Datasheet

Bit 5 – DNRSM Down Resume Interrupt Flag

This flag is cleared by writing a one to the flag.

This flag is set when the USB has sent a Down Resume and will generate an interrupt if INTENCLR/

SET.DRSM is one.

Writing a zero to this bit has no effect.

Bit 4 – WAKEUP Wake Up Interrupt Flag

This flag is cleared by writing a one.

This flag is set when:

l The host controller is in suspend mode (SOFE is zero) and an upstream resume from the device is

detected.

l The host controller is in suspend mode (SOFE is zero) and an device disconnection is detected.

l The host controller is in operational state (VBUSOK is one) and an device connection is detected.

In all cases it will generate an interrupt if INTENCLR/SET.WAKEUP is one.

Writing a zero to this bit has no effect.

Bit 3 – RST Bus Reset Interrupt Flag

This flag is cleared by writing a one to the flag.

This flag is set when a Bus “Reset” has been sent to the Device and will generate an interrupt if

INTENCLR/SET.RST is one.

Writing a zero to this bit has no effect.

Bit 2 – HSOF Host Start-of-Frame Interrupt Flag

This flag is cleared by writing a one to the flag.

This flag is set when a USB “Host Start-of-Frame” in Full Speed/High Speed or a keep-alive in Low

Speed has been sent (every 1 ms) and will generate an interrupt if INTENCLR/SET.HSOF is one.

The value of the FNUM register is updated.

Writing a zero to this bit has no effect.

SAM D21 Family

USB – Universal Serial Bus

Datasheet Complete

DS40001882D-page 867