AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 99

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

Configuration
General Configuration
Endpoint Configuration
4202D–SCR–06/05
Endpoint 0
Endpoint 6
UEPSTA0
UEPSTA6
•
Before any USB transaction, the 48 MHz required by the USB controller must be cor-
rectly generated (Section "Clock Controller", page 41).
The USB controller should be then enabled by setting the USBE bit in the USBCON
register.
•
After a Reset or a USB reset, the software has to set the FEN (Function Enable) bit in
the USBADDR register. This action will allow the USB controller to answer to the
requests sent at the address 0.
When a SET_ADDRESS request has been received, the USB controller must only
answer to the address defined by the request. The new address should be stored in the
USBADDR register. The FEN bit and the FADDEN bit in the USBCON register should
be set to allow the USB controller to answer only to requests sent at the new address.
•
The CONFG bit in the USBCON register should be set after a SET_CONFIGURATION
request with a non-zero value. Otherwise, this bit should be cleared.
•
The endpoint register access is performed using the UEPNUM register. The following
registers
correspond to the endpoint whose number is stored in the UEPNUM register. To select
an Endpoint, the firmware has to write the endpoint number in the UEPNUM register.
Figure 53. Endpoint Selection
USB controller enable
Set address
Set configuration
Selection of an Endpoint
–
–
–
–
UEPSTAX,
UEPCONX,
UEPDATX,
UBYCTX,
UEPCON0
UEPCON6
UBYCT6
UBYCT0
UEPDAT0
UEPDAT6
UEPNUM
0
1
2
3
4
5
6
X
UEPSTAX
SFR Registers
UEPCONX
UBYCTX
UEPDATX
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