Apparatus and method for operating and switching a single conductor interface

1. A method for communicating between a master device and a slave device using a first single conductor, the method comprising:

transmitting a first ping on the first single conductor using a master device, the first single conductor configured to couple the master device to a slave device;

receiving a slave ping on the first single conductor at the master device during a ping interval;

authenticating the slave device after receiving the slave ping, wherein the authenticating includes:

transmitting a random number from the master to the slave;

receiving an encrypted number from the slave;

decrypting the encrypted number to provide a decrypted number; and

indicating a valid authentication if the decrypted number matches the random number;

transmitting data packets from the master device to the slave device using the first single conductor, wherein transmitting data packets includes toggling a logic level of the first single conductor prior to sending a first data packet using pulses having a duration of less than one half of a unit interval, wherein the unit interval defines a single bit duration of transmitted data; and

wherein a ping, including the first ping and the slave ping, includes a duration of more than a unit interval.

2. The method of claim 1 , wherein the transmitting the master ping includes releasing electrical control of the first single conductor; and

waiting to receive the slave ping during the ping interval.

3. The method of claim 1 , wherein the transmitting data packets includes transmitting multi-byte data packets.

4. The method of claim 3 , wherein transmitting multi-byte data packets includes transmitting a plurality of bytes, wherein each byte includes a plurality of data bits and a parity bit.

5. The method of claim 1 , wherein transmitting data packets includes transmitting an end-of-packet ping to indicate an end of each packet of the data packets.

6. The method of claim 1 , including switching communications from the first single conductor to a second single conductor.

7. The method of claim 6 , wherein the switching includes:

receiving a switch command from a host processor at the master device;

transmitting a switch command to the slave using the first single conductor;

transmitting master pings using the first single conductor and the second single conductor; and

receiving a second slave ping on the second single conductor.

8. The method of claim 7 , wherein switching includes:

resending switch command to the slave device using the second single conductor;

receiving a switch acknowledgement from the slave using the second single conductor; and

transmitting an interrupt to the host device indicating completion of a communication switch from the first single conductor to the second single conductor.

9. The method of claim 1 , including resetting communications between the master device and the slave device;

wherein the resetting includes transmitting a reset pulse over the single conductor using the master device; and

wherein the reset pulse includes a duration longer than a duration of the master ping.

10. The method of claim 9 , wherein the reset pulse has a duration more than five times longer than the duration of the master ping.

11. The method of claim 1 , wherein the master ping includes a duration that is more than ten times longer than the unit interval.

12. A method for communicating between a master device and a slave device using a first single conductor; the method comprising:

receiving a first master ping at a slave device using the first single conductor;

transmitting a first slave ping from the slave device using the first single conductor;

receiving an authentication command and a random number from the master at the slave device using the first single conductor;

encrypting the random number to provide an encrypted number; and

transmitting the encrypted number to the master using the first single conductor; and

receiving data packets from the master device at the slave device using the first single conductor, wherein receiving data packets includes receiving a plurality of pulses having a duration of less than one half of a unit interval, wherein the unit interval defines a single bit duration of transmitted data.

13. The method of claim 12 , wherein transmitting a first slave ping includes releasing the electrical control of the first single conductor and delaying at least one unit interval before detecting the master electrically controlling the first single conductor.

14. The method of claim 12 , wherein transmitting a first slave ping includes releasing the electrical control of the first single conductor; and

wherein the method includes delaying between three unit intervals and five unit intervals before taking control of the first single conductor to send slave information to the master using the first single conductor.

15. The method of claim 12 , including transmitting slave data packets to the master device using the first single conductor.

16. The method of claim 15 , wherein transmitting slave data packets includes transmitting an end-of-packet ping to indicate an end of each packet of the slave data packets.

17. The method of claim 12 , including receiving a switch command from the master device at the slave device using the first single conductor;

transmitting a first switch command acknowledgement from the slave device to the master device using the first single conductor;

receiving master pings on both the first single conductor and a second single conductor at the slave device;

transmitting a second slave ping on the second single conductor in response to one or more master pings received on the second single conductor;

receiving a copy of the switch command on the second single conductor at the slave device; and

transmitting a second switch command acknowledgement from the slave device to the master device using the second single conductor.

18. A transceiver for communicating over a single conductor, the transceiver comprising:

a processor configured to transmit a first ping on a first single conductor, the first single conductor configured to couple the transceiver with a slave device, to receive a slave ping on the first single conductor during a ping interval, to transmit data packets to the slave device using the first single conductor, to toggle a logic level of the first single conductor prior to sending a first data packet using pulses having a duration of less than one half of a unit interval, wherein the unit interval defines a single bit duration of transmitted data, and wherein a ping, including the first ping and the slave ping, includes a duration of more than a unit interval; and

wherein the processor is further configured to transmit a random number to the slave, to receive an encrypted number from the slave, to decrypt the encrypted number to provide a decrypted number, and to indicate a valid authentication of the slave if the decrypted number matches the random number.

19. A transceiver for communicating over a single conductor, the transceiver comprising:

a processor configured to receive a first master ping from a master device coupled to the first single conductor, to transmit a first slave ping on the first single conductor in response to the master ping, to receive data packets from the master device using the first single conductor, and to receive a plurality of pulses having a duration of less than one half of a unit interval immediately prior to receiving each data packet of the data packets, wherein the unit interval defines a single bit duration of transmitted data; and

wherein the processor is further configured receive an authentication command and a random number from the master using the first single conductor, to encrypt the random number to provide an encrypted number, and to transmit the encrypted number to the master using the first single conductor.

20. A transceiver for communicating over a single conductor, the transceiver comprising:

a processor configured to receive a first master ping from a master device coupled to the first single conductor, to transmit a first slave ping on the first single conductor in response to the master ping, to receive data packets from the master device using the first single conductor, and to receive a plurality of pulses having a duration of less than one half of a unit interval immediately prior to receiving each data packet of the data packets, wherein the unit interval defines a single bit duration of transmitted data; and

wherein the processor is further configured to receive a switch command from the master device using the first single conductor, to transmit a first switch command acknowledgement to the master device using the first single conductor, to receive master pings on both the first single conductor and a second single conductor, to transmit a second slave ping on the second single conductor in response to one or more master pings received on the second single conductor, to receive a copy of the switch command on the second single conductor, and to transmit a second switch command acknowledgement to the master device using the second single conductor.

21. A method for communicating between a master device and a slave device using a first single conductor, the method comprising:

transmitting a first ping on the first single conductor using a master device, the first single conductor configured to couple the master device to a slave device;

receiving a slave ping on the first single conductor at the master device during a ping interval;

transmitting data packets from the master device to the slave device using the first single conductor, wherein transmitting data packets includes toggling a logic level of the first single conductor prior to sending a first data packet using pulses having a duration of less than one half of a unit interval, wherein the unit interval defines a single bit duration of transmitted data; and

switching communications from the first single conductor to a second single conductor;

wherein a ping, including the first ping and the slave ping, includes a duration of more than a unit interval; and

wherein the switching includes:

receiving a switch command from a host processor at the master device;

transmitting a switch command to the slave using the first single conductor;

transmitting master pings using the first single conductor and the second single conductor; and

receiving a second slave ping on the second single conductor.

22. A method for communicating between a master device and a slave device using a first single conductor, the method comprising:

receiving a first master ping at a slave device using the first single conductor;

transmitting a first slave ping from the slave device using the first single conductor;

receiving data packets from the master device at the slave device using the first single conductor, wherein receiving data packets includes receiving a plurality of pulses having a duration of less than one half of a unit interval, wherein the unit interval defines a single bit duration of transmitted data;

receiving a switch command from the master device at the slave device using the first single conductor;

transmitting a first switch command acknowledgement from the slave device to the master device using the first single conductor;

receiving master pings on both the first single conductor and a second single conductor at the slave device;

transmitting a second slave ping on the second single conductor in response to one or more master pings received on the second single conductor;

receiving a copy of the switch command on the second single conductor at the slave device; and

transmitting a second switch command acknowledgement from the slave device to the master device using the second single conductor.