Patent Application
20120290761
The disclosure relates to Universal Serial Bus (USB) conversion, and more particularly to a USB converter, and related method.
Universal Serial Bus (USB) specification 2.0 has transfer speed of 480 Mbps, and maximum output current of 500 mA. In many cases, the 500 mA of current supplied by a single USB 2.0 port is insufficient for powering peripheral devices, such as external hard disk drives (HDDs). One solution is to use a Y-cable to draw power from two USB ports, but this takes up an extra USB port. Another solution is an external alternating current (AC) adapter, but this adds extra weight to the device, making the peripheral cumbersome, and also increases the chance that the user will forget or lose the AC adapter, rendering the peripheral device useless until a replacement is found.
Universal Serial Bus (USB) specification 3.0 improves over USB 2.0 with transfer speed increased from 480 Mbps to 5 Gbps, output current increased from 500 mA to 900 mA, and more available power management modes. However, USB 2.0 devices are still prevalent, and pin configurations are different for USB 2.0 devices and USB 3.0 devices. Thus, when a USB device is connected to a USB 3.0 host, a handshake process must be performed to identify the USB device as either a USB 2.0 device or a USB 3.0 device. The handshake process is slow, which wastes time, and frustrates the user. Further, although USB 3.0 devices are compatible with USB 2.0 devices, when a USB 3.0 device is connected to a USB 2.0 device, the devices communicate in USB 2.0 mode, such that the higher output current and faster transfer speed of USB 3.0 cannot be used.
According to an embodiment, a Universal Serial Bus (USB) converter used in a USB system comprises at least one USB package processing unit and a processor. Each USB package processing unit is for receiving input packets of a first protocol from a corresponding first USB device, converting the input packets into output packets of a second protocol, and outputting the output packets to a second USB device. The processor is for selectively placing each USB package processing unit of the at least one USB package processing unit in a standby mode according to a detection signal indicating the first USB device uses the first protocol. The detection signal is generated according to electrical state of at least one pin of the USB system coupled to a corresponding pin of the first USB device.
According to an embodiment, a Universal Serial Bus (USB) connector system comprises at least one USB port for receiving a first USB signal according to a first protocol or a second USB signal according to a second protocol from a first USB device, a controller coupled to a first set of pins of the at least one USB port for receiving the first USB signal, and a converter coupled to a second set of pins of the at least one USB port and to the controller for converting the second USB signal to a third USB signal according to the first protocol, then transmitting the third USB signal to the controller.
According to an embodiment, a method of operating a Universal Serial Bus (USB) converter of a USB system comprises a USB device plugging into a USB port of the USB system, the USB converter detecting electrical state of a pin of the USB port to generate a detection signal, determining whether the USB device is a USB 2.0 device or a USB 3.0 device according to the detection signal, and the USB converter entering an active mode when the detection signal indicates that the USB device is a USB 2.0 device.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Please refer to
The USB converter 120 may be configured to perform conversion from USB 2.0 to USB 3.0, and from USB 3.0 to USB 2.0, and includes converter data terminals D+, D− coupled to the USB 2.0 data pins D+, D−, converter transmit terminals C_TX+, C_TX− coupled to the host receive terminals H_RX+, H_RX−, and converter receive terminals C_RX+, C_RX− coupled to the host transmit terminals H_TX+, H_TX−. As shown in
From the above description, it can be seen that the USB system 10 is configured in such a way that both USB 2.0 devices and USB 3.0 devices are seen by the USB 3.0 controller 100 as USB 3.0 devices when plugged into the system, and the USB 3.0 controller also communicates with plugged in USB devices (USB 2.0 or USB 3.0) according to USB 3.0 protocols. Thus, in addition to being able to provide up to 900 mA of current to both USB 2.0 and 3.0 devices, the USB 3.0 controller 100 can also employ more power management modes.
The USB converter 120 may further comprise a general purpose input/output (GPIO) terminal coupled to the USB 3.0 ground pin GND_DRAIN of the USB port 110 for detecting electrical state thereof, for example voltage level thereof, then determining whether the USB device is a USB 2.0 device or a USB 3.0 device and to enter an active mode or a standby mode. The USB 3.0 ground pin GND_DRAIN of the USB port 110 as well as the GPIO terminal are both grounded when a USB 3.0 device is connected to the USB port 110 due to being coupled to the GND_DRAIN pin of the USB 3.0 device, or both floating when a USB 2.0 device is connected to the USB port 110 due to there being no signal received from the GND_DRAIN pin of the USB port 110. The USB 3.0 ground pin GND_DRAIN of the USB port 110 may be initially set at a high voltage level through the GPIO terminal to aid in identification of the grounded/floating state. When a USB 2.0 device is plugged into the USB system 10, the USB 3.0 ground pin GND_DRAIN of the USB port 110 is floating, so the high voltage level remains, and the USB converter 120 operates in the active mode (components of the USB converter 120 related to performing conversion are turned on), and performs conversion to and from USB 3.0 between the USB controller 100 and the USB 2.0 device, so that the USB controller 100 may interface properly with the USB 2.0 device according to the USB 3.0 protocol. When a USB 3.0 device is plugged into the USB system 10, the USB 3.0 ground pin GND_DRAIN of the USB port 110 is grounded, so the voltage level is dropped, and the USB converter 120 enters the standby mode (components of the USB converter 120 related to performing conversion are turned off), which saves power, and the USB controller 100 interacts directly with the USB 3.0 device through coupling with the USB port 110, as shown in
Although
Please refer to
In the above configuration, the USB converter 120 detects the electrical state of the USB 3.0 ground pin GND_DRAIN of the USB port 110 to determine whether to enter the active mode or the standby mode. In another embodiment where the USB converter 120 optionally does not include the GPIO terminal 127, the USB converter 120 may detect voltage level of either or both of the USB 2.0 data pins D+, D− to determine whether to enter the active mode or the standby mode. For example, when a USB 3.0 device is plugged into the USB port 110, the data pins D+, D− are floating, so the USB converter 120 enters the standby mode. When a USB 2.0 device is plugged into the USB port 110, the data pins D+, D− are non-floating, and the voltage level of the data pins D+, D− is either high or low, so the USB converter 120 enters an active mode. Detection of D+, D− pin electrical state may be performed during a handshake, and the electrical states of the D+, D− pins can be determined immediately based on whether or not the D+, D− pins are carrying a signal. When a USB 3.0 device is plugged in, the D+, D− pins are considered to not be carrying a signal. Detection of a sufficiently constant (sufficiently unchanging over a period of time) voltage level on the D+, D− pins is considered “not carrying a signal”. When a USB 2.0 device is plugged in, the D+, D− pins are considered to be carrying a signal. Detection of high and low voltage levels on the D+, D− pins is considered “carrying a signal”. Changes in the voltage levels on the D+, D− pins may be detected over a period of time, e.g. a few clock cycles according to the USB 2.0 specification. For example, a predetermined number of bits of a known handshake sequence may be identified to determine that the connected USB device is a USB 2.0 device.
In another embodiment, the USB converter 120 may be coupled to any, some, or all of the USB 3.0 transmit/receive pins SS_TX+, SS_TX−, SS_RX+, SS_RX−, and may detect electrical states of any, some, or all of the USB 3.0 transmit/receive pins SS_TX+, SS_TX−, SS_RX+, SS_RX− to determine whether to enter the active mode or the standby mode. In another embodiment, the USB converter 120 may detect electrical states of either or both of the USB 2.0 power/ground pins VBUS, GND to determine whether to enter the active mode or the standby mode.
Any combination or alteration of the above embodiments may also be utilized, e.g. detecting voltage levels of both the USB 3.0 ground pin GND_DRAIN and the USB 2.0 ground pin GND. Further, such detection is not limited to the USB converter 120, but may also be performed by the USB 3.0 controller 100. For example, the USB 3.0 controller 100 may detect signals on any, some, or all of the USB 3.0 transmit/receive pins SS_TX+, SS_TX−, SS_RX+, SS_RX− coupled thereto, and send a signal to the USB converter 120 indicating whether the USB device is a USB 2.0 device or a USB 3.0 device for the USB converter 120 determining to enter the active mode or the standby mode.
Please refer to
Step 300: A USB device is plugged into a USB port of the USB system;
Step 302: A USB converter coupled to the USB port of the USB system detects electrical state of at least one USB pin of the USB port to determine the USB device is either a USB 2.0 or a USB 3.0 device;
Step 304: If the USB device is a USB 3.0 device, go to step 306; if the USB device is a USB 2.0 device, go to step 308;
Step 306: The USB converter enters a standby mode; go to step 312;
Step 308: The USB converter enters an active mode;
Step 310: The USB converter converts USB 2.0 signals to USB 3.0 signals, and USB 3.0 signals to USB 2.0 signals; and
Step 312: A USB controller of the USB system communicates with the USB device according to USB 3.0 protocols.
Initially, a USB 2.0 device or a USB 3.0 device is plugged into the USB port (Step 300). Upon the USB device being plugged in, the USB converter detects electrical state (e.g. voltage, current, floating, non-floating, carrying a signal, not carrying a signal) of one or more pins of the USB port (Step 302), as described above. Based on the electrical state detected by the USB converter, the USB converter enters the standby mode if the USB device is a USB 3.0 device (Step 306). If the USB device is a USB 2.0 device, the USB converter enters (or remains in) the active mode (Step 308).
Please refer to
The USB hub controller 400 further comprises a USB 3.0 US port transceiver 402 coupled to the US port 430. The USB hub controller 400 may further comprise at least a router/aggregator engine 403, a power management engine 404, and a control/status register 405. The router/aggregator engine 403 is coupled to the at least two USB 3.0 DS port transceivers 401_1-401_N, and to the USB 3.0 US port transceiver 402 for directing flow of packets between the at least two USB 3.0 DS port transceivers 401_1-401_N and the USB 3.0 US port transceiver 402. The power management engine 404 controls various power management modes of the USB host controller 400. The control/status register 405 controls behavior of the USB host controller 400, and also provides status information of the USB host controller 400. The USB 3.0 US port transceiver 402 is coupled to the US port 430 for communicating with the US port 430 in USB 3.0 mode.
The USB converter 420 comprises a plurality of converter units similar to the USB converter 120. The USB converter 420 comprises at least two input terminals 421_1-421_N, each input terminal coupled to a corresponding DS port of the at least two DS ports 410_1-410_N. The USB converter 420 further comprises at least two output terminals 422_1-422_N, each output terminal coupled to a corresponding DS port transceiver of at least two USB 3.0 DS port transceivers 401_1-401_N of the USB hub controller 400. The USB converter 420 may further comprise at least two corresponding GPIO terminals GPIO_1-GPIO_N. In the USB converter 420, each GPIO terminal GPIO_1-GPIO_N is part of a corresponding converter unit, and is used to detect electrical state of one or more pins of each DS port 410_1-410_N coupled to the corresponding USB device 440_1-440_N. Operation of each converter unit is the same as that of the USB converter 120. Each converter unit is capable of entering a standby mode or an active mode independently of other converter units in the USB converter 420 to provide conversion from USB 2.0 to USB 3.0 and vice versa. For each USB 3.0 device connected to the USB system 40, the corresponding converter unit of the USB converter 420 operates in the standby mode, and for each USB 2.0 device connected to the USB system 40, the corresponding converter unit of the USB converter 420 operates in the active mode. For example, as shown in
In the USB system 40, the USB hub can use each converter unit of the USB converter 420 to couple to the D+, D− pins of each connected USB device to determine whether the USB device is a USB 2.0 device or a USB 3.0 device according to the electrical state of the D+, D− pins of the DS ports 410_1-410_N, or include GPIO terminals coupled to the GND_DRAIN pins of each DS port 410_1-410_N to determine whether the USB device is a USB 2.0 device or a USB 3.0 device. The GPIO terminals provide immediate detection, and do not rely on the handshake process, and identification can be performed more directly and rapidly. Thus, if the USB system is realized as a USB 3.0 hub, the system can convert all USB 2.0 signals of all connected USB 2.0 devices to USB 3.0 signals for communication with the USB 3.0 host, and thereby provide higher speed and more power, as well as more power management options, when interacting with the USB 2.0 device.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
