TC1796
Peripheral Units (Vol. 2 of 2)
General Purpose Timer Array (GPTA)
User’s Manual
24-45
V2.0, 2007-07
GPTA, V2.0
A comparison of the previous figures shows that the position of the observation window
with respect to T is dependent on the value of T itself. That means the user, before
updating the comparator with T, needs to calculate the observation window as a function
of T. To avoid this calculation, a
core observation window
can be defined that is
independent of T. It will always be centered on T, whatever its value is. However, one
particularity exists when using the core observation window: the size of the core
observation window varies depending on two static values: the timer period and the
comparator window’s sizes. In particular, the core observation window reduces as the
value of the timer period is just after a power of 2. This is shown in
For any timer period (whatever the range) and any threshold position, a symmetrical core
observation window of a statically defined size can be determined.
Figure 24-33 The Core Observation Window
MCT05942
Core Observation Window
T
Before After
Comparator Window = 2 × 2
k
Period is not a power of 2
M
m
Period = M - m + 1
