Rainbow Electronics AT89C5122 - Manual (Page 100)

100
AT8xC5122/23
4202E–SCR–06/06
• Endpoint enable
Before using an endpoint, this one should 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) should 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 should always be configured in Con-
trol 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:
Make sure to select the correct endpoint number in the UEPNUM register before
accessing to endpoint specific registers.
Table 62. Summary of Endpoint Configuration
Endpoint configuration EPEN EPDIR EPTYPE UEPCONX
Disabled 0b Xb XXb 0XXX XXXb
Control 1b Xb 00b 80h
Bulk-In 1b 1b 10b 86h
Bulk-Out 1b 0b 10b 82h
Interrupt-In 1b 1b 11b 87h
Interrupt-Out 1b 0b 11b 83h
Isochronous-In 1b 1b 01b 85h
Isochronous-Out 1b 0b 01b 81h