12-10
MCF5272 User’s Manual
Register Description and Programming Model
12.3.2.3 USB Real-Time Frame Monitor Register (RFMR)
The value in the RFMR can be used to determine approximately how much time has
elapsed since the USB host sent its last start-of-frame packet.
Because the hardware does not guarantee that any of the bit values are stable during the read
access:
•
only the higher-order bits should be used
•
the returned data should always be de-glitched by verifying that the same value is
seen on the higher-order bits for two consecutive read cycles.
Figure 12-5 shows the USB real-time frame monitor register.
Figure 12-5. USB Real-Time Frame Monitor Register (RFMR)
Table 12-5 lists field descriptions for the USB real-time frame monitor register.
12.3.2.4 USB Real-Time Frame Monitor Match Register (RFMMR)
To avoid intermediate false values in the real-time frame monitor match register
,
,
byte accesses are not supported and cause an access error.
Table 12-4. FNMR Field Descriptions
Bits
Name
Description
15–11
—
Reserved, should be cleared
10–0
FRM_MAT Frame number match value. Contains the USB frame number match value. When the FNR
value equals the value in the register, a FRM_MAT interrupt is generated.
15
14
13
0
Field
—
RTFM
Reset
0000_0000_0000_0000
R/W
Read
Addr
MBAR + 0x100A
Table 12-5. RFMR Field Descriptions
Bits
Name
Description
15–14
—
Reserved, should be cleared.
13–0
RTFM Real-time frame count. Contains the current USB frame counter value. The counter is
incremented one time for every USB bit time and is reset when a SOF packet from the
host is detected or an artificial start of frame (ASOF) interrupt is generated.
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 ...