Advanced-control timers (TIM1&TIM8)
RM0090
554/1731
DocID018909 Rev 11
17.4 TIM1&TIM8
registers
Refer to
Section: List of abbreviations for registers
for a list of abbreviations used in register
descriptions.
The peripheral registers must be written by half-words (16 bits) or words (32 bits). Read
accesses can be done by bytes (8 bits), half-word (16 bits) or words (32 bits).
17.4.1 TIM1&TIM8
control
register 1 (TIMx_CR1)
Address offset: 0x00
Reset value: 0x0000
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
CKD[1:0]
ARPE
CMS[1:0]
DIR
OPM
URS
UDIS
CEN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 15:10 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 the
dead-time and sampling clock (t
DTS
)used by the dead-time generators and 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, 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)
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.
Bit 3
OPM
: One pulse mode
0: Counter is not stopped at update event
1: Counter stops counting at the next update event (clearing the bit CEN)