Low-Level API

If an application wishes to use a device for which no class driver is available, or the device does not adhere to a USB standard class, the low-level API can be used to directly communicate with the device and implement a custom USB client.

Any USB client must implement an attachment and detachment callback. It is used to inform the client of the attachment and detachment of USB devices. In the callback, the client can use Device Query functions to get information about the device. In particular, it can locate interfaces which it could use to handle the device. If such interfaces are found, Device Configuration functions can be used to take ownership of an interface. Pipe I/O functions can then be used to communicate with the device.

The source code of all class drivers is included with RTUSB-32 in directory Driver\Rtu32. It contains many examples for using RTUSB-32's low-level API.

Left Programming with RTUSB-32

Class Drivers

Right Attachment/Detachment Callbacks

Right Device Query

Right Device Configuration

Right Pipe I/O

Right Structure of a Passive USB Client

Right Structure of an Active USB Client

Down Using RTUSB-32 with Delphi