USB_ManageDeviceAddresses (SWI&55388) — Manages device addresses.
| R0 | Pointer to host controller structure. | ||||||||||||
| R1 | Pointer to device structure or zero | ||||||||||||
| R2 | Device number Table 1.1, “Constants used for Device Numbering” | ||||||||||||
| R3 |
| ||||||||||||
| R4 | Reserved. Must be set to zero. | ||||||||||||
| R5 | Reserved. Must be set to zero. |
| R0 | preserved |
| R1 | Error code Table A.1, “Error codes used by the USB system” |
| R2 | Depends on the behaviour control. At USB_DEVICE_ADDRESS_OP_CHANGE the old device address is returned, at USB_DEVICE_ADDRESS_OP_CLAIM the reserved device address is returned and at USB_DEVICE_ADDRESS_OP_RELEASE the released device address is returned. USB_DEVICE_AUTO_NUMBER will be returned if an error occurs. |
| R3, R4, R5 | Preserved |
References will be kept in every case.
In fact the SWI contains 3 different function which allows you to manage to device addresses for a given controller. The functions are also used internally by the USB module at USB_DeviceRegister/USB_DeviceDeregister.
At USB_DEVICE_ADDRESS_OP_CLAIM you must pass a reference to the device for which the new address is reserved. Normally this is done by USB_DeviceRegister and you will not use this function. The only usage for a normal program is to reserve an address for changing the device address. In this case you must pass a device reference zero. You can either reserve a given address or let the USB module determine an unused number for you if passing USB_DEVICE_AUTO_NUMBER.
With USB_DEVICE_ADDRESS_OP_CHANGE you can change the number of a device. Please note that all transactions belonging to this device (that means on all endpoints!) will be aborted during this process. You must reserve a new device number by using USB_DEVICE_ADDRESS_OP_CLAIM before. At USB_DEVICE_ADDRESS_OP_CHANGE you must pass the reference to the device together with the new number.
USB_DEVICE_ADDRESS_OP_RELEASE will normally be used automatically if USB_DeviceDeregister is called. It puts the address back into a list of unused devices. It can be used by normal programs together with a device reference of zero if an USB Standard address change request for which an address has been allocated by using USB_DEVICE_ADDRESS_OP_CLAIM before fails.
Normally changing of the device address from the default device address to a usual address will be done by the USB Hub module driver (using the calls described above) so you will never have to use this call by your own programs.