USB_PipeClear (SWI&5538D)
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## Name

USB_PipeClear (SWI&5538D) — Aborts all requests for the specified pipe.

## On Entry

R0 | Pointer to pipe structure.
R1 |
Value | Definition | Description
--- | --- | ---
0 | USB_PIPE_CLEAR_NOCHANGE | Pipe state will be unaltered after clearing.
1 | USB_PIPE_CLEAR_ACTIVATE | Pipe will be set to active after clearing.
R2 | Reserved. Must be set to zero.

## On Exit

R0 | preserved
R1 | Error code Table A.1
R2 | Preserved

## Use

This call will abort all transcations on the specified pipe. The state of any active transactions is indetermiante and should not be relied upon to have completed successfuly. Transactions are terminated correctly with their waiting structures notified with the apropriate result.

Only a pipe in the opened or halted state may be cleared. If the pipe is in the halted state it may be changed to the active state by setting the apropriate flag in R1.

## Related SWI's

USB_PipeOpen (SWI&5538B)
USB_PipeClose (SWI&5538C)
USB_PipeHalt (SWI&5538E)

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