AT91RM3400-AI-001 ATMEL [ATMEL Corporation], AT91RM3400-AI-001 Datasheet - Page 410

• Manufacturer Part Number: AT91RM3400-AI-001
• Manufacturer: ATMEL [ATMEL Corporation]

Status OUT Transfer
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AT91RM3400
Once a control request has been processed and the requested data returned, the host
acknowledges by sending a zero length packet. This is a zero length Data OUT transaction.
1. The USB device receives a zero length packet. It sets RX_DATA_BK0 flag in the
2. The microcontroller is notified that the USB device has received a zero length packet
3. The microcontroller must clear RX_DATA_BK0.
Figure 173. Data IN Followed by Status OUT Transfer
USB_CSRx register and acknowledges the zero length packet.
sent by the host polling RX_DATA_BK0 in the USB_CSRx register. An interrupt is
pending while RX_DATA_BK0 is set. The number of bytes received in the endpoint’s
USB_BCR register is equal to zero.
USB Bus
Packets
RX_DATA_BKO
(USB_CSRx)
TXCOMP
(USB_CSRx)
PID
Data IN
Device Sends the Last
Data Payload to Host
Set by USB Device
Data IN
Set by USB Device
ACK
PID
Cleared by Firmware
Device Sends a
Status OUT to Host
Data OUT
PID
ACK
PID
Interrupt Pending
Cleared by Firmware
1790A–ATARM–11/03