TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual 24-42 V2.0, 2007-07
GPTA, V2.0
Comparison Between Unsigned and Signed Compare
To be able to support different timer periods and to support correct observation even
beyond timer overflow, the GPTA embeds the scalable and signed greater/equal
comparator. Using a signed comparison allows one overflow of the timer to occur within
the observation window. This is illustrated in Figure 24-29.
Using a signed compare in order to take into account the timer overflow, the comparator
window is introduced. The comparator window is centered to the point T and its width
can be selected by the user.
Figure 24-29 Unsigned Versus Signed Compare
When the timer range is a multiple of 2 and because the comparator is scalable, the
observation window and the comparator window are identical. See Figure 24-30.
MCT05938
Unsigned
Compare
T
BA
T
BA
T
BA
Signed
Compare
T
BA
T
BA
T
BA
T: Threshold
B: Before
A: After
Ideal case where the timer period is a power of 2
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