Cypress EX-USB FX3, Руководство программиста

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FX3 Programmers Manual, Doc. # 001-64707 Rev. *C 67
FX3 Firmware
Figure 5-4. Auto Channel
Auto Channel with Signaling
This channel is a minor variant of the DMA_TYPE_AUTO channel. The channel set up and data flow
remains the same. The only change is that an event is raised to the user application every time a
buffer is committed by the DMA. The buffer pointer and the data size are communicated to the
application. This is useful for data channels where the data needs to be inspected for activities such
as collection of statistics.
■
The actual data flow is not impeded by this inspection; the DMA continues uninterrupted.
■
The notification cannot be used to modify the contents of the DMA buffer.
Figure 5-5. Auto Channel with Signaling
Many-to-One Auto Channel
This channel is defined as DMA_TYPE_AUTO_MANY_TO_ONE is a variation of the auto channel. It
is defined by more than one valid producer sockets, a valid consumer socket, and a predetermined
amount of buffering; each of these is a user programmable parameter.
Callback function invoked at
the end of transfer
Producer
(Ingress)
Socket
Consumer
(Egress)
Socket
D0 D1 D2 Dn
Incoming data Outgoing data
Produce and consume
event signaling
Buffer
Descriptor chain
Callback function invoked at
the end of transfer
Producer
(Ingress)
Socket
Consumer
(Egress)
Socket
D0 D1 D2 Dn
Incoming data Outgoing data
Produce and Consume
event signaling
Buffer
Descriptor chain
Event generated when each
packet is forwarded