at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 427

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

AT91RM3400
1 = No effect.
This flag is used to notify the USB device firmware that a valid Setup data packet has been sent by the host and success-
fully received by the USB device. The USB device firmware may transfer Setup data from the FIFO by reading the
USB_FDRx register to the microcontroller memory. Once a transfer has been done, RXSETUP must be cleared by the
device firmware.
Ensuing Data OUT transactions is not accepted while RXSETUP is set.
• STALLSENT: Stall sent (Control, Bulk Interrupt endpoints)/ ISOERROR (Isochronous endpoints)
This flag generates an interrupt while it is set to one.
STALLSENT: this ends a STALL handshake
Read
0 = the host has not acknowledged a STALL.
1 = host has acknowledge the stall.
Write
0 = reset the STALLSENT flag, clear the interrupt.
1 = No effect.
This is mandatory for the device firmware to clear this flag. Otherwise the interrupt remains.
Please refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 to get more information on the
STALL handshake.
ISOERROR: a CRC error has been detected in an isochronous transfer
Read
0 = No error in the previous isochronous transfer.
1 = CRC error has been detected, data available in the FIFO are corrupted.
Write
0 = reset the ISOERROR flag, clear the interrupt.
1 = No effect.
• TXPKTRDY: Transmit Packet Ready
This flag is cleared by the USB device.
This flag is set by the USB device firmware.
Read
0 = Data values can be written in the FIFO.
1 = Data values can not be written in the FIFO.
Write
0 = No effect.
1 = A new data payload is has been written in the FIFO by the firmware and is ready to be sent.
This flag is used to generate a Data IN transaction (device to host). Device firmware checks that it can write a data payload
in the FIFO, checking that TXPKTRDY is cleared. Transfer to the FIFO is done by writing in the USB_FDRx register. Once
the data payload has been transferred to the FIFO, the firmware notifies the USB device setting TXPKTRDY to one. USB
bus transactions can start. TXCOMP is set once the data payload has been received by the host.
• FORCESTALL: Force Stall (used by Control, Bulk and Isochronous endpoints)
Write-only
0 = No effect.
1 = Send STALL to the host.
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