Abstract:
An example embodiment of a computer system that includes a removable agent that can be removed or installed without powering down the system includes a fixed bus agent and the replaceable bus agent. The fixed bus agent and the replaceable bus agent are electrically coupled together by a presence detect signal, a synchronization signal, and a data bus. A deassertion of the presence detect signal indicates to the fixed bus agent that the removable bus agent has been disconnected and is no longer electrically coupled to the fixed bus agent. The fixed bus agent then tri-states its outputs and also prevents potentially invalid data from being delivered to the core circuitry of the fixed bus agent. An assertion of the presence detect signal indicates to the fixed bus agent that the replaceable bus agent is electrically connected to the fixed bus agent. In response to the assertion of the presence detect signal, the fixed bus agent and the replaceable bus agent enter reset periods. Following the reset periods and when each bus agent is ready to communicate to the other agent, the fixed bus agent and the replaceable bus agent signal to each other over the synchronization signal that each is ready to begin communication over the data bus.
Abstract:
An example embodiment of a computer system that includes a removable agent that can be removed or installed without powering down the system includes a fixed bus agent and the replaceable bus agent. The fixed bus agent and the replaceable bus agent are electrically coupled together by a presence detect signal, a synchronization signal, and a data bus. A deassertion of the presence detect signal indicates to the fixed bus agent that the removable bus agent has been disconnected and is no longer electrically coupled to the fixed bus agent. The fixed bus agent tri-states its outputs and also prevents potentially invalid data from being delivered to the core circuitry of the fixed bus agent. An assertion of the presence detect signal indicates to the fixed bus agent that the replaceable bus agent is electrically connected to the fixed bus agent. In response to the assertion of the presence detect signal, the fixed bus agent and the replaceable bus agent enter reset periods. Following the reset periods and when each bus agent is ready to communicate to the other agent, the fixed bus agent and the replaceable bus agent signal to each other over the synchronization signal that each is ready to begin communication over the data bus.
Abstract:
An example embodiment of a computer system that includes a removable agent that can be removed or installed without powering down the system includes a fixed bus agent and the replaceable bus agent. The fixed bus agent and the replaceable bus agent are electrically coupled together by a presence detect signal, a synchronization signal, and a data bus. A deassertion of the presence detect signal indicates to the fixed bus agent that the removable bus agent has been disconnected and is no longer electrically coupled to the fixed bus agent. The fixed bus agent then tri-states its outputs and also prevents potentially invalid data from being delivered to the core circuitry of the fixed bus agent. An assertion of the presence detect signal indicates to the fixed bus agent that the replaceable bus agent is electrically connected to the fixed bus agent. In response to the assertion of the presence detect signal, the fixed bus agent and the replaceable bus agent enter reset periods. Following the reset periods and when each bus agent is ready to communicate to the other agent, the fixed bus agent and the replaceable bus agent signal to each other over the synchronization signal that each is ready to begin communication over the data bus.
Abstract:
An integrated circuit 301 has an internal transmission line 315 which receives a signal from an external transmission line 305. No termination circuitry is used to terminate the external transmission line. The internal transmission line transmits the signal passively to two or more different circuits 331, 332 on the integrated circuit. The internal transmission line may be terminated 318 at the opposite end to the external transmission line. The impedance of the internal transmission line may be matched to that of the external line. The internal transmission line may be connected to the circuits using buffers. Two transmission lines may be used to transmit differential signals.
Abstract:
An example embodiment of a computer system that includes a removable agent that can be removed or installed without powering down the system includes a fixed bus agent and the replaceable bus agent. The fixed bus agent and the replaceable bus agent are electrically coupled together by a presence detect signal, a synchronization signal, and a data bus. A deassertion of the presence detect signal indicates to the fixed bus agent that the removable bus agent has been disconnected and is no longer electrically coupled to the fixed bus agent. The fixed bus agent then tri-states its outputs and also prevents potentially invalid data from being delivered to the core circuitry of the fixed bus agent. An assertion of the presence detect signal indicates to the fixed bus agent that the replaceable bus agent is electrically connected to the fixed bus agent. In response to the assertion of the presence detect signal, the fixed bus agent and the replaceable bus agent enter reset periods. Following the reset periods and when each bus agent is ready to communicate to the other agent, the fixed bus agent and the replaceable bus agent signal to each other over the synchronization signal that each is ready to begin communication over the data bus.
Abstract:
For one disclosed embodiment, an integrated circuit may comprise an internal transmission line in one or more layers of the integrated circuit. The internal transmission line may be coupled to receive a signal from an external transmission line at a first end of the internal transmission line without use of termination circuitry. The internal transmission line may transmit the signal passively to a second end of the internal transmission line. The integrated circuit may also comprise first circuitry having an input coupled to the internal transmission line at a first location of the internal transmission line to receive the signal and second circuitry having an input coupled to the internal transmission line at a second location of the internal transmission line to receive the signal. The second location may be different from the first location. Other embodiments are also disclosed.
Abstract:
For one disclosed embodiment, an integrated circuit may comprise an internal transmission line in one or more layers of the integrated circuit. The internal transmission line may be coupled to receive a signal from an external transmission line at a first end of the internal transmission line without use of termination circuitry. The internal transmission line may transmit the signal passively to a second end of the internal transmission line. The integrated circuit may also comprise first circuitry having an input coupled to the internal transmission line at a first location of the internal transmission line to receive the signal and second circuitry having an input coupled to the internal transmission line at a second location of the internal transmission line to receive the signal. The second location may be different from the first location. Other embodiments are also disclosed.