GD32F20x User Manual
458
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 to count once again from 0. 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.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to 0 and generates an update event.
If the UPDIS bit in TIMERx_CTL0 register is set, the update event is disabled.
When an update event occurs, all the registers (repetition counter, auto reload register,
prescaler register) are updated.
The following figures show some examples of the counter behavior for different clock
prescaler factor when TIMERx_CAR=0x63.
Figure 18-69. Up-counter timechart, PSC=0/1
CEN
CNT_CLK(PSC_CLK)
CNT_REG
5E
5F
60
61
62
63
00
01
02
03
04
05
06
07
Update event (UPE)
Update interrupt flag (UPIF)
CNT_REG
5F
60
Update event (UPE)
Update interrupt flag (UPIF)
Hardware set
Software clear
Hardware set
TIMERx_PSC PSC == 0
TIMERx_PSC PSC == 1
TIMER_CK
08
63
62
61
00
01
02
03
CNT_CLK(PSC_CLK)
Содержание GD32F20 Series
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Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
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Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...