CEVT1
CEVT2
CEVT3
CEVT4
CEVT1
FFFFFFFF
CTR[0−31]
00000000
CAPx pin
t
MOD4
CTR
CAP1
CAP2
CAP3
CAP4
Capture registers [1−4]
CEVT2
CEVT1
CEVT3
CEVT4
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
0
1
2
3
0
1
2
3
0
XX
t
1
t
5
XX
t
2
t
6
XX
t
3
t
7
XX
t
4
t
8
Polarity selection
t
Enhanced Capture (eCAP) Module
15.3.3.2 Absolute Time-Stamp Operation Rising and Falling Edge Trigger Example
In
the eCAP operating mode is almost the same as in the previous section except capture
events are qualified as either rising or falling edge, this now gives both period and duty cycle information:
Period1 = t
3
– t
1
, Period2 = t
5
– t
3
, …etc. Duty Cycle1 (on-time %) = (t
2
– t
1
) / Period1 x 100%, etc. Duty
Cycle1 (off-time %) = (t
3
– t
2
) / Period1 x 100%, etc.
Figure 15-110. Capture Sequence for Absolute Time-Stamp, Rising and Falling Edge Detect
1621
SPRUH73H – October 2011 – Revised April 2013
Pulse-Width Modulation Subsystem (PWMSS)
Copyright © 2011–2013, Texas Instruments Incorporated