GD32F10x User Manual
331
Figure 15-37. Timing chart of down counting mode, change TIMERx_CAR ongoing
TIMER_CK
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)
Auto-reload register
120
99
change CAR Vaule
CNT_REG
5
4
3
2
1
0
99
1
0
120
Update event (UPE)
Update interrupt flag (UPIF)
Auto-reload register
120
99
change CAR Vaule
120
99
Auto-reload shadow register
...
Hardware set
Hardware set
Software clear
Hardware set
ARSE = 0
ARSE = 1
98
97
120
change CAR Vaule
119 118
120
Counter center-aligned counting
In this mode, the counter counts up from 0 to the counter-reload value and then counts down
to 0 alternatively. The Timer module generates an overflow event when the counter counts to
the counter-reload value subtract 1 in the up-counting mode and generates an underflow
event when the counter counts to 1 in the down-counting mode. The counting direction bit
DIR in the TIMERx_CTL0 register is read-only and indicates the counting direction when in
the center-aligned mode.
Setting the UPG bit in the TIMERx_SWEVG register will initialize the counter value to 0
irrespective of whether the counter is counting up or down in the center-align counting mode
and generates an update event.
The UPIF bit in the TIMERx_INTF register can be set to 1 either when an underflow event or
an overflow event occurs. While the CHxIF bit is associated with the value of CAM in
TIMERx_CTL0. The details refer to
Figure 15-38. Timing chart of center-aligned counting
If the UPDIS bit in the TIMERx_CTL0 register is set, the update event is disabled.
When an update event occurs, all the shadow registers (counter autoreload register, prescaler
register) are updated.
Summary of Contents for GD32F10 Series
Page 63: ...GD32F10x User Manual 63 programmed during the chip production ...
Page 117: ...GD32F10x User Manual 117 010 1 0 011 0 9 ...
Page 416: ...GD32F10x User Manual 416 shadow register updates every update event ...
Page 427: ...GD32F10x User Manual 427 value ...
Page 518: ...GD32F10x User Manual 518 These bits are not used in SPI mode ...