HET[2]
ext. ref.
signal
APCNT
period
counter
DCF
Decel
flag
ACNT
angle
generator
Singularity
GPF
Gap flag
Gap End
Gap Start
Angle Functions
993
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
High-End Timer (N2HET) Module
23.3.1.1 Singularities
Singularities (gaps, in this case, from missing teeth in a toothed wheel) in the external reference signal
can be masked. The start and end of singularities are defined by gap start and gap end values specified in
SCNT and ACNT. When ACNT reaches gap start or gap end, it sets/resets the gap flag.
While the gap flag is set, new periods of the external reference signal are ignored for angle computation.
SCNT uses the last period measured by APCNT just before gap start.
and
illustrate the behavior of the angle generator during a gap after a
deceleration or acceleration of the N2HET.
Figure 23-33. N2HET Timings Associated with the Gap Flag (ACNT Deceleration)