USBLib_SetURB (SWI &56340)
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## Name

USBLib_SetURB (SWI &56340) — Sets values in a URB

## On Entry

R0 | Pointer to URB
R1 | bits to flag item to set
0 = number of bytes of used data
1 = pointer to the data
2 = total size
3-31 = reserved and should be 0
R2 | used size (only used if bit 0 is set)
R3 | pointer to data (only used if bit 1 is set)
R4 | total size (only used if bit 2 is set)

## On Exit

R0 - R4 | Preserved

## Use

This call allows a driver to change fields in a URB without a driver directly accessing the URB structure. Its main use is to change the used size parameter to vary the amount of data sent in a transaction.

### Note

The total size parameter must only be used if the URB is pointing to external data.

## Related SWIs

USBLib_URBInfo (SWI &56340)

## Related Information

Chapter 6

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