General-purpose timers (TIM2/TIM3/TIM4)
RM0365
613/1080
DocID025202 Rev 7
21.4.11 TIMx
prescaler
(TIMx_PSC)
Address offset: 0x28
Reset value: 0x0000
21.4.12 TIMx auto-reload register (TIMx_ARR)
Address offset: 0x2C
Reset value: 0xFFFF FFFF
Bit 31 Value depends on IUFREMAP in TIMx_CR1.
If UIFREMAP = 0
CNT[31]
: Most significant bit of counter value (on TIM2 )
Reserved on other timers
If UIFREMAP = 1
UIFCPY
: UIF Copy
This bit is a read-only copy of the UIF bit of the TIMx_ISR register
Bits 30:16
CNT[30:16]
: Most significant part counter value (on TIM2 )
Bits 15:0
CNT[15:0]
: Least significant part of counter value
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PSC[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 15:0
PSC[15:0]
: Prescaler value
The counter clock frequency CK_CNT is equal to f
CK_PSC
/ (PSC[15:0] + 1).
PSC contains the value to be loaded in the active prescaler register at each update event
(including when the counter is cleared through UG bit of TIMx_EGR register or through
trigger controller when configured in “reset mode”).
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
ARR[31:16] (depending on timers)
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ARR[15:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:16
ARR[31:16]
: High auto-reload value (on TIM2 )
Bits 15:0
ARR[15:0]
: Low Auto-reload Prescaler value
ARR is the value to be loaded in the actual auto-reload register.
Refer to the
Section 21.3.1: Time-base unit on page 552
for more details about ARR update
and behavior.
The counter is blocked while the auto-reload value is null.