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# referenceMicroframeWithTime:error:

```
- (uint64_t) referenceMicroframeWithTime:(IOUSBHostTime *) time error:(NSError **) error;
```

## Parameters

`time`

If not nil, this will be updated with system time associated with the microframe.

## Return Value

A recent microframe number. Returns 0 on failure, with NSError populated with the IOReturn error code.

## Discussion\abstract Return a recent microframe number of the USB controller
\discussion This method will return a recent microframe number of the USB controller.
This is most useful for scheduling future isochronous requests.

---

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