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17.3
Operation of the USB Function
This section describes the flow of data transfer, CPU access operation, and DMA
operation by the USB function.
■ Operation of the USB Function
This section explains the following items of operation:
•
Flow of data transfer
•
Setup stage of control transfer (most standard commands)
•
Setup stage of control transfer (class and vendor commands and some standard
commands [Get_Descriptor, Set_Descriptor, and Synch_Frame])
•
Status stage of control transfer (most standard commands)
•
Status stage of control transfer (class and vendor commands and some standard
commands [Get_Descriptor, Set_Descriptor, and Synch_Frame])
•
Control transfer (data stage) or BULK OUT transfer
•
Control transfer (data stage), bulk transfer, or INTERRUPT IN transfer
•
CPU access operation
•
CPU IN transfer
•
CPU OUT transfer
•
DMA operation
•
DMA IN transfer
•
DMA OUT transfer
•
Read and write timing diagrams for DMA single transfer
•
Read and write timing diagrams for DMA block transfer
•
Interrupt sources
•
Setting of end point buffer
•
Examples of software control
•
Setup
•
Reception at CPU access
•
Transmission at CPU access
•
DMA reception
•
DMA transmission
CHAPTER 17 USB FUNCTION
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