Digi NS9750 User Manual
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U S B D e v i c e E n d p o i n t F I F O C o n t r o l a n d D a t a r e g i s t e r s
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N S 9 7 5 0 H a r d w a r e R e f e r e n c e
Device endpoint status
Table 449 defines the device endpoint status provided for each endpoint FIFO.
Firmware uses this information to know which endpoints are active and whether
there were any transmission errors.
Status
Direction
Description
ACK
In
Set when an ACK packet is received from the host in response to the
previous data packet. For isochronous pipes, the ACK field is asserted
automatically for each packet sent to the host.
NACK
In
Set when a NACK packet is sent to the host in response to the
previous setup packet received from the host.
ERROR
In
Set when an ACK packet is not received from the host in response to
the previous data packet sent to the host.
ACK
Out
Set when an ACK packet is sent to the host in response to the previous
error-free packet received from the host. For isochronous pipes, this
field is asserted automatically for each packet received from the host
if the data is error-free.
NACK
Out
Set when a NACK packet is sent to the host in response to the
previous setup packet received from the host.
ERROR
Out
Set when a packet is received from the host and a transmission error
was found.
Table 449: USB device endpoint status