Cypress FM4 Series - High-Speed CR Trimming Function Setup Procedure Example

CHAPTER 2-3: High-Speed CR Trimming
FM4 Peripheral Manual, Doc. No. 002-04856 Rev. *E 117
4. High-Speed CR Trimming Function Setup Procedure Example
This section provides an example of setting up frequency trimming function of the high-speed CR
oscillator.
Frequency Trimming Setup
Ta ke the steps shown in Figure 4-1 to set up frequency trimming.
1. Write 0x1ACCE554 to TRMLCK[31:0] bits of High-speed CR frequency Register Write Protection
register (MCR_RLR) to release the lock of Frequency Trimming Setup Register (MCR_FTRM)/
Temperature Trimming Setup Register (MCR_TTRM).
2. Set the trimming data to TRT bit of Temperature Trimming Setup Register (MCR_TTRM).
3. Set TRD bit of Frequency Trimming Setup Register (MCR_FTRM).
4. Write a value other than 0x1ACCE554 to TRMCLK[31:0] bits of High-speed CR Oscillation Register
Write Protection Register (MCR_RLR) to lock the Frequency Trimming Setup Register (MCR_FTRM)/
Temperature Trimming Setup Register (MCR_TTRM).
Figure 4-1 Frequency/Temperature Trimming Setup
Start
Unlock the register
MCR_RLR:TRMLCK[31:0] = 0x1ACC_E554
Frequency Trimming Register settings
MCR_FTRM:TRD
Lock the register
MCR_RLR:TRMLCK[31:0] = 0x000_0000
End
* Write a value other than 0x1ACC_E554
Temperature Trimming Register settings
MCR_TTRM:TRT