GD32F10x User Manual
274
Counter down counting
In this mode, the counter counts down continuously from the counter-reload value, which is
defined in the TIMERx_CAR register, to 0 in a count-down direction. Once the counter
reaches to 0, the counter the counter will start counting down from the counter-reload value
again and an underflow event will be generated. In addition, the update event will be
generated after (TIME1) times of underflow. The counting direction bit DIR in the
TIMERx_CTL0 register should be set to 1 for the down-counting mode.
When the update event is set by the UPG bit in the TIMERx_SWEVG register, the counter
value will be initialized to the counter-reload value 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 15-6. Timing chart of down counting mode, PSC=0/2
chart of down counting mode, change TIMERx_CAR ongoing
show some examples of
the counter behavior in different clock frequencies when TIMERx_CAR=0x99.
Figure 15-6. Timing chart of down counting mode, PSC=0/2
CEN
PSC_CLK
CNT_REG
5
4
3
2
1
0
99
98
97
96
95
94
93
92
Update event (UPE)
Update interrupt flag (UPIF)
CNT_REG
3
Update event (UPE)
Update interrupt flag (UPIF)
Hardware set
Software clear
Hardware set
PSC = 0
PSC = 2
TIMER_CK
91
PSC_CLK
2
1
0
99
98
Содержание GD32F10 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F10x Arm Cortex M3 32 bit MCU User Manual Revision 2 6 Jun 2022 ...
Страница 63: ...GD32F10x User Manual 63 programmed during the chip production ...
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Страница 416: ...GD32F10x User Manual 416 shadow register updates every update event ...
Страница 427: ...GD32F10x User Manual 427 value ...
Страница 518: ...GD32F10x User Manual 518 These bits are not used in SPI mode ...