MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
713
Preliminary—Subject to Change Without Notice
NOTE
MCB and OPWFMB modes have a different behavior.
Figure 22-83. Time base period when running in the fastest prescaler ratio
If the prescaler ratio is greater than one or external clock is selected, the counter may behave in three
different ways depending on the channel mode:
•
If MC mode and Clear on Match Start and External Clock source are selected the internal counter
behaves as described in
.
•
If MC mode and Clear on Match Start and Internal Clock source are selected the internal counter
behaves as described in
.
•
If MC mode and Clear on Match End are selected the internal counter behaves as described in
.
•
If OPWFM mode is selected the internal counter behaves as described in
. The
internal counter clears at the start of the match signal, skips the next prescaled clock edge and then
increments in the subsequent prescaled clock edge.
NOTE
MCB and OPWFMB modes have a different behavior.
system clock
input event/prescaler clock enable = 1
internal counter
match value = 3
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
PRE SCALED CLOCK RATIO = 1
(bypassed)
see note 1
FLAG set event
Note 1: When a match occurs, the first clock cycle is used to
clear the internal counter, starting another period.
FLAG pin/register
FLAG clear