RM0440 Rev 4 1175/2126
RM0440 Advanced-control timers (TIM1/TIM8/TIM20)
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28.6 TIM1/TIM8/TIM20 registers
Refer to Section 1.2 for a list of abbreviations used in register descriptions.
28.6.1 TIMx control register 1 (TIMx_CR1)(x = 1, 8, 20)
Address offset: 0x000
Reset value: 0x0000
1514131211109876543210
Res. Res. Res.
DITH
EN
UIFRE
MAP
Res. CKD[1:0] ARPE CMS[1:0] DIR OPM URS UDIS CEN
rw rw rw rw rw rw rw rw rw rw rw rw
Bits 15:13 Reserved, must be kept at reset value.
Bit 12 DITHEN: Dithering enable
0: Dithering disabled
1: Dithering enabled
Note: The DITHEN bit can only be modified when CEN bit is reset.
Bit 11 UIFREMAP: UIF status bit remapping
0: No remapping. UIF status bit is not copied to TIMx_CNT register bit 31.
1: Remapping enabled. UIF status bit is copied to TIMx_CNT register bit 31.
Bit 10 Reserved, must be kept at reset value.
Bits 9:8 CKD[1:0]: Clock division
This bit-field indicates the division ratio between the timer clock (tim_ker_ck) frequency and
the dead-time and sampling clock (t
DTS
)used by the dead-time generators and the digital
filters (tim_etr_in, tim_tix),
00: t
DTS
=t
tim_ker_ck
01: t
DTS
=2*t
tim_ker_ck
10: t
DTS
=4*t
tim_ker_ck
11: Reserved, do not program this value
Bit 7 ARPE: Auto-reload preload enable
0: TIMx_ARR register is not buffered
1: TIMx_ARR register is buffered
Bits 6:5 CMS[1:0]: Center-aligned mode selection
00: Edge-aligned mode. The counter counts up or down depending on the direction bit
(DIR).
01: Center-aligned mode 1. The counter counts up and down alternatively. Output compare
interrupt flags of channels configured in output (CCxS=00 in TIMx_CCMRx register) are
set only when the counter is counting down.
10: Center-aligned mode 2. The counter counts up and down alternatively. Output compare
interrupt flags of channels configured in output (CCxS=00 in TIMx_CCMRx register) are
set only when the counter is counting up.
11: Center-aligned mode 3. The counter counts up and down alternatively. Output compare
interrupt flags of channels configured in output (CCxS=00 in TIMx_CCMRx register) are
set both when the counter is counting up or down.
Note: It is not allowed to switch from edge-aligned mode to center-aligned mode as long as
the counter is enabled (CEN=1)