Embedded bus emulation
A bus emulation device in accordance with one aspect of the present description includes an embedded microcontroller and a nonvolatile memory carried on a body. The memory contains firmware which includes boot code adapted to boot the microcontroller to operate in one of a plurality of dedicated operating modes in response to a mode switch. These dedicated operating modes include a learning mode in which bus signals generated by other bus devices are recorded in the nonvolatile memory, and an emulation mode in which recorded bus signals are retransmitted over the bus in response to received signals, to emulate a bus device. Other aspects are described and claimed.
1. A bus emulation device for use with a bus, comprising:
a connector coupled to said bus and adapted to receive and transmit bus signals between said device and said bus, said bus signals including bus query and bus response signals;
an embedded microcontroller;
a mode switch; and
a nonvolatile memory including firmware stored therein, said firmware including boot code adapted to boot said microcontroller to operate in one of a plurality of dedicated modes in response to said mode switch, said dedicated modes including a learning mode and an emulation mode, wherein in said learning mode, said microcontroller is controlled by said firmware to record in said nonvolatile memory bus query signals received from said bus and to record in said nonvolatile memory, response signals received from said bus and associated with recorded query signals; and wherein in said emulation mode, said microcontroller is controlled by said firmware to transmit recorded response signals in response to receipt of associated query signals.
2. The emulation device of claim 1 wherein said firmware limits said microcontroller to be booted to operate in only one of two dedicated modes, said learning mode and said emulation mode.
3. The emulation device of claim 1 further comprising an address switch carried by said emulation device and configurable to define a bus address of said emulation device.
4. The emulation device of claim 1 for use with a target bus device coupled to said bus and having a bus address, said emulation further comprising an address switch carried by said device and configurable to define a bus address of said emulation device to be the same as said target bus device, wherein said operating said microcontroller in said learning mode includes recording in said nonvolatile memory of said microcontroller, response signals generated by said target bus device in response to recorded query signals.
5. The emulation device of claim 1 further comprising a single package carrying said connector, microcontroller, mode switch and nonvolatile memory.
6. The emulation device of claim 1 further comprising a single card carrying said connector, microcontroller, mode switch and nonvolatile memory.
7. The emulation device of claim 1 wherein said emulation device has exactly four connections terminals which are first and second input/output terminals of said connector, a power input connection terminals and a ground terminal.
8. The emulation device of claim 1 wherein said bus is a System Management Bus.
9. A method, comprising:
connecting an emulation device to a bus;
booting an embedded microcontroller of said emulation device using firmware stored in a nonvolatile memory of said emulation device, wherein said microcontroller is booted to operate in one of a plurality of dedicated modes including a learning mode and an emulation mode;
operating said microcontroller in said learning mode controlled by said firmware to record in a nonvolatile memory of said microcontroller, bus query signals received from said bus and to record in a nonvolatile memory of said microcontroller, response signals received from said bus and associated with recorded query signals; and
emulating a bus device, said emulating including operating said microcontroller in said emulation mode controlled by said firmware to receive bus query signals from said bus and transmit associated response signals over said bus.
10. The method of claim 9 further comprising switching said microcontroller to said dedicated learning mode using a mode switch carried by said emulation device.
11. The method of claim 9 further comprising switching said microcontroller to said dedicated emulation mode using a mode switch carried by said emulation device.
12. The method of claim 9 wherein said microcontroller is booted to operate in only one of two dedicated modes, said learning mode and said emulation mode.
13. The method of claim 9 further comprising configuring an address switch carried by said device to define a bus address of said device.
14. The method of claim 9 further comprising coupling a target bus device having a bus address, to said bus, configuring an address switch carried by said emulation device to define a bus address of said emulation device to be the same as said target bus device, wherein said operating said microcontroller in said learning mode includes recording in a nonvolatile memory of said microcontroller, response signals generated by said target bus device in response to recorded query signals.
15. The method of claim 9 wherein said bus is a System Management Bus.