General-purpose timers (TIM2/TIM3/TIM4) RM0444
670/1390 RM0444 Rev 5
22.4 TIM2/TIM3/TIM4 registers
Refer to Section 1.2 for a list of abbreviations used in register descriptions.
The peripheral registers can be accessed by half-words (16-bit) or words (32-bit).
22.4.1 TIMx control register 1 (TIMx_CR1)(x = 2 to 4)
Address offset: 0x00
Reset value: 0x0000
1514131211109876543210
Res. Res. Res. Res.
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
Bits 15:12 Reserved, must be kept at reset value.
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 (CK_INT) frequency and
sampling clock used by the digital filters (ETR, TIx),
00: t
DTS
= t
CK_INT
01: t
DTS
= 2 × t
CK_INT
10: t
DTS
= 4 × t
CK_INT
11: Reserved
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)
Bit 4 DIR: Direction
0: Counter used as upcounter
1: Counter used as downcounter
Note: This bit is read only when the timer is configured in Center-aligned mode or Encoder
mode.
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