Motorola USB08 - Manual (Page 68)

Designer Reference Manual USB08 Evaluation Board
68 Universal Serial Bus (USB) Interface MOTOROLA
Universal Serial Bus (USB) Interface
At the end of the USB reset interrupt, the control endpoint 0 will be
enabled for receiving, thus the configuration instructions which follow
after the reset (device requests) are received by the USB receiver. This
option will be enabled by setting the RX0E bit in the USB control register
0 (UCR0).
The USB device is now in the DEFAULT state. That means the device is
attached to the bus and is supplied with current. In addition, it has
received a USB reset and reacts to instructions with the default address
zero. For further information, refer to Universal Serial Bus Specification
Revision 1.1, Chapter 9.1 — USB Device States.
After these fundamental initialization steps, further setup steps
summarized under the term of enumeration follow.
Bit 7 6 5 4 3 2 1 Bit 0
Read:
EOPIE SUSPND TXD2IE RXD2IE TXD1IE
0
TXD0IE RXD0IE
Write:
Reset: 0 0 0 0 0 0 0 0
= Unimplemented
Figure 4-3. USB Interrupt Register 0 (UIR0)
Bit 7 6 5 4 3 2 1 Bit 0
Read:
TOSEQ
0
TX0E RX0E TP0SIZ3 TP0SIZ2 TP0SIZ1 TP0SIZ0
Write:
Reset: 0 0 0 0 0 0 0 0
= Unimplemented
Figure 4-4. USB Control Register 0 (UCR0)