Register Descriptions - Motorola DigitalDNA ColdFire MCF5272 User Manual

12.3.2 Register Descriptions

The following are detailed register diagrams and field descriptions.
12.3.2.1 USB Frame Number Register (FNR)
Once every 1 ms, the USB host issues a start-of-frame packet containing a frame number. The FNR
register captures this frame number. Figure 12-3 shows the FNR.
15
Field
Reset
R/W
Addr
Figure 12-3. USB Frame Number Register (FNR)
Table 12-3 describes FNR fields.
Bits Name
15–11 — Reserved, should be cleared.
10–0 FRM USB frame number. Contains the current USB frame number. FRM is updated with the new frame
number each time the device successfully receives a start-of-frame (SOF) packet from the USB
host. The new frame number is contained in the SOF packet.
12.3.2.2 USB Frame Number Match Register (FNMR)
FNMR is used to signal, via the FRM_MAT interrupt, when a particular frame number is
issued by the USB host. To avoid a false match during intermediate states of a byte write
operation to the FNMR
cause an access error.
15
Field
Reset
R/W
Addr
Figure 12-4. USB Frame Number Match Register (FNMR)
Table 12-4 describes FNMR fields.
11 10
—
0000_0000_0000_0000
MBAR + 0x1002
Table 12-3. FNR Field Descriptions
byte accesses to this register are not supported and
, Figure 12-4,
11 10
—
0000_0000_0000_0000
MBAR + 0x1006
Chapter 12. Universal Serial Bus (USB)
Register Description and Programming Model
FRM
Read
Description
FRM_MAT
R/W
0
0
12-9