at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 409

• Manufacturer Part Number: at91rm3400
• Description: Atmel Advanced At91 Arm Microcontroller
• Manufacturer: ATMEL Corporation

Status IN Transfer
1790A–ATARM–11/03
Once a control request has been processed, the device returns a status to the host. This is a
zero length Data IN transaction.
1. The microcontroller waits for TXPKTRDY in the USB_CSRx endpoint’s register to be
2. Without writing anything to the USB_FDRx endpoint’s register, the microcontroller sets
3. This packet is acknowledged by the host and TXPKTRDY is set in the USB_CSRx end-
Figure 172. Data Out Followed by Status IN Transfer.
USB Bus
Packets
RX_DATA_BKO
(USB_CSRx)
TXPKTRDY
(USB_CSRx)
cleared. (At this step, TXPKTRDY must be cleared because the previous transaction
was a setup transaction or a Data OUT transaction.)
TXPKTRDY. The USB device generates a Data IN packet using DATA1 PID.
point’s register.
Host Sends the Last
Data Payload to the Device
PID
Data OUT
Set by USB Device
Set by Firmware
Data OUT
NAK
PID
Device Sends a Status IN
to the Host
Interrupt Pending
Data IN
PID
Cleared by Firmware
PID
ACK
AT91RM3400
Cleared by USB Device
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