Difference between revisions of "USB"
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{| border="1" cellpadding="5" cellspacing="0" | {| border="1" cellpadding="5" cellspacing="0" | ||
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| − | | style="width:100px;background:limegreen;" | USBH_PWR1 || colspan="2" | Over-current indicator (input, active low) | + | | style="width:100px;background:limegreen;" | USBH_PWR1 || colspan="2" | Over-current fault indicator (input, active low) |
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| style="background:limegreen;" | USBH_PEN1 || colspan="2" | Power enable USB port (output) | | style="background:limegreen;" | USBH_PEN1 || colspan="2" | Power enable USB port (output) | ||
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| − | The [[24pin_connector|24-pin flex ribbon]] connector has '''USB port 1''' on it. '''USB port 2''' is on the [[60pin_connector|60-pin Hirose connector]] | + | The [[24pin_connector|24-pin flex ribbon]] connector has '''USB Host port 1''' on it. '''USB Host port 2''' is on the [[60pin_connector|60-pin Hirose connector]] |
| − | The pinouts you need for USB port 1 are: | + | The pinouts you need for USB Host port 1 are: |
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| − | 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 [http://www.national.com/mpf/LM/LM3480.html LM3480]), with the power input coming from V_BATT (pin 24) and the output going to USBH_PWR1 (pin 20). | + | In addition, you need to pull USBH_PWR1 (pin 20) up to 3.3 volts to enable the port (this is a hack, USBH_PEN1 and USBH_PWR1 should be used by a power switch IC -for example [http://www.ti.com/lit/gpn/tps2041b TPS2041B]- to power the USB port and monitor over-current/short-circuit conditions). 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 [http://www.national.com/mpf/LM/LM3480.html LM3480]), with the power input coming from V_BATT (pin 24) and the output going to USBH_PWR1 (pin 20). |
| − | + | USBH_N1 and USBH_P1 (D-/D+) require 15K pull-down resistors each, 10-25 ohm series resistors and 68-75pF capacitors. ESD protection/transient suppression is recommended (example: [http://www.ti.com/lit/gpn/sn65220 SN65220 single port transient suppressor]). | |
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| + | Refer to the PXA270 Design Guide, P. 202 (link on the bottom of this page) for more information. | ||
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| − | + | == Examples == | |
[[image:24pin-connector-usb-example.png]] | [[image:24pin-connector-usb-example.png]] | ||
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| + | USB Host example without ESD and over-current protections (not fully USB-compliant) | ||
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[http://www.fairchildsemi.com/an/AN/AN-5052.pdf Implementing the Physical Layer in a USB 2.0 Compliant System, AN-5052, Fairchild Semiconductor] | [http://www.fairchildsemi.com/an/AN/AN-5052.pdf Implementing the Physical Layer in a USB 2.0 Compliant System, AN-5052, Fairchild Semiconductor] | ||
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Revision as of 17:59, 7 April 2008
| USBH_PWR1 | Over-current fault 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 Host port 1 on it. USB Host port 2 is on the 60-pin Hirose connector
The pinouts you need for USB Host 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 (this is a hack, USBH_PEN1 and USBH_PWR1 should be used by a power switch IC -for example TPS2041B- to power the USB port and monitor over-current/short-circuit conditions). 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).
USBH_N1 and USBH_P1 (D-/D+) require 15K pull-down resistors each, 10-25 ohm series resistors and 68-75pF capacitors. ESD protection/transient suppression is recommended (example: SN65220 single port transient suppressor).
Refer to the PXA270 Design Guide, P. 202 (link on the bottom of this page) for more information.
Examples
File:24pin-connector-usb-example.png
USB Host example without ESD and over-current protections (not fully USB-compliant)
Related
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
.
