AT32F425
Series Reference Manual
2022.03.30
Page 352
Ver 2.01
shows the HFIR behavior when the HFIRRLDCTRL is set to 0x0 in the OTGFS_HFIR
register.
Figure 20-5 HFIR behavior when HFIRRLDCTRL=0x0
(4)HFIR Counter
restarts
SOF
HFIR DN
Counter
Application Load
Of HFIR
HFIR
1
0 400 399
450
1
0 400
********************
********************
1
*************
450
0
******************** 1
450
0
499
(1)Old HFIR Value
(2)HFIR Reloaded
(3)SOF Lost
Synchronization Due
to HFIR Reload
(5)New HFIR Value
(6)SOF back in
Synchronization
400
450
The sequence of operation is as follows:
1.
After power-on reset, the current HFIR value set by the application is shown
2.
The application loads a new value into the HFIR register
3.
The HFIR downcounter is reloaded, so it will immediately restart counting to cause SOF
synchronization loss
4. Restart HFIR counter
5. The HFIR register receives a new programmed value
6. Obtain SOF synchronization again after the first SOF is generated using the HFIR new feature
shows the HFIR behavior when HFIRRLDCTRL=0x1 in the OTGFS_HFIR register.