CONTROLLING PASSTHROUGH OF COMMUNICATION BETWEEN MULTIPLE BUSES

• US 20110099310A1
• Filed: 12/30/2010
• Published: 04/28/2011
• Est. Priority Date: 05/21/2008
• Status: Active Grant

• Current Assignee: Dylan Hester, Ruifeng Sun, Scott Haban
• Original Assignee: Dylan Hester, Ruifeng Sun, Scott Haban
• Inventors: Sun, Ruifeng, Hester, Dylan, Haban, Scott
• Granted Patent: US 8,151,029 B2
• Time in Patent Office: Days
• US Class Current: 710/110
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247

Abstract

A demodulator can include first data and clock pads to couple the demodulator to a host device via a first bus, and second data and clock pads to couple the demodulator to a radio frequency (RF) tuner via a second bus. The device may further include passthrough logic to couple host data and a host clock from the first bus to the second bus and to couple tuner data from the second bus to the first bus during a passthrough mode. During this mode, however, the two buses may remain electrically decoupled. When the passthrough mode is disabled, the RF tuner is thus shielded from noise present on the first bus.

Claims

1-19. -19. (canceled)

20. An apparatus comprising:

a first data pad and a first clock pad to couple the apparatus to a host device via a first bus;

a second data pad and a second clock pad to couple the apparatus to a slave device via a second bus; and

passthrough logic to couple host data and a host clock from the first bus to the second bus and to couple data from the second bus to the first bus during a passthrough mode, wherein the first and second buses are electrically decoupled during the passthrough mode.

21. The apparatus of claim 20, further comprising a first input path from the first data pad to a slave controller of the apparatus and a second input path from the first data pad to the second data pad, wherein the first input path comprises a filtered path and the second input path comprises an unfiltered path.

22. The apparatus of claim 20, wherein the passthrough mode between the host device and the slave device is controlled by the host device.

23. The apparatus of claim 22, wherein the host device is to write a passthrough enable indicator to enable the passthrough mode, the passthrough mode to begin at an end of a data transaction from the host device including the passthrough enable indicator.

24. The apparatus of claim 22, wherein the host device is to enable the passthrough mode to provide information to the slave device and to disable the passthrough mode when the host device is to provide information to the apparatus.

25. The apparatus of claim 22, further comprising a slave controller to snoop passthrough communications during the passthrough mode and to control a direction of the passthrough communications through the first data pad and the second data pad.

26. The apparatus of claim 20, wherein the mirrored communication includes a first communication buffered by the first slave device, and the second slave device is to snoop communications on the first and second buses.

27. The apparatus of claim 20, wherein the first bus is to operate at a first voltage and the second bus is to operate at a second voltage

28. A system comprising:

a host device coupled to a first bus, the first bus coupled to a plurality of slave devices;

a first slave device coupled to the host device via the first bus and including a slave state machine to handle receipt and transmission of information on the first bus; and

a second slave device coupled to the first slave device via a second bus, wherein the second bus is to be disabled in absence of communications to or from the second slave device, and the slave state machine of the first slave device is to minor communication along the first bus to the second slave device via the second bus.

29. The system of claim 28, wherein the first slave device further comprises passthrough logic to buffer the communication along the first bus to the second bus without a direct electrical connection between the first and second buses.

30. The system of claim 28, wherein the first slave device includes:

a first data pad coupled to the first bus;

a second data pad coupled to the second bus;

a first input path from the first data pad to a slave controller of the first slave device; and

a second input path from the first data pad to the second data pad, wherein the first input path comprises a filtered path and the second input path comprises an unfiltered path.

31. The system of claim 30, wherein the first slave device includes:

a first output path from the slave controller of the first slave device to the first data pad; and

a second output path from the second data pad to the first data pad, wherein the first output path comprises a delayed path and the second output path comprises an undelayed path.

32. The system of claim 28, wherein the first slave device further comprises a first delay element clocked by a data signal of the first bus and to change state only when a clock signal of the first bus is in a high state.

33. The system of claim 32, wherein the mirrored communication is to begin when the first delay element changes state to an enable mode for the mirrored communication.

34. The system of claim 28, wherein the first bus is to operate at a first voltage and the second bus is to operate at a second voltage.

35. A method comprising:

determining whether a passthrough command has been received within a transaction from a host to a first slave device on a first bus to which a plurality of slave devices including the first slave device are coupled;

setting a passthrough mode indicator in a control register of the first slave device when the passthrough command has been received;

providing a passthrough enable signal to a passthrough circuit of the first slave device to enable a passthrough mode; and

buffering communications between the first bus and a second bus coupled between the first slave device and a second slave device in the passthrough mode, including providing the communications from an input pad of the first slave device to a state machine of the first slave device on a filtered path, and providing the communications from the input pad to an output pad of the first slave device coupled to the second bus on an unfiltered path.

36. The method of claim 35, further comprising snooping data and control information communicated on the first and second buses and analyzing the data and control information to determine a direction of communication flow between the host and the second slave device.

37. The method of claim 36, further comprising controlling the direction of communication flow via transmission of a direction signal based on the snooping.

38. The method of claim 35, further comprising buffering the communications without electrically coupling the first and second buses, the first and second buses operating at different voltages.