RCC internal clock sources calibration register 3
| HSICAL | HSI16 clock calibration These bits are initialized at startup with the factory-programmed HSI16 calibration value. When HSITRIM[4:0] is written, HSICAL[11:0] is updated with the sum of HSITRIM[4:0] and the initial factory trim value. |
| HSITRIM | HSI16 clock trimming These bits provide an additional user-programmable trimming value that is added to the HSICAL[11:0] bits. It can be programmed to adjust to voltage and temperature variations that influence the frequency of the HSI16. |