pub type TickintW<'a, REG> = BitWriter<'a, REG, Tickint>;
Field TICKINT writer - Enables SysTick exception request
TICKINT
pub struct TickintW<'a, REG> { /* private fields */ }
counting down to 0 does not assert the SysTick exception request
counting down to 0 asserts the SysTick exception request