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Nations Technologies Inc.
Tel
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+86-755-86309900
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Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
• The prescaler shadow register is reloaded with the preload value(TIMx_PSC).
To avoid updating the shadow registers when new values are written to the preload registers, you can disable the
update by setting TIMx_CTRL1.UPDIS=1.
When an update event occurs, the counter will still be cleared and the prescaler counter will also be set to 0 (but the
prescaler value will remain unchanged).
The figure below shows some examples of the counter behavior and the update flags for different division factors in
the up-counting mode.
Figure 11-3 Timing diagram of up-counting. The internal clock divider factor = 2/N
CK_PSC
CNTEN
Timer clock = CK_CNT
Counter register
Counter overflow
Update interrupt flag(UDITF)
0034
0035
Update event(UEV)
0036
0000
0001
0002
0003
CK_PSC
Timer clock = CK_CNT
Counter register
Counter overflow
1F
Update event(UEV)
20
00
Update interrupt flag(UDITF)
Internal clock
divided by N
Internal clock
divided by 2