USB 2.0
Datasheet
5.2USB251x Pin Descriptions (Grouped by Function)
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| Table 5.2 USB251x Pin Descriptions |
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| SYMBOL | TYPE | DESCRIPTION |
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| UPSTREAM USB 2.0 INTERFACES |
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| USBDM_UP | USB Data |
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| USBDP_UP |
| These pins connect to the upstream USB bus data signals (host, port, or |
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| upstream hub). |
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| VBUS_DET | I/O12 | Detect Upstream VBUS Power |
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| Detects state of Upstream VBUS power. The SMSC hub monitors |
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| VBUS_DET to determine when to assert the internal D+ |
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| signals a connect event. |
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| When designing a detachable hub, this pin should be connected to VBUS on |
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| the upstream port via a 2 to 1 voltage divider. |
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| For |
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| be connected to 3.3 V (typically VDD33). |
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| DOWNSTREAM USB 2.0 INTERFACES |
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| USBDP_DN[x:1]/ |
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| PRT_DIS_P[x:1] |
| These pins connect to the downstream USB peripheral devices attached to |
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| the hub’s port. To disable, pull up with a 10 K resistor to 3.3 V. |
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| USBDM_DN[x:1]/ |
| Downstream Port Disable Strap Option |
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| PRT_DIS_M[x:1] |
| If this strap is enabled by package and configuration settings (see Table 8.1, |
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| "Hub Configuration Options"), then this pin will be sampled at RESET_N |
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| negation to determine if the port is disabled. |
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| To disable a port, pull up both PRT_DIS_M[x:1] and PRT_DIS_P[x:1] pins |
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| corresponding to the port numbers. |
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| PRTPWR[x:1] / | O12 | USB Power Enable |
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| Enables power to USB peripheral devices downstream. |
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| When PRTPWR_POL pin is unavailable, the hub supports active high power |
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| controllers only. |
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| When PRTPWR_POL pin is available, the active signal level of the PRTPWR |
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| pins is determined by the power polarity strapping function of the |
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| PRTPWR_POL pin. |
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| BC_EN[x] | IPD | Battery Charging Strap Option |
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| *This feature is only available on USB251xB/Bi. |
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| If this strap is enabled by package and configuration settings, (see Table 8.1, |
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| "Hub Configuration Options"), this pin will be sampled at RESET_N negation |
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| to determine if ports [x:1] support the battery charging protocol (and thus the |
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| supporting external port power controllers) that would enable a device to draw |
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| the currents per the USB battery charging specification. |
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| BC_EN[x] = 1: Battery charging feature is supported for port x |
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| BC_EN[x] = 0: Battery charging feature is not supported for |
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| port x |
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Revision 1.0 |
| 22 | SMSC USB251x | ||
DATASHEET