Difference between revisions of "USB"

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C1,C2: 0.1uF
 
C1,C2: 0.1uF
  
 +
(read warning above)
  
  

Revision as of 13:58, 4 April 2008

USBH_PWR1 Pull-up to 3.3 volts to enable USB port
USBH_PEN1
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. The pinouts you need 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 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


Examples

File:24-pin-usb-example.png

U1: LM3480

C1,C2: 0.1uF

(read warning above)


Related

Universal Serial Bus Revision 2.0 specification

Open HCI—Open Host controller Specification for USB


.