PXR40RM Datasheet, PDF (807/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Enhanced Modular Input/Output Subsystem (eMIOS200)
PRESCALED CLOCK RATIO = 1 (Bypassed)
Clock
Prescaled Clock = 1
See Note
Internal Counter 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3
Match Value = 3
Note: When a match occurs, the first clock cycle is used to clear the internal counter,
starting another period.
Figure 23-61. 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 Figure 23-63.
• If MC mode and Clear on Match Start and Internal Clock source are selected the internal counter
behaves as described in Figure 23-64.
• If MC mode and Clear on Match End are selected the internal counter behaves as described in
Figure 23-65.
• If OPWFM mode is selected the internal counter behaves as described in Figure 23-64. 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.
PRESCALED CLOCK RATIO = 3
Clock
Prescaled Clock
Internal Counter
1
2
30
0
1
2
30
0
Match Value = 3
See Note
Note: When a match occurs, the first clock cycle is used to clear the internal counter, and only
after a second edge of prescaled clock the counter will start counting.
Figure 23-62. Time Base Period when Running with a Prescaler Ratio Greater Than 1
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
23-67