Datasheet

251

7593L–AVR–09/12

AT90USB64/128

• the HWUPI interrupt is triggered in the Host mode (HOST set)

• the IDTI interrupt is triggered

• the VBUSTI interrupt is triggered

22.5.3 Freeze clock

The firmware has the ability to reduce the power consumption by setting the FRZCLK bit, which

freeze the clock of USB controller. When FRZCLK is set, it is still possible to access to the fol-

lowing registers:

• USBCON, USBSTA, USBINT

• UDCON (detach, ...)

•UDINT

•UDIEN

•UHCON

•UHINT

•UHIEN

Moreover, when FRZCLK is set, only the following interrupts may be triggered:

• WAKEUPI

•IDTI

•VBUSTI

•HWUPI

22.6 Speed control

22.6.1 Device mode

When the USB interface is configured in device mode, the speed selection (Full Speed or Low

Speed) depends on the UDP/UDM pull-up. The LSM bit in UDCON register allows to select an

internal pull up on UDM (Low Speed mode) or UDP (Full Speed mode) data lines.

Figure 22-14. Device mode speed selection.

DETACH

UDCON.0

UDP

UDM

LSM

UDCON.2

UCAP

USB

regulator