topic Re: KW45 Slow IRC Control Status Register (SIRCCSR) Missing Enable Function in Wireless MCU

KW45 Slow IRC Control Status Register (SIRCCSR) Missing Enable Function

YohanH — Thu, 02 Oct 2025 08:41:06 GMT

Good Morning,

With KW45B41Z83.

I am currently configuring the KW45 in the Slow IRC section and am surprised to find that the enable function is not prensent in regsiter diagram and field in the KW45 Reference Manual, Rev. 8, June 2024. I would expect to see a SIRCENregistry available like FIRCEN for fast IRC.

In the list of functions available in the registry, it appears to be present.

In the reference Manual:
Function
Contains Slow IRC Selected, Slow IRC Valid, Lock Register , Slow IRC Stop Enable , Slow IRC Enable.

See attachement for more detail.

Yohan,
Best Regards

Re: KW45 Slow IRC Control Status Register (SIRCCSR) Missing Enable Function

luis_maravilla — Thu, 02 Oct 2025 18:17:19 GMT

Hello Yohan,

There isn't a register for Slow IRC Enable such as the Fast IRC Enable (FIRCEN); The registers available for initialize the SIRC are the registers from the Reference Manual Chapter 26.4.1.8.

In Reference Manual Chapter 26.3 Table 197 is the description for entering SIRC mode operation.

Also, I would add the CLOCK_InitSirc information that Initializes the SCG slow IRC clock, for more information please refer to MCUXpresso SDK Documentation-Init SIRC

Best Regards

Luis