ST STM32F40 Series Reference Manual page 520

RM0090
Bit 2 OC1FE: Output compare 1 fast enable
Bits 1:0 CC1S: Capture/Compare 1 selection
Note: CC1S bits are writable only when the channel is OFF (CC1E = 0 in TIMx_CCER).
Input capture mode
Bits 15:8 Reserved, must be kept at reset value.
Bits 7:4 IC1F: Input capture 1 filter
This bit-field defines the frequency used to sample TI1 input and the length of the digital filter
applied to TI1. The digital filter is made of an event counter in which N events are needed to
validate a transition on the output:
0000: No filter, sampling is done at f
0001: f
0010: f
0011: f
0100: f
0101: f
0110: f
0111: f
Note: In current silicon revision, f
Bits 3:2 IC1PSC: Input capture 1 prescaler
This bit-field defines the ratio of the prescaler acting on CC1 input (IC1).
The prescaler is reset as soon as CC1E='0' (TIMx_CCER register).
00: no prescaler, capture is done each time an edge is detected on the capture input
01: capture is done once every 2 events
10: capture is done once every 4 events
11: capture is done once every 8 events
Bits 1:0 CC1S: Capture/Compare 1 selection
This bit-field defines the direction of the channel (input/output) as well as the used input.
00: CC1 channel is configured as output
01: CC1 channel is configured as input, IC1 is mapped on TI1
10: Reserved
11: Reserved
Note: CC1S bits are writable only when the channel is OFF (CC1E = 0 in TIMx_CCER).
This bit is used to accelerate the effect of an event on the trigger in input on the CC output.
0: CC1 behaves normally depending on counter and CCR1 values even when the trigger is
ON. The minimum delay to activate CC1 output when an edge occurs on the trigger input is
5 clock cycles.
1: An active edge on the trigger input acts like a compare match on CC1 output. OC is then
set to the compare level independently of the result of the comparison. Delay to sample the
trigger input and to activate CC1 output is reduced to 3 clock cycles. OC1FE acts only if the
channel is configured in PWM1 or PWM2 mode.
This bit-field defines the direction of the channel (input/output) as well as the used input.
00: CC1 channel is configured as output.
01: CC1 channel is configured as input, IC1 is mapped on TI1.
10:
11:
=f
SAMPLING CK_INT
=f
SAMPLING CK_INT
=f
SAMPLING CK_INT
=f /2, N=61100: f
SAMPLING DTS
=f /2, N=81101: f
SAMPLING DTS
=f /4, N=61110: f
SAMPLING DTS
=f /4, N=81111: f
SAMPLING DTS
2 or 3.
Doc ID 018909 Rev 4
General-purpose timers (TIM9 to TIM14)
1000: f
DTS SAMPLING
, N=21001: f =f
SAMPLING DTS
, N=41010: f =f
SAMPLING DTS
, N=81011: f =f
SAMPLING DTS
=f
SAMPLING DTS
=f
SAMPLING DTS
=f
SAMPLING DTS
=f
SAMPLING DTS
is replaced in the formula by CK_INT when ICxF[3:0]= 1,
DTS
=f /8, N=6
DTS
/8, N=8
/16, N=5
/16, N=6
/16, N=8
/32, N=5
/32, N=6
/32, N=8
520/1422