usb 1_1 for usb otg implementation - patent 7193442.htm

usb softconnection configration

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<DIV class=disp_elm_text>Texas Instruments Incorporated (Dallas, TX, US) 
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<DIV class=disp_elm_text><A 
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<DIV class=disp_elm_text>326/102, 710/105 </DIV></DIV><!--	International Classes  -->
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<DIV class=disp_elm_text><I><B>H03K19/0175</B></I>; <I><B>G06F13/42</B></I>; 
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<DIV class=disp_elm_text>326/82, 710/105, 710/315, 710/9, 710/313, 710/14, 
326/102, 710/305, 710/311 </DIV></DIV><!--	US Patent References  -->
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<TABLE class=patent_detail__table cellSpacing=0 cellPadding=0>
  <TBODY>
  <TR>
    <TD><A href="http://www.freepatentsonline.com/7000057.html">7000057</A></TD>
    <TD>Method and apparatus for adding OTG dual role device capability to a 
      USB peripheral</TD>
    <TD>February, 2006</TD>
    <TD>Novell et al.</TD>
    <TD>710/306</TD></TR>
  <TR>
    <TD><A 
      href="http://www.freepatentsonline.com/y2003/0204652.html">20030204652</A></TD>
    <TD>Data transfer control device, electronic equipment and data transfer 
      control method</TD>
    <TD>October, 2003</TD>
    <TD>Saito et al.</TD>
    <TD>710/33</TD></TR>
  <TR>
    <TD><A 
      href="http://www.freepatentsonline.com/y2004/0133820.html">20040133820</A></TD>
    <TD>Interfact circuit</TD>
    <TD>July, 2004</TD>
    <TD>Tanabe et al.</TD>
    <TD>713/600</TD></TR>
  <TR>
    <TD><A 
      href="http://www.freepatentsonline.com/y2006/0045112.html">20060045112</A></TD>
    <TD>Device operable as a host</TD>
    <TD>March, 2006</TD>
    <TD>Laiho</TD>
    <TD>370/419</TD></TR>
  <TR>
    <TD><A 
      href="http://www.freepatentsonline.com/y2006/0075152.html">20060075152</A></TD>
    <TD>USB attach detection for USB 1.1 and USB OTG devices</TD>
    <TD>April, 2006</TD>
    <TD>Zhu</TD>
    <TD>710/15</TD></TR></TBODY></TABLE></DIV></DIV><!--	Foreign Patent References:  --><!--		Other References  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Other References:</DIV>
<DIV class=disp_elm_text>“USB On-The-Go Basics”. Application Note 1822. Maxim 
IC. Dallas Semiconductor. Dec. 20, 2002, <HTTP: an1822 www.maxim-ic.com>. 
<BR>“Power Supply IC S1FF84100 Technical Manual”. Seiko Epson Corporation. Mar. 
2004. Document Code 404896200. <BR>“Microsoft Press Computer Dictionary”. Second 
Edition, Microsoft Press. 1994. pp. 261, 307, and 308. <BR>“USB On-The Go”. USB 
Implementers Forum, Inc. Online Jun. 6, 2002. Retrieved from Internet Jun. 15, 
2006. <HTTP: onthego developers www.usb.org http: 20020606022045 web 
web.archive.org />. <BR>“May 2001 Conference Presentations”. USB Implementers 
Forum, Inc. Retrieved from Internet Jun. 21, 2006. <HTTP: developers www.usb.org 
pres0501 presentations />. <BR>“On-The-Go Supplement to the USB 2.0 
Specification”. Revision 1.0. Dec. 18, 2001. <BR>“SL811HS OTG Application Note”. 
Cypress Semiconductor Corporation. Dec. 17, 2001. <BR>Koeman, Kosta. 
“Understanding USB On-The-Go”. EDN Magazine. Nov. 22, 2001. pp. 79-80 and 82. 
<BR>Yarra, Srinivas. “USB OTG software frees dual-role handheld devices”. EDN 
Magazine. May 16, 2002. pp. 83-84 and 86-88. <BR>“USB On-The-Go: A Tutorial”. 
Philips Semiconductors. Jan. 2002. Document Order No. 9397 750 09316. <BR>Tija, 
Jerome. “High-Speed Detection Handshake Considerations”. May 2001 Conference 
Presentation. May 9, 2001. <BR>Koeman, Kosta. “USB On-The-Go”. May 2001 
Conference Presentation. May 9. 2001. <BR>“USB On-The-Go Implementation”. 
On-The-Go Training Seminar Presentation. London, UK Feb. 26, 2002. <BR>“USB 
On-The-Go Electrical”. On-The-Go Training Seminar Presentation. London, UK Feb. 
26, 2002. <BR></DIV></DIV><!--	Primary Examiner  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Primary Examiner:</DIV>
<DIV class=disp_elm_text>Auve, Glenn A. </DIV></DIV><!--	Assistant Examiner  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Assistant Examiner:</DIV>
<DIV class=disp_elm_text>Cleary, Thomas J. </DIV></DIV><!--	Attorney, Agent or Firm  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Attorney, Agent or Firm:</DIV>
<DIV class=disp_elm_text>Marshall Jr., Robert D. <BR>Brady, James W. <BR>Telecky 
Jr., Frederick J. <BR></DIV></DIV><!--		Parent Case Data  --><!--	Claims  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Claims:</DIV>
<DIV class=disp_elm_text>What is claimed is:<BR clear=all><BR clear=all>1. An 
apparatus for a USB 1.1 device including a microcontroller for implementing USB 
OTG functions comprising: a Vbus pulsing detect circuit controlled by the 
microcontroller including a PMOS transistor (<B>506</B>) having a source 
connected to a power supply, a drain, and a gate connected to a charge-discharge 
control output of the microcontroller (<B>500</B>), a first resistor 
(<B>504</B>) connected between the source and gate of said PMOS transistor 
(<B>506</B>), a capacitor (<B>512</B>) connected between said drain of said PMOS 
transistor (<B>506</B>) and ground, a second resistor (<B>507</B>) having a 
first terminal connected to said drain of said PMOS transistor (<B>506</B>), and 
a second terminal, an NMOS transistor (<B>508</B>) having a source connected to 
said second terminal of said second resistor (<B>507</B>), a drain connected to 
ground, and a gate, a third resistor (<B>505</B>) connected between the 
charge-discharge control output of the microcontroller (<B>500</B>) and said 
gate of said NMOS transistor (<B>508</B>), a fourth resistor (<B>509</B>) 
connected between said gate of said NMOS transistor (<B>508</B>) and ground, and 
a comparator (<B>511</B>) having a first input connected to said drain of said 
PMOS transistor (<B>506</B>), a second input receiving the Vbus (<B>501</B>), 
and an output (<B>503</B>) connected to a Vbus detect input of the 
microcontroller; said microcontroller programmed to correlate a time between 
sending a signal on the charge-discharge control output of the microcontroller 
(<B>500</B>) to turn said NMOS transistor (<B>508</B>) ON and detection of 
tripping of said comparator (<B>511</B>) to a voltage on the Vbus (<B>501</B>) 
corresponding to a discharge time determined by a capacitance of said capacitor 
(<B>512</B>) and a resistance of said second resistor (<B>507</B>); a Vbus 
pulsing circuit controlled by the microcontroller; and a data line pull down 
detect circuit controlled by the microcontroller. <BR clear=all><BR clear=all>2. 
An apparatus for a USB 1.1 device including a microcontroller for implementing 
USB OTG functions comprising: a Vbus pulsing detect circuit controlled by the 
microcontroller; a Vbus pulsing circuit controlled by the microcontroller 
including a first resistor (<B>603</B>) having a first terminal connected to a 
voltage source (<B>610</B>) and a second terminal, an NMOS transistor 
(<B>604</B>) having a source connected to said second terminal of said first 
resistor, a drain connected to the Vbus (<B>606</B>), and a gate connected to a 
Vbus pulsing control output of the microcontroller (<B>600</B>), a capacitor 
(<B>605</B>) connected between said drain of said NMOS transistor and ground, a 
second resistor (<B>601</B>) connected between said Vbus pulsing control output 
of the microcontroller and said gate of said NMOS transistor, and a third 
resistor (<B>602</B>) connected between said gate and said drain of said NMOS 
transistor; and said microcontroller programmed to provide a low signal on said 
Vbus pulsing control output of the microcontroller (<B>600</B>) to turn said 
NMOS transistor (<B>604</B>) OFF permitting said capacitor (<B>605</B>) to 
discharge via said second resistor (<B>601</B>) and said third resistor 
(<B>602</B>) thereby pulsing the Vbus (<B>606</B>); a data line pull down detect 
circuit controlled by the microcontroller. <BR clear=all><BR 
clear=all></DIV></DIV><!--	Description  -->
<DIV class=disp_doc2>
<DIV class=disp_elm_title>Description:</DIV>
<DIV class=disp_elm_text><?BRFSUM description="Brief Summary" end="lead"?>
<H1>TECHNICAL FIELD OF THE INVENTION </H1>
<P>The technical field of this invention is retrofit circuits enabling a USB 1.1 
device to operate as a USB OTG device. </P>
<H1>BACKGROUND OF THE INVENTION </H1>
<P>Universal Serial Bus (USB) ports have been employed widely to connect 
peripheral devices to computers. Typical peripheral connections connected 
through USB are Printers, scanners, zip drives, digital cameras, mice, 
joysticks, modems, speakers, telephones, video phones and network connections. 
</P>
<P>Almost all peripheral devices now come in a USB version. The Universal Serial 
Bus allows for the connection of up to 128 devices to a computer. Upon 
connection of a new device the operating system auto-detects it and requests 
driver input. If the device has already been installed, the computer activates 
it and starts communication with it. </P>
<P>FIG. 1 illustrates a conventional USB 1.1 master-slave system <B>100 
</B>connected to a USB 1.1 slave only device <B>107 </B>. The USB master-slave 
system <B>100 </B>includes a USB 1.1 device <B>101 </B>, a USB 1.1 host <B>102 
</B>and a microcontroller <B>103 </B>that provides control of the device <B>101 
</B>and host <B>102 </B>as well as USB 1.1 protocol communications capability 
with USB 1.1 device <B>107 </B>through USB 1.1 connectors <B>104 </B>and <B>106 
</B>via USB 1.1 cable <B>105 </B>. </P>
<P>Many USB devices come with their own cable. The cable either has an A 
connection or the device has a socket that accepts a USB B connector. The USB 
standard uses A and B connectors to avoid confusion. A connectors are connected 
to host default functions. B connectors are connected to device default 
functions. </P>
<P>Using different connectors on the upstream and downstream end avoids any 
possible confusion and any USB device having either A or B cabling will function 
properly. The Universal Serial Bus has the following features. The computer acts 
as the host. Up to 127devices can connect to the host either directly or via a 
USB hub. Individual USB cables can run as long as 5 meters. Using a hub, devices 
can be up to 30 meters or about six cable lengths away from the host. A USB 1.1 
bus has a maximum data rate of 12 megabits per second; A USB 2.0 bus has a 
maximum data rate of 480 megabits per second. A USB cable has two wires for 
power (+5 volts and ground) and a twisted pair of wires carrying data in 
differential form. The computer can supply up to 500 milliamps of power at 5 
volts on the power wires. Low-power devices, such as a mouse, can draw their 
power directly from the bus. High-power devices such as printers must have their 
own power supplies and draw minimal power from the bus. Hubs can have their own 
power supplies to provide power to devices connected to the hub. USB devices are 
hot-swappable because the user can plug them into the bus and unplug them any 
time. Many USB devices can be put to sleep by the host computer when the 
computer enters a power-saving mode. </P>
<P>Slave devices connected to a USB port rely on the USB host and its cable to 
supply power and data. When the host powers up, it queries all of the devices 
connected to the bus and assigns each an address. This process is called 
enumeration. Devices are enumerated when they connect to the bus. The host finds 
out from each device what type of data transfer it wishes to perform: </P>
<P>1. Interrupt—A device like a mouse or a keyboard, which will be sending very 
little data, would choose the interrupt mode. </P>
<P>2. Bulk—A device like a printer, which receives data in one big packet, uses 
the bulk transfer mode. A block of data is sent to the printer (in 64-byte 
segments) and verified to make sure it is correct. </P>
<P>3. Isochronous—a streaming device such as a speaker uses the isochronous 
mode. Data streams between the device and the host in real-time and there is no 
error correction. The host can also send commands or query parameters with 
control packets. </P>
<P>The Universal Serial Bus divides the available bandwidth into frames and the 
host controls the frames. For USB 1.1 frames contain 1,500 bytes (12,000 bits) 
and a new frame starts every millisecond. During a one second interval of time 
12 megabits of data may be transmitted. For USB 2.0 the data rate is forty times 
higher and a new frame starts every microsecond. During a one second interval of 
time 480 megabits of data may be transmitted. USB specifications allow interrupt 
devices to have a portion of the frames so they are guaranteed the bandwidth 
they need. Bulk data and control transfers use whatever space is left. </P>
<P>The standard for USB version 2.0 was released in April 2000 and serves as an 
upgrade for USB 1.1. USB 2.0 (High-speed USB) provides additional bandwidth for 
multimedia and storage applications. To allow a smooth transition for both 
consumers and manufacturers, USB 2.0 has full forward and backward compatibility 
with original USB devices and works with cables and connectors made for earlier 
versions of USB. </P>
<P>Supporting three speed modes (1.5, 12 and 480 megabits per second), USB 2.0 
supports low-bandwidth devices such as keyboards and mice, as well as 
high-bandwidth devices like high-resolution Webcams, scanners, printers and 
high-capacity storage systems. The deployment of USB 2.0 has allowed the PC 
industry to forge ahead with the development of next-generation PC peripherals