Rainbow Electronics AT89C51SND1C - Manual (Page 85)

85
AT8xC51SND1C
4109E–8051–06/03
• Endpoint enable
Before using an endpoint, this must be enabled by setting the EPEN bit in the UEP-
CONX 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
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 endpoint specific registers.
Table 89. 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