Rainbow Electronics AT91CAP9S250A - Manual (Page 843)

843
6264A–CAP–21-May-07
AT91CAP9S500A/AT91CAP9S250A
Figure 43-2. USB Host Communication Channels
43.4.2 Host Controller Driver
Figure 43-3. USB Host Drivers
USB Handling is done through several layers as follows:
• Host controller hardware and serial engine: Transmits and receives USB data on the bus.
• Host controller driver: Drives the Host controller hardware and handles the USB protocol.
Operational
Registers
Mode
HCCA
Status
Event
Frame Int
Ratio
Control
Bulk
Host Controller
Communications Area
Interrupt 0
Interrupt 1
Interrupt 2
Interrupt 31
Done
. . .
. . .
Open HCI
Shared RAM
Device Register
in Memory Space
Device Enumeration
= Transfer Descriptor = Endpoint Descriptor
. . .
Host Controller Hardware
HUB Driver
Host Controller Driver
USB Driver
Mini Driver Class Driver Class Driver
User Application
Kernel Drivers
User Space
Hardware