Cypress EX-USB FX3 Programmer's Manual page 70

FX3 Firmware
Figure 5-7. Manual In Channel
Buffer low threshold
interrupt (optional)
Manual Out Channel
The DMA_TYPE_MANUAL_OUT channel is a special channel where the CPU (FX3 firmware) is the
producer of data. The user application needs to get the active data buffer, populate the buffer, and
then commit it.
Figure 5-8. Manual Out Channel
CPU
Descriptor list
D0
Many-to-One Manual Channel
This channel is defined as DMA_TYPE_MANUAL_MANY_TO_ONE is a variation of the manual
channel. It is defined by more than one valid producer socket, a valid consumer socket, and a
predetermined amount of buffering; each of these is a user programmable parameter.
This type of channel is used when the data flow from many producers (at least 2 producers) has to
70
Producer
Incoming data
(Ingress)
Socket
Consume
event signaling
CPU interrupt on every N
Ingress buffers
Use buffer
Buffer ready?
Yes
Produce Event Signaling
Data
Buffer
D1 D2
Buffer
D0 D1
Descriptor chain
Outgoing data
Consumer
(Egress)
Socket
CPU interrupt after
every N buffers
Dn
FX3 Programmers Manual, Doc. # 001-64707 Rev. *C
D2 Dn
Buffer low threshold
interrupt (optional)