---
title: ReferenceMicroframe
framework: usbdriverkit
role: symbol
role_heading: Instance Method
path: usbdriverkit/iousbhostdevice/referencemicroframe
---

# ReferenceMicroframe

## Declaration

```occ
virtual kern_return_t ReferenceMicroframe(uint64_t *microframeNumber, uint64_t *theTime);
```

## Parameters

- `microframeNumber`: uint64_t pointer to be updated with the current frame number
- `theTime`: If not NULL, this will be updated with the system time assosiated with the returned microframe

## Return Value

Return Value KERN_SUCCESS is successful see IOReturn.h for error codes.

## Discussion

Discussion Return a recent microframe number of the USB controller. This method will return a recent microframe number of the USB controller with a timestamp captured near the microframe boundary. This is most useful for scheduling future isochronous requests.