AN672 View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

MFG CO.

AN672

PRECISION32™ SI32LIBRARY OVERVIEW

Silicon Laboratories 

AN672

11.7. si32UsbIoObject, si32UsbEndpointIoObject, and si32UsbDefaultEndpointIoObject

The si32UsbIoObject extends the si32IoObject by adding definitions and initialization of resources required

specifically to support USB I/O requests, including independent IoRequestPools, IoBufferPools, and

IoRequestQueues.

The si32UsbDefaultEndpointIoObject extends the si32UsbIoObject by implementing I/O operations specifically

using the USB control pipe protocol over the default endpoint (EP0). The si32UsbDefaultEndpointIoObject treats

transmit and receive operations as interdependent operations and enables support for SETUP packet detection

and notification. The si32UsbDefaultEndpointIoObject does not have any dependencies on the

si32UsbEndpointIoObject so that USB applications that require only the default endpoint can exclude the code and

memory overhead required to support unused endpoints.

si32UsbEndpointIoObject extends the si32UsbIoObject by adding definitions and the initialization of resources

required to support non-EP0 USB I/O Requests, including Bulk, Interrupt and Isochronous transfers. The

si32UsbEndpointIoObject requires use of both the SI32_USB_A_Type and SI32_USBEP_A_Type hardware

instances. Unlike the si32UsbDefaultEndpointIoObject, each direction of an si32UsbIoObject is designed to

operate completely independent of the other direction and for configuring the SI32_USBEP_A hardware on

demand, dynamically reconfiguring the endpoint control to reflect the run-time configuration.

Figure 23 shows the USB objects diagram.

si32IoObject

si32UsbIoObject

si32UsbEndpointIoObject

si32UsbDefaultEndpointIoObject

SI32_USBEP_A_Type

SI32_USB_A_Type

Figure 23. si32UsbIoObject, si32UsbEndpointIoOject, and si32UsbDefaultEndpointIoObject

Diagram

Rev. 0.1

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