Method and apparatus for implementing general-purpose serial bus USB OTG

Abstract

The invention discloses a method which realizes the universal serial bus USB OTG and includes that the processor detects the principal- subordinate identification interface signal though the second GPIO and judges the level of the principal-subordinate identification interface signal; if the principal-subordinate identification interface signal is low level, the USB principle device controller is started; if the principal-subordinate identification interface signal is high level, the USB subordinate device controller is started; meanwhile, the invention also discloses a device which realizes the universal serial bus USB OTG; the device comprises a processor, a plurality of analog switches, a power module and a MINI_AB interface module; wherein, the processor includes a USB principle device controller, a USB subordinate device controller, four GPIO interfaces, two data interface signals, a power interface signal and a principal-subordinate identification interface signal. The method and the device which realize the universal serial bus USB OTG provide the client with a set of universal serial bus USB OTG solution which has the advantages of simple circuit, low cost, convenient application, wide application range and reliable performance.

Description

technical field [0001] The invention mainly relates to the field of computer data communication, in particular to a method and device for realizing the universal serial bus USB OTG. Background technique [0002] Universal Serial Bus (USB, Universal Serial Bus) OTG (On The Go) technology refers to a technology in which a device with a USB interface directly performs data communication without a computer. The identity directly communicates data with another set of specific peripheral devices. At the end of 2001, the USB Developer Forum released a supplementary specification of the USB2.0 protocol dedicated to the "removable interconnection" between USB peripheral devices, namely the USB OTG specification, which includes the following points: [0003] Support point-to-point communication between devices, especially for the case where the devices at both ends of the data communication support the USBOTG specification, a host circulation protocol HNP (HostNegotiation Protocol) t...

AI Technical Summary

Problems solved by technology

[0032] In summary, for the first device with USB OTG function, it separates the USB master and slave controllers from the USB forwarding circuit, and designs the USB forwarding circuit and the USB OTG controller into a controller chip. The scheme is more suitable for early digital processors or ASICs that are difficult to integrate forwarding circuits, and with the development of chip analog-digital hybrid technology, most of the processors currently used in PDA or mobile phone terminals have realized a complete USB host, The slave device controller circuit, that is, the USB controller and the USB forwarding circuit are integrated together. Therefore, due to the cumbersome control interface of the device, the high cost of two dedicated chips and the mismatch with the existing processor interface, etc., It has been unable to meet the needs of realizing USB OTG function based on the current mobile phone or PDA and other handheld device platforms

[0033] For the second device with USB OTG function, since the USB OTG control chip used therein has integrated the master and slave controller modules, a set of processor platforms with master and slave controllers will be wasted. Master and slave controllers, resulting in an increase in cost

In addition, since control and data access will occupy the asynchronous bus of the processor, it will cause bus contention between other asynchronous bus interface devices and USB device access, greatly affecting the performance of the system

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