Single wire bus system

• US 8,775,707 B2
• Filed: 12/02/2010
• Issued: 07/08/2014
• Est. Priority Date: 12/02/2010
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Poulsen, Jens Kristian
• Primary Examiner(s): Spittle, Matthew D
• Application Number:
  US12/958,942
• Publication Number:
  US 20120144078A1
• Time in Patent Office: 1,314 Days
• Field of Search: 710/110, 710/105, 710/106, 711/115
• US Class Current: 710/110
• CPC Class Codes: G06F 13/423 with synchronous protocol
• CPC Class Codes: G06F 13/4291 using a clocked protocol
• CPC Class Codes: G06F 13/4295 using an embedded synchronisation

Abstract

There is provided a single wire bus architecture comprising a single wire bus; a master device coupled to the single wire bus; at least one slave device coupled to the single wire bus; a communication protocol implemented over the single wire bus and employed by the master device and the at least one slave device; wherein when one of the at least one slave devices wishes to communicate with the master device, the one of the at least one slave devices discharges the clock signal during a tri-state stage of the clock signal; and wherein the single wire bus transmits a clock signal, power and data between the master device and the one of the at least one slave device in communication with the master device.

Claims

1. A single wire bus architecture comprising:

a single wire bus;

a master device coupled to the single wire bus;

at least one slave device coupled to the single wire bus;

a delay unit having two capacitors that are alternately charged by a fixed current so that a charging voltage on the capacitors is used to determine points where the single wire bus is activated and sampled; and

a communication protocol implemented over the single wire bus for communication between the master device and the at least one slave device;

wherein the communication protocol employs the use of a continuous clock signal and bi-directional data transmission within each clock cycle for communication between the master device and the at least one slave device;

wherein the bus is in a tri-state period during bi-directional data transmission in which one of the master device or the at least one slave device can pull down or leave the clock signal unchanged to signal a data value; and

wherein timing between the continuous clock signal and the bi-directional data is defined by leading and trailing edges of each clock cycle.

2. The single wire bus architecture of claim 1 wherein unique time-slots are used for transmission of the continuous clock signal and the bi-directional data.

3. The single wire bus architecture of claim 2 wherein pulling the bus high signals a leading edge for the continuous clock signal.

4. The single wire bus architecture of claim 3 wherein pulling the bus low in the time slot assigned for bi-directional data represents a logical data value of “

1” and

leaving it unchanged represents a logical data value of “

0”

.

5. The single wire bus architecture of claim 3 wherein pulling the bus low in the time-slot assigned for bi-directional data represents a logical data value of “

0” and

leaving it unchanged represents a logical data value of “

1”

.

6. The single wire bus architecture of claim 1 wherein pulling the bus high signals a leading edge for the continuous clock signal.

7. The single wire bus architecture of claim 1 wherein pulling the bus low signals a leading edge for the continuous clock signal.

8. The single wire bus architecture of claim 7 wherein pulling the bus high in the time slot assigned for bi-directional data represents a logical data value of “

1” and

leaving it unchanged represents a logical data value of “

0”

.

9. The single wire bus architecture of claim 7 wherein pulling the bus high in the time slot assigned for bi-directional data represents a logical data value of “

0” and

leaving it unchanged represents a logical data value of “

1”

.

10. The single wire bus architecture of claim 1 wherein one of the at least one slave devices is a headset.

11. The single wire system of claim 1, where the master device drives the continuous clock signal and leaves the bus in a floating or weakly driven state for the bi-directional data time slot.

12. The single wire bus architecture of claim 1 wherein a frame of data comprises a set of control words.

13. The single wire bus architecture of claim 12 wherein the set of control words comprises at least one synchronization word and words used for controlling devices attached to the bus.

14. The single wire bus architecture of claim 13, where the synchronization word is used for synchronization and the synchronization word comprises a constant value and a pseudorandom portion.

15. The single wire bus architecture of claim 12 wherein the bits of the control words are transmitted individually in a predetermined sequence.

16. The single wire bus architecture of claim 15 wherein the bits of the control words are transmitted consecutively and audio data is transmitted between the control words and within a given frame of data.

17. The single wire bus architecture of claim 1, where the single wire bus is used for powering the at least one slave device.

18. The single wire bus architecture of claim 1, wherein an external device is synchronized to the bus using controlled delays with a low-to-high or a high-to-low edge triggered Phase-Lock Loop (PLL), a Delay Locked Loop (DLL) or a fixed delay circuit, wherein the external device comprises the at least one slave device.

19. A single wire bus architecture comprising:

a single wire bus;

a master device coupled to the single wire bus;

at least one slave device coupled to the single wire bus; and

a delay unit having two capacitor s that are alternately charged by a fixed current so that a charging voltage on the capacitors is used to determine points where the single wire bus is activated and sampled,

wherein the master device and the at least one slave device communicate by time-multiplexing a set of bus cycles, each of the bus cycles including a clock signal portion and a bi-directional data transmission portion for data transmission between the master device and the at least one slave device, wherein during said bi-directional data transmission portion the bus is in a tri-state period in which one of the master device or the at least one slave device can pull down or leave the clock signal unchanged to signal a data value; and

, wherein discharging of the clock signal by either the master device or the at least one slave device occurs after a particular time period and within each bus cycle.

20. The single wire bus architecture of claim 19 wherein a percentage of the bus cycle is used for communicating the continuous clock signal and a remaining percentage of the bus cycle is used for the bi-directional data transmission.

21. The single wire bus architecture of claim 20 wherein reading of the bus state, either in a discharged or a charged state, by the master device or the at least one slave device occurs after a second particular period of time within each bus cycle.

22. The single wire bus architecture of claim 19, wherein an external device is synchronized to the bus using controlled delays with a low-to-high or a high-to-low edge triggered Phase-Lock Loop (PLL), a Delay Locked Loop (DLL) or a fixed delay circuit, wherein the external device comprises that at least one slave device.