AT89C5131A-L_06 Datasheet, PDF (120/185 Pages) ATMEL Corporation – 8-bit Flash Microcontroller with Full Speed USB Device

• Endpoint enable
Before using an endpoint, this one will be enabled by setting the EPEN bit in the
UEPCONX register.
An endpoint which is not enabled won’t answer to any USB request. The Default
Control Endpoint (Endpoint 0) will always be enabled in order to answer to USB
standard requests.
• Endpoint type configuration
All Standard Endpoints can be configured in Control, Bulk, Interrupt or Isochronous
mode. The Ping-pong Endpoints can be configured in Bulk, Interrupt or Isochronous
mode. The configuration of an endpoint is performed by setting the field EPTYPE
with the following values:
– Control:EPTYPE = 00b
– Isochronous:EPTYPE = 01b
– Bulk:EPTYPE = 10b
– Interrupt:EPTYPE = 11b
The Endpoint 0 is the Default Control Endpoint and will always be configured in
Control type.
• Endpoint direction configuration
For Bulk, Interrupt and Isochronous endpoints, the direction is defined with the
EPDIR bit of the UEPCONX register with the following values:
– IN:EPDIR = 1b
– OUT:EPDIR = 0b
For Control endpoints, the EPDIR bit has no effect.
• Summary of Endpoint Configuration:
Do not forget to select the correct endpoint number in the UEPNUM register before
accessing to endpoint specific registers.
Table 90. Summary of Endpoint Configuration
Endpoint Configuration
EPEN
EPDIR
Disabled
0b
Xb
Control
1b
Xb
Bulk-in
1b
1b
Bulk-out
1b
0b
Interrupt-In
1b
1b
Interrupt-Out
1b
0b
Isochronous-In
1b
1b
Isochronous-Out
1b
0b
EPTYPE
XXb
00b
10b
10b
11b
11b
01b
01b
UEPCONX
0XXX XXXb
80h
86h
82h
87h
83h
85h
81h
120 AT89C5131A-L
4338E–USB–06/06