Texas Instruments TMS570LC4357 - Page 1939

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
www.ti.com Application of the ECAP Module
1939
SPNU563A–March 2018
Submit Documentation Feedback
Copyright © 2018, Texas Instruments Incorporated
Enhanced Capture (eCAP) Module
33.3.2 Example 2 - Absolute Time-Stamp Operation Rising and Falling Edge Trigger
In Figure 33-10, 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 33-10. Capture Sequence for Absolute Time-stamp With Rising and Falling Edge Detect