How accuracy is internal HSI RC clock

[New.Fish]

Try to use STM32G0 LQFP32 MCU do accuracy frequency measurement, but there is no HSE crystal interface, so internal HSI RC will be for system clock, the accuracy of the system clock will affect the frequency, how accuracy is internal HSI RC clock

[S.Ma]

Electrical Characteristics chapter in the datasheet, oscillator parts.

Another way to measure is to use external precise 32.768k oscillator LSE typically used for RTC, and count pulses over a say precise 1 second to get Hertz value.

[New.Fish]

I find the internal HSI RC is 1% accuracy from the product overview in the website.

Thanks

[TDK · Accepted solution]

About ±0.5% at ambient, and then another ±2% at extreme temps, for about ±2.5% total, per the data sheet.