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GD32F403xx User Manual
257
times of overflow events. The counting direction bit DIR in the TIMERx_CTL0 register should
be set to 0 for the up counting mode.
Whenever, if the update event software trigger is enabled by setting the UPG bit in the
TIMERx_SWEVG register, the counter value will be initialized to 0 and generates an update
event.
If set the UPDIS bit in TIMERx_CTL0 register, the update event is disabled.
When an update event occurs, all the shadow registers (repetition counter, counter auto
reload register, prescaler register) are updated.
Figure 16-4. Timing chart of up counting mode, PSC=0/2
show some examples of the
counter behavior for different clock prescaler f actor when TIMERx_CAR=0x99.
Figure 16-4. Timing chart of up counting mode, PSC=0/2
CEN
PSC_CLK
CNT_REG
94
95
96
97
98
99
0
1
2
3
4
5
6
7
Update event (UPE)
Update interrupt flag (UPIF)
CNT_REG
96
Update event (UPE)
Update interrupt flag (UPIF)
Hardware set
Software clear
Hardware set
PSC = 0
PSC = 2
TIMER_CK
8
PSC_CLK
97
98
99
0
1