CP390
Hotswap
ID 19976, Rev. 0200
Page 4 - 4
®
PEP Modular Computers GmbH
4.1.1.3 The Hotswap Board
To ensure that a board may be removed and replaced in a working bus without
disturbing the system it requires the following additional features.
•
precharge
•
power ramping
•
hotswap Control and status register bits
•
automatic interrupt generation whenever a board is about to be removed or
replaced.
•
an LED to indicate that the board may be safely removed.
4.1.1.4 Software and Operating System
No hotswap support is currently provided by Intel based operating systems. Windows
2000, which is scheduled to become available in February 2000, is expected to provide
hotswap support. Special software will require to be developed for other proprietary
systems.
In a hotswap environment the software driver and the operating system have the
following additional requirements:
•
The OS must provide the possibility to initialize PCI devices
during normal
operation whenever required (allocate resources).
•
The OS must provide the possibility to load or unload software drivers during
normal operation whenever required.
4.2 Design Implementation on the CP390
4.2.1
Power Ramping
On the CP390, a special hotswap controller is used to ramp up the supply voltage of the
PMC modules (Back End Power). This is done to avoid transients on the 3.3V and the
5V power supplies from the Hotswap system. When the power supply is stable, the
hotswap controller generates a reset on the PMC slots to put the devices into a definite
state.
4.2.2
Precharge
Precharge is provided on the CP390 by a resistor on each signal line (PCI bus),
connected to a 1V reference voltage.
4.2.3
Handle Switch
A microswitch is situated in the extractor handle. Opening the handle initiates the
generation of the ENUM interrupt (produced by the onboard logic).
