host system must be isolated from the downstream appliance by the switch.
Note: See the factory for the availability of the ExpresssNet 2.0 driver.
Note: The clock on the switch-based adapter is set at 100.3 Mhz due to a PCIe specification requirement that states that in
order to isolate spread spectrum, the clock between the two systems must be set to higher than the anticipated jitter of the
100mhz clock. Therefore, if the application is to operate the HIB35x4 from a host system to a downstream device that emits
its own clock, a downstream HIB35x4 must also be used.