阅读说明：本技术 具有时钟域相关的usb设备 (USB device with clock domain correlation ) 是由 R·李 P·沙哈 M·希恩科 H·L·尼尔森 S·罗勒 A·梅拉比 S·穆勒 R·赫尔 于 2018-06-28 设计创作，主要内容包括：提出了与时钟域相关的方法和USB设备。USB设备包括被适配成在第一时钟域中携带信号的至少一条信号线。这些信号是从USB主机接收的。时钟操作第二时钟域。周期性分组检测电路从在第一时钟域中所接收的信号检测丢失的周期性分组。设备控制器基于周期性分组检测电路检测到丢失的周期性分组而将第二时钟域中的USB操作与第一时钟域相关。USB设备包括携带UTMI或ULPI信令的至少一条信号线。USB控制器对来自UTMI或ULPI信令中的分组标识进行解码。与USB控制器分开的周期性分组检测电路对来自UTMI或ULPI信令中的分组标识进行解码。(Methods and USB devices related to a clock domain are presented. The USB device includes at least one signal line adapted to carry a signal in a first clock domain. These signals are received from the USB host. The clock operates a second clock domain. The periodic packet detection circuit detects a missing periodic packet from a signal received in the first clock domain. The device controller correlates USB operations in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting a missing periodic packet. The USB device includes at least one signal line carrying UTMI or ULPI signaling. The USB controller decodes the packet identification from UTMI or ULPI signaling. Periodic packet detection circuitry, separate from the USB controller, decodes the packet identification from UTMI or ULPI signaling.)

1. A Universal Serial Bus (USB) device, comprising:

at least one signal line adapted to carry a signal in a first clock domain, the signal received from a USB host;

operating a clock of a second clock domain;

a periodic packet detection circuit adapted to detect missing periodic packets from the signal received in the first clock domain; and

a device controller adapted to correlate USB operations in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting the missing periodic packets.

2. The USB device of claim 1, wherein the lost periodic packets comprise start of frame (SOF) packets.

3. The USB device of claim 1, wherein the signal received in the first clock domain comprises USB 2.0 transceiver macro cell interface (UTMI) or UTMI + low pin interface (ULPI) signaling.

4. The USB device of claim 3, wherein the periodic packet detection circuit is adapted to decode packet identifications in the received signal in the first clock domain to detect the missing periodic packets;

further comprising:

a USB controller separate from the periodic packet detection circuit, the USB controller adapted to decode packet identifications in signals received in the first clock domain.

5. The USB device of claim 3, wherein the device controller is adapted to determine feedback to the USB host to adjust a transmission data rate to correlate the USB operation in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting the missing periodic packets.

6. The USB device of claim 1, wherein the periodic packet detection circuit is adapted to generate recovered periodic packet signaling.

7. The USB device of claim 6, wherein the device controller is adapted to determine feedback to the USB host based on the recovered periodic packet signaling to adjust a transmission data rate to correlate the USB operation in the second clock domain with the first clock domain.

8. A method for operating a USB device, comprising:

providing a signal in a first clock domain, the signal received from a USB host;

detecting missing periodic packets from the received signal in the first clock domain; and

correlating USB operations in a second clock domain with the first clock domain based on detecting the lost periodic packets.

9. The method of claim 8, wherein the lost periodic packets comprise start of frame (SOF) packets.

10. The method of claim 8, wherein the signal received in the first clock domain comprises USB 2.0 transceiver macro cell interface (UTMI) signaling or UTMI + low pin interface (ULPI).

11. The method of claim 10, wherein detecting the missing periodic packet comprises decoding a packet identification in the received signal in the first clock domain;

further comprising:

decoding a second packet identification in the received signal in the first clock domain independently of detecting the missing periodic packet.

12. The method of claim 10, wherein correlating the USB operation in the second clock domain with the first clock domain comprises: determining feedback to the USB host to adjust a transmission data rate.

13. The method of claim 8, further comprising generating recovered periodic packet signaling.

14. The method of claim 13, wherein correlating the USB operation in the second clock domain with the first clock domain comprises: determining feedback to the USB host to adjust a transmission data rate based on the recovered periodic packet signaling.

15. A USB device, comprising:

at least one signal line adapted to carry UTMI or ULPI signaling;

a USB controller adapted to decode a packet identification in the UTMI or ULPI signaling; and

a periodic packet detection circuit separate from the USB controller adapted to decode a packet identification in the UTMI or ULPI signaling.

16. The USB device of claim 15, wherein the periodic packet detection circuit is adapted to detect missing periodic packets from decoded packet identifications.

17. The USB device of claim 16, wherein the lost periodic packets are SOF packets.

18. The USB device of claim 16, wherein the UTMI signaling is in a first clock domain;

further comprising:

the clock of the second clock domain is operated.

19. The USB device of claim 18, further comprising:

a device controller adapted to correlate USB operations in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting the missing periodic packets.

20. The USB device of claim 19, wherein the device controller is adapted to determine feedback to a USB host to adjust a transmission data rate to correlate the USB operation in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting the lost periodic packets.

21. The USB device of claim 15, wherein the periodic packet detection circuit is adapted to generate recovered periodic packet signaling.

22. The USB device of claim 21, wherein the UTMI or ULPI signaling is in a first clock domain;

further comprising:

a device controller adapted to determine feedback to a USB host to adjust a transmission data rate based on the recovered periodic packet signaling to correlate USB operations in a second clock domain with the first clock domain.

23. A method for operating a USB device, comprising:

decoding the packet identification in the UTMI or ULPI signaling via a first decoding path; and

decoding a second packet identification in the UTMI or ULPI signaling via a second decoding path, the second decoding path being independent of the first decoding path.

24. The method of claim 23, further comprising: missing periodic packets are detected from the decoded packet identification.

25. The method of claim 24, wherein the lost periodic packets are SOF packets.

26. The method of claim 24, wherein the UTMI signaling is in a first clock domain;

further comprising:

the USB operation is operated in a second clock domain.

27. The method of claim 26, further comprising:

correlating the USB operations in the second clock domain with the first clock domain based on detecting the missing periodic packets.

28. The method of claim 27, wherein correlating the USB operation in the second clock domain with the first clock domain comprises: determining feedback to the USB host to adjust a transmission data rate based on detecting the lost periodic packets.

29. The method of claim 23, further comprising: recovered periodic packet signaling is generated.

30. The method of claim 29, wherein the UTMI or ULPI signaling is in a first clock domain;

further comprising:

correlating USB operations in a second clock domain with the first clock domain comprises: feedback to the USB host is determined based on the recovered periodic packet signaling to adjust the transmission data rate.

Technical Field

Certain aspects of the present disclosure generally relate to Universal Serial Bus (USB) devices, and more particularly to USB devices related to a clock domain.

Background

A USB system may include a USB host and a USB device (such as a headset). A USB host (e.g., mobile terminal, laptop, desktop, etc.) may be connected to a device for voice calls or audio playback. Thus, the USB host may provide audio data to the USB device in various formats (e.g., MP3, HiFi audio). A USB host may sometimes be referred to as a source (e.g., of audio data), while a USB device may sometimes be referred to as a sink (e.g., of audio data). The USB host and the USB device may run on different clock domains. For example, a USB host may operate on a host clock (and, therefore, on a host clock domain), while a USB device may operate on a device clock (and, therefore, on a device clock domain). These two clocks may exhibit clock drift (parts per million (ppm)) due to, for example, different crystals and temperature variations. Thus, there is a need for USB devices to operate on data across different clock domains.

SUMMARY

This summary identifies features of some example aspects and is not an exclusive or exhaustive description of the disclosed subject matter. Whether features or aspects are included in or omitted from this summary is not intended to indicate relative importance of the features. Additional features and aspects are described and will become apparent to those of ordinary skill in the art upon reading the following detailed description and viewing the drawings that form a part hereof.

Certain aspects of the present disclosure generally relate to USB devices, and more particularly, to USB devices related to clock domains. A USB device is provided. The USB device may include at least one signal line adapted to carry signals in a first clock domain, the signals being received from a USB host. The clock operates a second clock domain. The periodic packet detection circuit is adapted to detect missing periodic packets from the received signal in the first clock domain. The device controller is adapted to correlate USB operations in the second clock domain with the first clock domain based on the periodic packet detection circuit detecting a missing periodic packet.

A method for operating a USB device is provided. The method comprises the following steps: providing signals in a first clock domain, the signals received from a USB host; detecting missing periodic packets from a signal received in a first clock domain; and correlating USB operations in the second clock domain with the first clock domain based on detecting lost periodic packets.

Another USB device is provided. The USB device includes at least one signal line adapted to carry UTMI or ULPI signaling. The USB controller is adapted to decode the packet identification in UTMI or ULPI signaling. A periodic packet detection circuit, separate from the USB controller, is adapted to decode the packet identification in UTMI or ULPI signaling.

A method for operating a USB device is provided. The method comprises the following steps: decoding the packet identification in the UTMI or ULPI signaling via a first decoding path; and decoding a second packet identification in the UTMI or ULPI signaling via a second decoding path, the second decoding path being independent of the first decoding path.