AN2897 Freescale Semiconductor / Motorola, AN2897 Datasheet - Page 19

• Manufacturer Part Number: AN2897
• Description: Using the eTPU Angle Clock
• Manufacturer: Freescale Semiconductor / Motorola

4.2
Table
Reference Design. The states are referenced in the following description of an angle clock system
implementation.
Freescale Semiconductor
1shows a simplified state table for an Angle Clock system, similar to the implementation in the
InitializeCrank
First_edge
First Period
Testing_Possible_Gap StallTimer = StallPeriod at startpoint Time(activeEdge)
Apparent_Gap
State Machine Description
Reference
Name
TICKS = TicksPerToot - 1
ToothCount = 0
CrankStatus = Stall;
CrankStatus = WaitingGap
StallTimer = StallPeriod at startpoint Time(activeEdge)
ToothTime = Time(ActiveEdge)
StallTimer = StallPeriod at startpoint Time(activeEdge)
Period = Time(ActiveEdge) - ToothTime
ToothTime = Time(ActiveEdge)
ToothCount += 1
TickRate = Period/TicksPerTooth
BlankTimer = Period * BlankingRatio
PeriodLast = Period
Period = Time(ActiveEdge) - ToothTime
ToothTime = Time(ActiveEdge)
ToothCount += 1
TickRate = Period/TicksPerTooth
BlankTimer = Period * BlankingRatio
Period = PeriodLast
TickRate = Period/TicksPerTooth
Table 1. Angle Clock System State
Using the eTPU Angle Clock, Rev. 0
Action
If ActiveEdge
If timeout (StallTimer)
If ActiveEdge
If ActiveEdge
If timeout (StallTimer)
If Period>GapRatio *
PeriodLast
If ActiveEdge
If timeout (StallTimer)
If ActiveEdge
If timeout (StallTimer)
Exit Condition
eTPU Software Design
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