Overview Of The Usb Function - Fujitsu MB91319 Series Hardware Manual

CHAPTER 17 USB FUNCTION
17.1

Overview of the USB Function

The USB function consists of a protocol engine, physical end points (FIFO buffers)
required for data transfer, CPU DMA interface, and other components. The USB function
carries out the protocol processing to be done by a USB function device.
■ Overview of the USB Function
The USB function consists of the following blocks:
❍ USB protocol engine
The USB protocol engine handles the basic USB communication protocol to reduce the load on
application programs.
Note:
The following processing must be handled by application programs:
• Processing of class and vendor requests
• Set_Descriptor, Get_Descriptor, and Synch_Frame processing for standard requests
❍ FIFO buffers for end points
For control:
IN: 8 bytes
OUT: 8 bytes
For bulk transfer:
IN: 64 bytes × 2 (double buffer)
OUT: 64 bytes × 2 (double buffer)
For interrupt transfer:
IN: 8 bytes
❍ Interface (internal bus interface circuit) between end point and protocol engine
❍ Registers
❍ CPU DMA interface circuit
CPU interface: 16 bits (CS2X)
DMA interface: 16 bits (DREQ0, DREQ1)
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