Method for supporting multiple devices on a high speed physical link

• US 8,335,229 B1
• Filed: 02/04/2010
• Issued: 12/18/2012
• Est. Priority Date: 12/31/2003
• Status: Expired due to Fees

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Mueller, Peter D., Fullerton, Mark N., Nossenson, Nir
• Primary Examiner(s): ZHU, BO HUI ALVIN
• Application Number:
  US12/700,100
• Time in Patent Office: 1,048 Days
• Field of Search: 370/433, 370/438, 370/439, 370/445, 370/447, 710/109, 710/110, 710/220, 710/260, 710/261, 710/262, 710/263, 710/264, 710/265, 710/266, 710/267, 710/268, 710/269, 700/2.3
• US Class Current: 370/439
• CPC Class Codes: G06F 13/36 for access to common bus or bus system
• CPC Class Codes: G06F 13/4226 with asynchronous protocol

Abstract

In some embodiments, a method for supporting multiple devices on a high speed physical link may be described. An embedded device may assert a link request pin to request to transmit data on a multi-point communications link that may serve a plurality of embedded devices. A controlling device may receive the link request signal. When the controlling device finishes sending data on the link, it may address the plurality of embedded devices in a round robin format and may determine which device asserted the link request pin. The embedded device that asserted the link request pin may send an acknowledgement signal to the controlling device when it is addressed.

Claims

1. A handheld device comprising:

a plurality of embedded microprocessor devices; and

an inter-device communication link configured to provide a data link between the plurality of embedded microprocessor devices, wherein at a given time, the plurality of embedded microprocessor devices comprises;

only one embedded microprocessor device configured as a controlling device that has permission to transmit data on the inter-device communication link; and

a plurality of non-controlling devices that lack permission to transmit data on the inter-device communication link, each configured to activate a link request pin to request to become the controlling device in order to have permission to transmit data on the inter-device communication link,

wherein, in response to an activation of the link request pin, the controlling device is configured to;

initiate an arbitration to determine which one of the plurality of non-controlling devices activated the link request pin to become the controlling device to have permission to transmit data on the inter-device communication link; and

handoff the permission to transmit data on the inter-device communication link to one of the plurality of non-controlling devices based on the arbitration, and

wherein, upon handoff, the one of the plurality of non-controlling devices receiving the permission is configured to become the controlling device operable to initiate another arbitration based on a subsequent activation of the link request pin by any of the plurality non-controlling devices,

wherein the controlling device is configured to initiate the arbitration by being configured to address the non-controlling devices to determine which of the plurality of non-controlling devices activated the link request pin to become the controlling device to have permission to transmit data on the inter-device communication link, and

wherein the controlling device is configured to address the non-controlling device by being configured to;

activate a strobe pin and one or more device IDs of the non-controlling devices; and

receive a confirmation signal from the one of the plurality of non-controlling devices that activated the link request pin.

2. The handheld device of claim 1, wherein the link request pin is shared between the plurality of embedded microprocessor devices.

3. The handheld device of claim 1, wherein the arbitration is performed using a round robin method to determine which one of the plurality non-controlling devices activated the link request pin.

4. The handheld device of claim 1, wherein the inter-device communication link further includes a clock pin configured to be activated to control flow of data on the inter-device communication link.

5. The handheld device of claim 4, wherein the clock pin is driven only when data is being transferred on the inter-device communication link.

6. The handheld device of claim 4, wherein the inter-device communication link further includes a wait pin configured to be asserted by any given non-controlling device in response to the given non-controlling device not being able to accept data from the controlling device.

7. The handheld device of claim 1, wherein the plurality of embedded microprocessor devices includes one or more of a general application processor device, a baseband processor device, a processor for hardware accelerator applications, a processor for audio code/decode (CODEC) applications, or a processor for digital signal processing.

8. The handheld device of claim 7, wherein the baseband processor comprises a Code Division Multiple Access (CDMA) processor, a Wideband Code Division Multiple Access (WCDMA) processor, a Bluetooth processor, or an IEEE 802.11 processor.

9. The handheld device of claim 1, wherein the handheld device comprises a cellular phone, a notebook computer, a handheld computer, or a personal digital assistant.

10. A method for transmitting data between a plurality of embedded microprocessor devices on an inter-device communication link, wherein at a given time, the plurality of embedded microprocessor devices comprises only one embedded microprocessor device configured as a controlling device that has permission to transmit data on the inter-device communication link and a plurality of non-controlling devices that lack permission to transmit data on the inter-device communication link, each configured to activate a link request pin to request to become the controlling device in order to have permission to transmit data on the inter-device communication link, the method comprising:

any of the plurality of non-controlling devices activating the link request pin to become the controlling device and transmit the data on the inter-device communication link; and

in response to the activation of the link request pin, the controlling device;

initiating an arbitration to determine which one of the plurality of non-controlling devices activated the link request pin to become the controlling device to have permission to transmit data on the inter-device communication link; and

handing off the permission to transmit data on the inter-device communication link to one of the non-controlling devices based on the arbitration,

wherein, upon handoff, the one of the non-controlling devices receiving the permission is configured to become the controlling device operable to initiate another arbitration based on a subsequent activation of the link request pin by any of the non-controlling devices,

wherein initiating the arbitration comprises;

addressing the non-controlling devices to determine which of the plurality of non-controlling devices activated the link request pin to become the controlling device to have permission to transmit data on the inter-device communication link, and

wherein addressing the non-controlling devices comprises;

activating a strobe pin and one or more a device IDs of the non-controlling devices; and

receiving a confirmation signal from the one of the plurality of non-controlling devices that activated the link request pin.

11. The method of claim 10, wherein the link request pin is shared between the plurality of embedded microprocessor devices.

12. The method of claim 10, wherein the arbitration is performed using a round robin method to determine which one of the plurality of non-controlling devices activated the link request pin.

13. The method of claim 10, wherein:

the inter-device communication link includes a clock pin configured to be activated to control flow of data on the inter-device communication link; and

the method further includes driving the clock pin only when data is being transferred on the inter-device communication link.

14. The method of claim 10, wherein the plurality of embedded microprocessor devices includes one or more of a general application processor device, a baseband processor device, a processor for hardware accelerator applications, a processor for audio code/decode (CODEC) applications, or a processor for digital signal processing.

15. The method of claim 14, wherein the baseband processor comprises a Code Division Multiple Access (CDMA) processor, a Wideband Code Division Multiple Access (WCDMA) processor, a Bluetooth processor, or an IEEE 802.11 processor.

16. An apparatus comprising:

at a given time, only one embedded microprocessor device configured as a controlling device that has permission to transmit data on an inter-device communication link to a plurality of embedded microprocessor devices that lack permission to transmit data on the inter-device communication link, wherein the controlling device is configured to;

determine an activation of a link request pin by one of the plurality of non-controlling devices, the link request pin being activated by the one of the non-controlling devices to become the controlling device in order to have permission to transmit data on the inter-device communication link; and

in response to determination of activation of the link request pin,

perform an arbitration by addressing the plurality of non-controlling devices to determine which one of the plurality of non-controlling devices activated the link request pin to become the controlling devices to have permission to transmit data on the inter-device communication link; and

handoff the permission to transmit data on the inter-device communication link to the one of the non-controlling devices based on the arbitration,

wherein the controlling device is configured to perform the arbitration by being configured to address the non-controlling devices to determine which of the plurality of non-controlling devices activated the link request pin to become the controlling device to have permission to transmit data on the inter-device communication link, and

wherein the controlling device is configured to address the non-controlling device by being configured to;

activate a strobe pin and one or more device IDs of the non-controlling devices; and

receive a confirmation signal from the one of the plurality of non-controlling devices that activated the link request pin.