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A communication bus system is provided. The communication bus system includes a communication bus having a plurality of isolatable segments and a bus master coupled to a first end of the communication bus. The bus master is configured to couple to a second end of the communication bus and to decoupl

A communication bus system is provided. The communication bus system includes a communication bus having a plurality of isolatable segments and a bus master coupled to a first end of the communication bus. The bus master is configured to couple to a second end of the communication bus and to decouple from the second end of the communication bus based on a selection signal. A method for operating a communication bus is also disclosed.

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1. A communication bus system, comprising: a communication bus having a plurality of isolatable segments that are coupled and decoupled to the communication bus by a plurality of switches, wherein the plurality of switches are powered or operated by a plurality of charge pumps coupled to the communi

1. A communication bus system, comprising: a communication bus having a plurality of isolatable segments that are coupled and decoupled to the communication bus by a plurality of switches, wherein the plurality of switches are powered or operated by a plurality of charge pumps coupled to the communication bus and wherein the plurality of charge pumps are configured to detect activity on the communication bus;a bus master having a first port coupled to a first end of the communication bus, the bus master configured to couple the first port, via a switch, to a second port of the bus master coupled to a second end of the communication bus and to decouple the first port from the second port and the second end of the communication bus based on a selection signal;the switch configured to have a closed state, responsive to a first state of the selection signal, with the bus master coupled to and communicative with the first end of the communication bus via the first port and the bus master communicative with and coupled via the first port and the closed switch to the second port and the second end of the communication bus;the switch configured to have an open state, responsive to a second state of the selection signal, with the first port coupled to the first end of the communication bus and the first port decoupled, via the open switch, from the second port and the second end of the communication bus;the bus master having a differential amplifier coupled to a resistor ladder that biases the communication bus to a specified differential voltage that is received by the differential amplifier, wherein the resistor ladder coupled to the first port and second port establishes about 0.9V on the communication bus at a bus idle state and establishes a termination impedance of the communication bus; andthe differential amplifier, having differential inputs coupled to the first port and the second port, converts the specified differential voltage to a logical zero or a logical one. 2. The communication bus system of claim 1, further comprising: a plurality of bus slaves coupled along the communication bus, each bus slave of the plurality of bus slaves having one of the plurality of switches, wherein a first terminal of the one of the plurality of switches is coupled to a first isolatable segment of the communication bus and a second terminal of the one of the plurality of switches is coupled to a second isolatable segment of the communication bus. 3. The communication bus system of claim 1, wherein the bus master is coupled to each wire of the communication bus through the switch. 4. The communication bus system of claim 1, further comprising: a plurality of bus slaves coupled along the communication bus, each bus slave of the plurality of bus slaves configured to receive communication from either of two of the segments to which the slave is coupled, irrespective of whether the two of the segments are decoupled from each other by the slave. 5. The communication bus system of claim 1, further comprising: the bus master is configured to communicate with a first one of a plurality of bus slaves via the first end of the communication bus while the bus master is decoupled from the second end of the communication bus; andthe bus master is configured to communicate with a second one of the plurality of bus slaves via the second end of the communication bus while the bus master is coupled to the second end of the communication bus, regardless of whether the communication bus is severed between the first one of the plurality of bus slaves and the second one of the plurality of bus slaves. 6. The communication bus system of claim 1, wherein the communication bus system comprises: a plurality of bus slaves coupled to the communication bus, each bus slave of the plurality of bus slaves having back-to-back PMOSFETs (P type metal oxide semiconductor field effect transistors) coupled to the isolatable segments of the communication bus as one of the plurality of switches; andeach bus slave of the plurality of bus slaves having one of the plurality of charge pumps coupled to the communication bus and coupled to a midpoint of the back-to-back PMOSFETs. 7. The communication bus system of claim 1, wherein: the bus master includes a double pole switch, as the switch, coupled via the second port to the second end of the communication bus, with the first port of the bus master being decoupled from the second end of the communication bus when the double pole switch is open; andeach of the plurality of bus slaves includes a single pole switch, as one of the plurality of switches, coupled to the segments of the communication bus, with the segments of the communication bus being decoupled when the single pole switch is open. 8. The communication bus system of claim 1, wherein the bus master includes: the switch, coupled to the first port and the second port. 9. A communication bus system, comprising: a communication bus having a ring topology;a bus master coupled by a first port to a first end of the communication bus, with a second port of the bus master coupled to a second end of the communication bus, the bus master having a first switch configured couple the first port to the second port of the bus master and to selectably break the ring topology by decoupling the first port of the bus master from the second port of the bus master while the bus master remains in communication with the communication bus via the first port;the first switch configured to close responsive to a first state of a selection signal so that the bus master is communicative with and coupled to the first end of the communication bus via the first port and the bus master is communicative with and coupled via the first port and the closed first switch to the second port and the second end of the communication bus;the first switch configured to open responsive to a second state of the selection signal so that the bus master is coupled to the first end of the communication bus via the first port and the bus master and the first port are decoupled, via the open first switch, from the second port and the second end of the communication bus;a plurality of bus slaves coupled to the communication bus, each slave of the plurality of bus slaves having a switch configured, through a charge pump coupled to the communication bus and configured to detect activity on the communication bus, to couple and decouple neighboring segments of the communication bus;the bus master having a differential amplifier coupled to a resistor ladder that biases the communication bus to a specified differential voltage that is received by the differential amplifier, wherein the resistor ladder coupled to the first port and second port establishes about 0.9V on the communication bus at a bus idle state and establishes a termination impedance of the communication bus; andthe differential amplifier, having differential inputs coupled to the first port and the second port, converts the specified differential voltage to a logical zero or a logical one. 10. The communication bus system of claim 9, wherein: the first switch has terminals coupled by the first port to a first segment of the communication bus and has terminals coupled by the second port to a second segment of the communication bus and;the bus master is coupled to the first segment of the communication bus. 11. The communication bus system of claim 9, wherein the first switch includes a plurality of switches, wherein one of the plurality of switches is dedicated to a wire of the communication bus. 12. The communication bus system of claim 9, wherein each bus slave of the plurality of bus slaves comprises: a first diode coupled from a wire of a first segment of the communication bus to a receiver terminal of the bus slave; anda second diode coupled from a wire of a second segment of the communication bus to the receiver terminal of the bus slave. 13. The communication bus system of claim 9, wherein: the switch configured to couple and decouple neighboring segments includes back-to-back PMOSFETs (P type metal oxide semiconductor field effect transistors) coupled to the neighboring segments of the communication bus. 14. The communication bus system of claim 9, further comprising: a switch control that operates the switch configured to couple and decouple neighboring segments; andthe switch configured to couple and decouple neighboring segments, and the switch control, wherein the charge pump provides electrical power to the switch control. 15. The communication bus system of claim 9, further comprising: an optoisolator coupled to the communication bus and the switch configured to couple and decouple neighboring segments, the optoisolator configured to operate the switch configured to couple and decouple the neighboring segments of the communication bus. 16. A method of operating a communication bus, comprising: decoupling, as a result of inactivity on the communication bus, isolatable segments of the communication bus that are coupled by a plurality of switches, wherein the plurality of switches are powered or operated by a plurality of charge pumps coupled to the communication bus and configured to detect activity on the communication bus;opening a switch so as to decouple a first port of a bus master from a second port of the bus master and a first end of a communication bus, wherein the bus master has a differential amplifier coupled to a resistor ladder;biasing the communication bus to a specified differential voltage that is received by the differential amplifier;transmitting a message to one of a plurality of bus slaves via the first port and a second end of the communication bus, with the decoupling from the first end of the communication bus being maintained; andclosing the switch so as to couple the first port to the second port and the first end of the communication bus, with the bus master communicative with the second port and the first end of the communication bus via the first port and the closed switch and with the first port bus master remaining coupled to and communicative with the second end of the communication bus via the first port. 17. The method of claim 16, further comprising: iteratively transmitting messages to next ones of the plurality of bus slaves via the second end of the communication bus until either all of the messages have been successfully sent to the bus slaves or a bad connection is encountered;determining whether the bad connection is encountered; anditeratively transmitting at least a subset of the messages to at least a subset of the plurality of bus slaves in reverse order via the first end of the communication bus, in response to a determination that the bad connection is encountered. 18. The method of claim 16, further comprising: communicating with the plurality of bus slaves via the second end of the communication bus and the first end of the communication bus, after the configuring and the coupling. 19. The method of claim 16, wherein decoupling from the first end of the communication bus and coupling to the first end of the communication bus include operating a switch that decouples the first port of the bus master from the second port of the bus master and the first end of the communication bus and couples the first port of the bus master to the second port of the bus master and the first end of the communication bus. 20. The method of claim 16, further comprising: routing a transmission expressed on the first end of the communication bus through a bypass device to a receiver of one of the plurality of bus slaves.