Cypress FM4 Series - Page 121

CHAPTER 2-3: High-Speed CR Trimming
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 121
Frequency Trimming Procedure Example
Figure 4-4 shows a trimming procedure example of high-speed CR oscillation.
Figure 4-4 Trimming Procedure Example of High-speed CR Oscillation
Set the input into base timer as CR
division clock by the Extended Function
Pin Setup Register(EPFR04).
Start
Set the master clock as the main oscillation
clock by the SCM_CTL register
(RCS[2:0]:SCM_CTL = 001)
Unlock the MCR_FTRM register
Write 0x1ACC_E554 to the MCR_RLR register
Set the division ratio of high-speed CR
oscillation to be input into input capture/
base timer by the MCR_PSR register
Calculate Xtrm
(See an Xtrm calculation procedure example)
Set the calculated Xtrm
as the MCR_FTRM register
Lock the MCR_FTRM register
Write 0x0000_0000 to the MCR_RLR register
(Note: Write a value other than 0x1ACC_E554)
E
Set the Temperature Setup register
End