# Why two xHCI?

**URL:** https://forums.sifive.com/t/why-two-xhci/6733
**Category:** HiFive Premier P550
**Created:** [November 19, 2024, 6:57pm UTC](https://forums.sifive.com/t/why-two-xhci/6733 "2024-11-19T18:57:19Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![mason1920](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.sifive.com/mason1920/32/1701_2.png) [@mason1920](https://forums.sifive.com/u/mason1920)
#### Post date: [November 19, 2024, 6:57pm UTC](https://forums.sifive.com/t/why-two-xhci/6733/1 "2024-11-19T18:57:19Z")

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I see there’s usb0 and usb1 in the device tree. The eic7700x manual confirms with “the chip contains two identical usb”. Which controllers are in charge of what ports?

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### Author: ![Raza](https://avatars.discourse-cdn.com/v4/letter/r/82dd89/32.png) [@Raza](https://forums.sifive.com/u/Raza)
#### Post date: [November 20, 2024, 5:29am UTC](https://forums.sifive.com/t/why-two-xhci/6733/2 "2024-11-20T05:29:46Z")

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Do figure 4-1 and section 5-5 of “HiFive Premier P550 Getting Started Guide” answer your question?

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### Author: ![mason1920](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.sifive.com/mason1920/32/1701_2.png) [@mason1920](https://forums.sifive.com/u/mason1920)
#### Post date: [November 20, 2024, 5:25pm UTC](https://forums.sifive.com/t/why-two-xhci/6733/3 "2024-11-20T17:25:29Z")

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Yes it does, thank you.