Datasheet

9166DS–AVR-01/12

AT32UC3C

Fix/Workaround

None.

3 In host mode, the disconnection during OUT transition is not supported

In USB host mode, a pipe can not work if the previous USB device disconnection has

occurred during a USB transfer.

Fix/Workaround

Reset the USBC (USBCON.USB=0 and =1) after a device disconnection (UHINT.DDISCI).

4 In USB host mode, entering suspend mode can fail

In USB host mode, entering suspend mode can fail when UHCON.SOFE=0 is done just

after a SOF reception (UHINT.HSOFI).

Fix/Workaround

Check that UHNUM.FLENHIGH is below 185 in Full speed and below 21 in Low speed

before clearing UHCON.SOFE.

5 In USB host mode, entering suspend mode for low speed device can fail when the

USB freeze (USBCON.FRZCLK=1) is done just after UHCON.SOFE=0.

Fix/Workaround

When entering suspend mode (UHCON.SOFE is cleared), check that USBFSM.DRDSTATE

is not equal to three before freezing the clock (USBCON.FRZCLK=1).

10.1.11 WDT

1 WDT Control Register does not have synchronization feedback

When writing to the Timeout Prescale Select (PSEL), Time Ban Prescale Select (TBAN),

Enable (EN), or WDT Mode (MODE) fieldss of the WDT Control Register (CTRL), a synchro-

nizer is started to propagate the values to the WDT clcok domain. This synchronization

takes a finite amount of time, but only the status of the synchronization of the EN bit is

reflected back to the user. Writing to the synchronized fields during synchronization can lead

to undefined behavior.

Fix/Workaround

-When writing to the affected fields, the user must ensure a wait corresponding to 2 clock

cycles of both the WDT peripheral bus clock and the selected WDT clock source.

-When doing writes that changes the EN bit, the EN bit can be read back until it reflects the

written value.