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18 lines
941 B
Markdown
18 lines
941 B
Markdown
# Handling GET_DESCRIPTOR Configuration Requests
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When the host issues a GET_DESCRIPTOR *Configuration* request the device needs to respond with the requested configuration descriptor *plus* all the interface and endpoint descriptors associated to that configuration descriptor during the DATA stage.
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As a reminder, all GET_DESCRIPTOR request types are share the following properties:
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- `bmRequestType` is **0b10000000**
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- `bRequest` is **6** (i.e. the GET_DESCRIPTOR Request Code, defined in table 9-4 of the [USB specification][usb_spec])
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A GET_DESCRIPTOR *Configuration* request is determined the high byte of its `wValue` field:
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- The high byte of `wValue` is **2** (i.e. the `CONFIGURATION` descriptor type, defined in table 9-5 of the [USB specification][usb_spec])
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[usb_spec]: https://www.usb.org/document-library/usb-20-specification
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In the next sections, let's look into all the concepts required to respond to this request.
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