ATXMEGA128A4U-AU Datasheet, PDF (38/121 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA A4U Microcontroller

XMEGA A4U
DMA Controller can then read/write one data buffer while the USB module writes/reads the
other, and vice versa. This gives double buffered communication.
Multi-packet transfer enables a data payload exceeding the maximum packet size of an end-
pointto be transferred as multiple packets without software intervention. This reduce the CPU
intervention and the interrupts needed for USB transfers.
For low power operation, the USB module can put the microcontroller in any sleep mode when
the USB bus is idle and a suspend condition is given. Upon bus resume, the USB module can
wake the microcontroller from any sleep mode.
PORTD has one USB. Notation of this is USB.
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8387A–AVR–07/11