Use the SysTick Calibration Value Register to enable software to scale to any required speed using divide and multiply.
| TENMS | An optional Reload value to be used for 10ms (100Hz) timing, subject to system clock skew errors. If the value reads as 0, the calibration value is not known. |
| SKEW | If reads as 1, the calibration value for 10ms is inexact (due to clock frequency). |
| NOREF | If reads as 1, the Reference clock is not provided - the CLKSOURCE bit of the SysTick Control and Status register will be forced to 1 and cannot be cleared to 0. |