Rainbow Electronics AT91CAP9S250A - Manual (Page 860)

860
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
Figure 44-9. 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 44-10. 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 pre-
caution 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 IN ACK Data OUT Token OUT ACK Data 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