USB_MsgOp (SWI&55399)
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## Name

USB_MsgOp (SWI&55399) — Message operations

## On Entry

R0 |
Value | Definition | Description
--- | --- | ---
0 | USB_MSGOP_NONE |
1 | USB_MSGOP_REGISTER |
2 | USB_MSGOP_DEREGISTER |
3 | USB_MSGOP_FILTER |
4 | USB_MSGOP_FILTERALL |
R1 | Pointer to message handler
R2 | Parameter to message handler
R3 | Message class
R4 | 0 disable - 1 enable
R5 |

## On Exit

R0 | preserved
R1 | Error code Table A.1
R2, R3, R4, R5 | Preserved

## Use

## Related SWI's

USB_MsgSend (SWI&55398)

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USB_MsgSend (SWI&55398) | Home | USB_MiscOp (SWI&5539A)