Cypress EX-USB FX3 - Page 69

FX3 Programmers Manual, Doc. # 001-64707 Rev. *C 69
FX3 Firmware
Figure 5-6. Manual Channel
Manual In Channel
The DMA_TYPE_MANUAL_IN channel is a special channel where the CPU (FX3 firmware) is the
consumer of the data. A callback must be registered at channel creation time and this is invoked to
the user application when a specified (default is one) number of buffers are transferred.
Callback function invoked at
end of transaction
Producer
(Ingress)
Socket
Consumer
(Egress)
Socket
D0_P D1_P D2_P Dn_P
Incoming data
Outgoing data
CPU interrupt on every
Ingress buffer
Buffer inspection/modification
Consume
event signaling
Discard buffer?
NO
YES
Modified data
D0_C D1_C D2_C D3_C
Consume descriptor update
Buffer
Producer descriptor list Consumer descriptor list
Consume
event signaling
Produce event
signaling