SKEW=value1, NOREF=value1
SysTick Calibration Value Register r
| TENMS | Ten Milliseconds Reload Value |
| SKEW | Ten Milliseconds Skewed 0 (value1): TENMS value is exact 1 (value2): TENMS value is inexact, or not given. |
| NOREF | No Reference Clock 0 (value1): reference clock provided 1 (value2): no reference clock provided. |