ST STM32F31xx User Manual page 532

General-purpose timers (TIM)
TIM_Update_Source

#define: TIM_UpdateSource_Global ((uint16_t)0x0000)
Source of update is the counter overflow/underflow or the setting of UG bit, or an update
generation through the slave mode controller.

#define: TIM_UpdateSource_Regular ((uint16_t)0x0001)
Source of update is counter overflow/underflow.
532/584 DocID023800 Rev 1
UM1581