Atmel Xplained Evaluation Board AT32UC3A3-XPLD AT32UC3A3-XPLD データシート

32072H–AVR32–10/2012

For instance, if NBTRANS is three (three transactions per micro-frame), if only the first IN token
(among 3) is well received by the USBB, then the two last banks will be discarded.

This error exists only for isochronous OUT endpoints. It set the CRC Error Interrupt (CRCERRI)
bit in UESTAn, what triggers an EPnINT interrupt if the CRC Error Interrupt Enable (CRCERRE)
bit is one.

A CRC error can occur during OUT stage if the USBB detects a corrupted received packet. The
OUT packet is stored in the bank as if no CRC error had occurred (RXOUTI is set).

See the structure of the USB device interrupt system on 

There are two kinds of device interrupts: processing, i.e. their generation is part of the normal
processing, and exception, i.e. errors (not related to CPU exceptions).

The processing device global interrupts are:

• The Suspend (SUSP) interrupt 

• The Start of Frame (SOF) interrupt with no frame number CRC error (the Frame Number 

CRC Error (FNCERR) bit in the Device Frame Number (UDFNUM) register is zero)

• The Micro Start of Frame (MSOF) interrupt with no CRC error.

• The End of Reset (EORST) interrupt 

• The Wake-Up (WAKEUP) interrupt 

• The End of Resume (EORSM) interrupt 

• The Upstream Resume (UPRSM) interrupt 

• The Endpoint n (EPnINT) interrupt 

• The DMA Channel n (DMAnINT) interrupt 

The exception device global interrupts are:

• The Start of Frame (SOF) interrupt with a frame number CRC error (FNCERR is one)

• The Micro Start of Frame (MSOF) interrupt with a CRC error

The processing device endpoint interrupts are:

• The Transmitted IN Data Interrupt (TXINI)

• The Received OUT Data Interrupt (RXOUTI)

• The Received SETUP Interrupt (RXSTPI)

• The Short Packet (SHORTPACKET) interrupt

• The Number of Busy Banks (NBUSYBK) interrupt 

• The Received OUT isochronous Multiple Data Interrupt (MDATAI)

• The Received OUT isochronous DataX Interrupt (DATAXI)

The exception device endpoint interrupts are:

• The Underflow Interrupt (UNDERFI)