General-purpose timers (TIM2/TIM3/TIM4/TIM5) RM0440
1286/2126 RM0440 Rev 4
Figure 419. Index behavior in x1 and x2 mode (IPOS[1:0] = 01)
Directional index sensitivity
The IDIR[1:0] bitfield in the TIMx_ECR register allows the index to be active only in a
selected counting direction.
The Figure 420 below shows the relationship between index and counter reset events,
depending on IDIR[1:0] value.
Note: The IDR[1:0] bitfield must be written when IE bit is reset (index mode disabled).
Note: The directional index sensitivity is not supported in clock + direction mode. When
SMS[3:0] = 1010 or 1011, the IDIR[1:0] must be set to 00.
MSv45773V1
Channel A
Channel B
DIR bit
Index
Counter x1
5 6 7 0 1
3
Counter x2 10 11 0 1 2 1 0 11 10 9 8
AB = IPOS[1:0] = 01