Atmel SAM9X25, Manual

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• ERR_FLUSH: At least one packet has been sent inside the microframe, but the number of
token IN received is lesser than the number of transactions actually validated (TX_BK_RDY)
and likewise with the NB_TRANS programmed.
• ERR_TRANS: At least one packet has been sent inside the microframe, but the number of
token IN received is lesser than the number of programmed NB_TRANS transactions and the
packets not requested were not validated.
• ERR_ ERR_FLUSH: At least one packet has been sent inside the microframe, but
the data has not been validated in time to answer one of the following token IN.
• ERR_ ERR_TRANS: At least one packet has been sent inside the microframe, but
the data has not been validated in time to answer one of the following token IN and the data
can be discarded at the microframe end.
• ERR ERR_TRANS: The first token IN has been answered and it was the only one
received, a second bank has been validated but not the third, whereas NB_TRANS was
waiting for three transactions.
• ERR_ ERR ERR_TRANS: The first token IN has been treated, the data
for the second Token IN was not available in time, but the second bank has been validated
before the end of the microframe. The third bank has not been validated, but three
transactions have been set in NB_TRANS.
33.6.9.9 Data OUT
33.6.9.10 Bulk OUT or Interrupt OUT
Like data IN, data OUT packets are sent by the host during the data or the status stage of con-
trol transfer or during an interrupt/bulk/isochronous OUT transfer. Data buffers are sent packet
by packet under the control of the application or under the control of the DMA channel.
33.6.9.11 Bulk OUT or Interrupt OUT: Receiving a Packet Under Application Control (Host to Device)
Algorithm Description for Each Packet:
• The application enables an interrupt on RX_BK_RDY.
• When an interrupt on RX_BK_RDY is received, the application knows that UDPHS_EPTSTAx
register BYTE_COUNT bytes have been received.
• The application reads the BYTE_COUNT bytes from the endpoint.
• The application clears RX_BK_RDY.
Note: If the application does not know the size of the transfer, it may not be a good option to use
AUTO_VALID. Because if a zero-length-packet is received, the RX_BK_RDY is automatically
cleared by the AUTO_VALID hardware and if the endpoint interrupt is triggered, the software will
not find its originating flag when reading the UDPHS_EPTSTAx register.
Algorithm to Fill Several Packets:
• The application enables the interrupts of BUSY_BANK and AUTO_VALID.
• When a BUSY_BANK interrupt is received, the application knows that all banks available for
the endpoint have been filled. Thus, the application can read all banks available.
If the application doesn’t know the size of the receive buffer, instead of using the BUSY_BANK
interrupt, the application must use RX_BK_RDY.