3
9
4
13
6
HET
Res.
Angle
increment
HET
counter
10
Compare
value
When the HET counter passes from 9 to 13, the equality compare can not
match the compare value 10. Consequently, the angle position is missed!
9
10
11
12
13
14
15
16
3
9
4
13
Angle
counter
HET
Res.
Angle
increment
HET
counter
6
CNT position in the loop
Angle Functions
845
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
High-End Timer (N2HET) Module
When the engine speed increases, the angle count can increment by more than one in a NHET resolution
but the HWAG will continue to provide the angle increment value at every resolution..
The NHET can then implement its own angle counter (using a CNT instruction in angle mode) which will
be incremented once per resolution by the value given by the angle increment. For an example of an
angle count within the NHET with increments, see
.
Figure 20-52. Angle Count Within the NHET With Increments
20.3.2.4.2 NHET Operation on Angle Functions (ACMP, CNT)
20.3.2.4.2.1 State of the Art
Because the angle value can be increased by more than one, the compare value could be in-between the
old angle value and the new angle value of the NHET angle counter (where new angle value = old angle
value + angle increment). To perform an angle compare that ensures not to miss a compare value, the
NHET provides the ACMP instruction. For an example of a compare without ACMP instruction, see
.
Figure 20-53. Compare Without ACMP Instruction