Difference between revisions of "USB"

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'''WARNING:''' This information could be yet inaccurate. '''TODO:''' D+/D- pull-down resistors (software?), termination resistors and capacitors for EMI suppresion, plus USBH_PEN1 and USBH_PWR1
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'''WARNING:''' This page is at this moment incomplete/inaccurate!
 +
 
 +
'''TODO:''' D+/D- pull-down resistors (software?), termination resistors and capacitors for EMI suppresion, ESD protection, USBH_PEN1 and USBH_PWR1 (power switch)
  
  
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[[image:24-pin-usb-example.png]]
 
[[image:24-pin-usb-example.png]]
  
U1: LM3480
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U1: LM3480 3.3V Voltage regulator
  
C1,C2: 0.1uF
+
C1,C2: 0.1uF Capacitors
  
(*read warning above)
+
(*this example may not work, read warning above)
  
  

Revision as of 17:20, 4 April 2008

USBH_PWR1 Over-current indicator (input, active low)
USBH_PEN1 Power enable USB port (output)
USBH_P1 USB port USB D+
USBH_N1 USB D-
V_BATT USB VBUS
GND USB DGND


The 24-pin flex ribbon connector has USB port 1 on it. USB port 2 is on the 60-pin Hirose connector

The pinouts you need for USB port 1 are:


  • V_BATT (pin 24) - USB power
  • USBH_N1 (pin 18) - USB D-
  • USBH_P1 (pin 17) - USB D+
  • GND (pin 8) - USB Ground


In addition, you need to pull USBH_PWR1 (pin 20) up to 3.3 volts to enable the port. You need to provide a stable 3.3 volt supply, which is fairly simple to do by adding a small SOT23 package voltage regulator (like the LM3480), with the power input coming from V_BATT (pin 24) and the output going to USBH_PWR1 (pin 20).


WARNING: This page is at this moment incomplete/inaccurate!

TODO: D+/D- pull-down resistors (software?), termination resistors and capacitors for EMI suppresion, ESD protection, USBH_PEN1 and USBH_PWR1 (power switch)


Examples

File:24-pin-usb-example.png

U1: LM3480 3.3V Voltage regulator

C1,C2: 0.1uF Capacitors

(*this example may not work, read warning above)


Related

PXA270 Design Guide, P. 202

Universal Serial Bus Revision 2.0 specification

Open HCI—Open Host controller Specification for USB

Implementing the Physical Layer in a USB 2.0 Compliant System, AN-5052, Fairchild Semiconductor


.