Information

channel (n) input
(after the filter
DECAPEN bit
C(n+1)V
FTM counter
clear CH(n+1)F
problem 1 problem 2
2
1
2
3
channel input)
DECAP bit
set DECAPEN
set DECAP
5
6
7
8
10
3
4 6
5
Note
- The commands set DECAPEN, set DECAP, clear CH(n)F, and clear CH(n+1)F are made by the user.
4
9
11
12
13
14
9
10
7
8
15
16
17
18
19
20
21
22
23
24
25
26
27
28
15
16
19
20
22
24
- Problem 1: channel (n) input = 1, set DECAP, not clear CH(n)F, and clear CH(n+1)F.
- Problem 2: channel (n) input = 1, set DECAP, not clear CH(n)F, and not clear CH(n+1)F.
C(n)V
CH(n+1)F bit
CH(n)F bit
clear CH(n)F
1
Figure 37-245. Dual Edge Capture – One-Shot Mode for Positive Polarity Pulse Width
Measurement
The following figure shows an example of the dual edge capture – continuous mode used
to measure the positive polarity pulse width. The DECAPEN bit selects the dual edge
capture mode, so it keeps set in all operation mode. While the DECAP bit is set the
configured measurements are made. The CH(n)F bit is set when the first edge of the
positive polarity pulse is detected, that is, the edge selected by ELS(n)B:ELS(n)A bits.
The CH(n+1)F bit is set when the second edge of this pulse is detected, that is, the edge
selected by ELS(n+1)B:ELS(n+1)A bits. The CH(n+1)F bit indicates when two edges of
the pulse were captured and the C(n)V and C(n+1)V registers are ready for reading.
Chapter 37 FlexTimer (FTM)
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 995