Datasheet

SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
840
Figure 37-10. Data IN Followed By Status OUT Transfer at the End of a Control Transfer
Note: A NAK handshake is always generated at the first status stage token.
Figure 37-11. Data OUT Followed by Status IN Transfer
Note: Before proceeding to the status stage, the software should determine that there is no risk of extra data from
the host (data stage). If not certain (non-predictable data stage length), then the software should wait for a
NAK-IN interrupt before proceeding to the status stage. This precaution should be taken to avoid collision
in the FIFO.
Token OUT
Data IN
Token IN
ACK
ACK
Data OUT (ZLP)
RX_BK_RDY
(UDPHS_EPTSTAx)
TX_COMPLT
(UDPHS_EPTSTAx)
Set by Hardware
Set by Hardware
USB Bus
Packets
Cleared by Firmware
Cleared by Firmware
Device Sends a
Status OUT to Host
Device Sends the Last
Data Payload to Host
Interrupt
Pending
Token OUT
ACK
Data OUT (ZLP)
Token INACKData OUTToken OUT ACKData IN
USB Bus
Packets
RX_BK_RDY
(UDPHS_EPTSTAx)
Cleared by Firmware
Set by Hardware
Clear by Hardware
TX_PK_RDY
(UDPHS_EPTSTAx)
Set by Firmware
Host Sends the Last
Data Payload to the Device
Device Sends a Status IN
to the Host
Interrupt Pending