Universal Serial Bus (USB)
MCF5272 ColdFire Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
12-15
12.3.2.10 USB Endpoint 0 IN Configuration Register (IEP0CFG)
Figure 12-13 shows the USB Endpoint 0 IN configuration (IEP0CFG) register.
Table 12-11 lists field descriptions for the IEP0CFG register. Only longword writes are allowed. The
maximum packet size for endpoint 0 is eight bytes. Writing to the register resets the FIFO. Any data in the
FIFO are discarded, and the associated EPnDP register is also reset.
2
HALT_ST
Current endpoint 0 halt status. Indicates whether endpoint 0 is currently halted or active. Endpoint
0 is halted if there is an error processing a request. A halt is cleared automatically by a SETUP
packet.
1 Endpoint 0 halted
0 Endpoint 0 active
1
DIR
Current endpoint 0 direction. Indicates whether endpoint 0 is currently accessed as an IN or OUT
endpoint.
1 The endpoint is configured as an IN endpoint
0 The endpoint is configured as an OUT endpoint
0
—
Reserved, should be cleared.
31
22
21
20
16
Field
MAX_PACKET
—
FIFO_SIZE
Reset
0000_0000_0000_0000
R/W
15
11
10
9
0
Field
FIFO_SIZE
—
FIFO_ADDR
Reset
0000_0000_0000_0000
R/W
Addr
MBAR + 0x1028
Figure 12-13. USB Endpoint 0 IN Configuration Register (IEP0CFG)
Table 12-11. IEP0CFG Field Descriptions
Bits
Name
Descriptions
31–22
MAX_PACKET
Maximum packet size. Must be written with the maximum packet size defined in the device
descriptor for endpoint 0 or the endpoint descriptors for other endpoints.
21
—
Reserved, should be cleared.
20–11
FIFO_SIZE
Size of the FIFO. Sets the depth of the FIFO buffer for the endpoint. The FIFO size must be a power
of 2. For non-isochronous endpoints, the FIFO size must be at least two times the maximum packet
size.
10
—
Reserved, should be cleared.
9–0
FIFO_ADDR
Starting address in the FIFO buffer memory for the endpoint’s FIFO. Reading this field returns the
current write pointer for IN endpoints or the read pointer for OUT endpoints for the FIFO.
Table 12-10. EP0SR Field Descriptions
Bits
Name
Descriptions