Motorola USB08 - page 68

Designer Reference Manual USB08 Evaluation Board
68 Universal Serial Bus (USB) Interface MOTOROLA
Universal Serial Bu s (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 t he US B recei ve r. T his
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 7654321Bit 0
Read:
EOPIE SUSPND TXD2IE RXD2IE TXD1IE
0
TXD0IE RXD0IE
Write:
Reset:00000000
= Unimplemented
Figure 4-3. USB Interrupt Register 0 (UIR0)
Bit 7654321Bit 0
Read:
TOSEQ
0
TX0E RX0E TP0SIZ3 TP0SIZ2 TP0SIZ1 TP0SIZ0
Write:
Reset:00000000
= Unimplemented
Figure 4-4. USB Control Register 0 (UCR0)