Apparatus for live bus insertion of add-on devices
Assignee3Com Corporation
InventorMichael H. Bowman
Life of this patent
Estimating the term…
Abstract
An apparatus for allowing an add-on device to be inserted onto an active bus and configurable within one bus cycle is provided. The apparatus includes passive circuits used with a sequential multi-length pin arrangement on an I/O module. The apparatus also decouples the source of power to the I/O module from other devices on the bus which limits the disruption of power during the insertion. The I/O module limits current drawn from a backplane containing the bus which may disrupt signals during the insertion of the add-on device. And finally, the I/O module also limits bus signal disruption during insertion by precharging signal pins, increasing the resistance between the add-on I/O module pins and the backplane and adding capacitance to the bus.
Claims5
An apparatus for connecting at least two devices to a plurality of bus slots on a live bus comprising:
- a power supply generating at least one supply voltage;
- a primary power line coupled to the power supply for supplying power to the at least two devices;
- one or more signal lines connected to each bus slot for transferring signals between the at least two devices;
- a device removal warning line connected to each bus slot, the device removal warning line forming a device removal signal when a device is removed from a bus slot, the device removal signal being communicated to the other devices on the bus;
- and
- an input-output module at each bus slot for connecting a device to the respective bus slot, the input-output module including
- a first primary power line pin for connecting the device to the primary power line,
- a second set of pins for connecting the device to the one or more signal lines, and
- an early warning connection pin having a length shorter than the first primary power line pin and the second set of pins so that the early warning connection pin disengages first from the device as the device is removed from the bus slot, disengagement of the early warning connection pin causing the formation of the device removal signal by the device removal warning line.
An input-output module for connecting a device to a bus slot on a live bus having a plurality of bus slots comprising:
- a first primary power line pin for connecting the device to a primary power line;
- a second set of pins for transferring signals between the device and other devices connected to the bus through one or more signal lines;
- and
- an early warning connection pin connecting the device to a device removal warning line, the early warning connection pin having a length shorter than the first primary power line pin and the second set of pins so that the early warning connection pin disengages first from the device as the device is removed from the bus slot disengagement of the early warning connection pin causing the device removal warning line to form a device removal signal which is sent to the other devices connected to the bus.
Dependencies are inferred from the claim text.