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GD32A50x User Manual
423
Figure 18-44. Timing chart of PSC value change from 0 to 2
TIMER_CK
CEN
PSC_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler
shadow
94
95
96
97
98
99
0
2
0
2
0
1
2
0
1
2
0
1
PSC value
UPG
0
2
0
1
2
Counter up counting
In this mode, the counter counts up continuously from 0 to the counter-reload value, which is
defined in the TIMERx_CAR register, in a count-up direction. Once the counter reaches the
counter reload value, the counter will start counting up from 0 again. The update event is
generated at each counter overflow. The counting direction bit DIR in the TIMERx_CTL1
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 an update event will
be generated.
If the UPDIS bit in TIMERx_CTL0 register is set, the update event is disabled.
When an update event occurs, all the shadow registers (counter auto reload register,
prescaler register) are updated.
Figure 18-45. Timing chart of up counting mode, PSC=0/2
chart of up counting, change TIMERx_CAR on the go
show some examples of the counter
behavior for different clock prescaler factor when TIMERx_CAR=0x99.