MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
17-66 Freescale Semiconductor
Figure 17-54. eMIOS Time Base Generation Block Diagram
Figure 17-55. eMIOS Time Base Example — Fastest Prescaler Ratio
Figure 17-56. eMIOS Time Base Example — Prescale Ratio = 3, Match Value = 3
Global Prescaler
GPRENGPRE
System
Clock Prescaler
UCPRENUCPRE
Ratio = (GPRE + 1) (UCPRE + 1)
Prescaled Clock
CCNTRn
Internal Counter
Match Signal
Match Value
Clock
Prescaled Clock
(Ratio = 1 (Bypassed))
1 230 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3
NOTE: The period of the time base includes the match value. When a match occurs, the first
clock cycle is used to clear the internal counter, starting another period
Clock
See Note
Match Value = 3
Internal Counter
EMIOS_CCNTRn
Prescaled Clock
Internal Counter
1 2 0 3
NOTE: The period of the time base does not include the match value. When a match occurs,
the first clock cycle is used to clear the internal counter, starting another period
Clock
See Note
3 1 2 3 0 1 2
EMIOS_CCNTRn
(Ratio = 3)
Match Value = 3
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