Chapter 12. Universal Serial Bus (USB)
12-9
Register Description and Programming Model
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.
Figure 12-3. USB Frame Number Register (FNR)
Table 12-3 describes FNR fields.
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
byte accesses to this register are not supported and
cause an access error.
Figure 12-4. USB Frame Number Match Register (FNMR)
Table 12-4 describes FNMR fields.
15
11
10
0
Field
—
FRM
Reset
0000_0000_0000_0000
R/W
Read
Addr
MBAR + 0x1002
Table 12-3. FNR Field Descriptions
Bits
Name
Description
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.
15
11
10
0
Field
—
FRM_MAT
Reset
0000_0000_0000_0000
R/W
R/W
Addr
MBAR + 0x1006
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...