GD32W51x User Manual
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be changed on the go but is taken into account at the next update event.
Figure 17-3. Counter timing diagram with prescaler division change from 1 to 2
TIMER_CK
CEN
PSC_CLK
CNT_REG
Reload Pulse
Prescaler CNT
Prescaler BUF
F7
F8
F9
FA FB
FC
01
02
03
0
1
0
1
0
1
0
1
0
1
0
1
PSC value
0
04
UPG
0
Up counting mode
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 restarts from 0. If the repetition counter is set, the update
events will be generated after (TIME1) times of overflow. Otherwise the update
event is generated each time when overflows. 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 registers (repetition counter, auto reload register,
prescaler register) are updated.
Figure 17-4. Timing chart of up counting mode, PSC=0/1
of up counting mode, change TIMERx_CAR ongoing
show some examples of the counter
behavior for different clock prescaler factor when TIMERx_CAR=0x63.