
12-18
MCF5272 User’s Manual
MOTOROLA
Register Description and Programming Model
10
CFG_RAM_VAL
Enable USB conguration RAM. Noties the USB module that the user has loaded the
conguration RAM. Must be set in order for the USB module to process the USB
standard device requests that access the conguration RAM. These requests are
GET
_DESCRIPTOR, SET_CONFIGURATION, and SET_INTERFACE. When this bit is set,
accesses to the conguration RAM cause an access error.
0 Conguration RAM invalid
1 Conguration RAM valid
9
CMD_ERR
Command error for device request interface. Used to indicate to the endpoint controller
that an error has been encountered during class or vendor specic device request or
SYNCH_FRAME command processing. This command bit is write only and always
returns 0 when read.
Result of Request
CMD_OVER
CMD_ERR
Processed device request successfully
1
0
Error processing the request
1
Busy processing the request
0
X
Note: CMD_OVER and CMD_ERR have to be written simultaneously. The CMD_OVER
and CMD_ERR bits control the status stage response for vendor and class specic
requests.
8
CMD_OVER
Command over for device request interface. Used to indicate to the endpoint controller
that processing of a class or vendor specic device request or SYNCH_FRAME
command has been completed by the user. This command bit is write only and always
returns 0 when read.
Note: CMD_OVER and CMD_ERR have to be written simultaneously. The CMD_OVER
and CMD_ERR bits control the status stage response for vendor and class specic
requests.
7
CRC_ERR
CRC error generation enable. This bit enables CRC error generation for debug and test
purpose. In order to use this feature, the DEBUG bit must be set. Enabling this bit causes
a CRC error on the next data packet transmitted. The CRC_ERR bit must be set again in
order to generate another CRC error. This bit only applies to IN transfers. This command
bit is write-only and always returns 0 when read.
1 CRC error generation if DEBUG = 1
0 default value
6
—
Reserved, should be cleared.
5–4
OUT_LVL
Endpoint 0 OUT FIFO level for interrupt. This eld selects the FIFO level to generate an
OUT_LVL interrupt. The OUT_LVL interrupt is generated when the FIFO lls above the
selected level.
00 FIFO 25% Full
01 FIFO 50% Full
10 FIFO 75% Full
11 FIFO 100% Full
3–2
IN_LVL
Endpoint 0 IN FIFO level for interrupt. This eld selects the FIFO level to generate an
IN_LVL interrupt. The IN_LVL interrupt is generated when the FIFO falls below the
selected level.
00 FIFO 25% Empty
01 FIFO 50% Empty
10 FIFO 75% Empty
11 FIFO 100% Empty
Table 12-12. EP0CTL Field Descriptions (Continued)
Bits
Name
Description