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Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
987
To find the WCL for channel 0, assume channel 0 has just finished service. Map the channels in the
H-M-H-L-H-M-H sequence. See
.
Figure 24-73. Worst-case latency for channel 0 (second try)
Conclusion: with this system configuration, the WCL of both channel 0 and channel 1 is 3.85 ms, which
is within the limit of 4 ms needed for a 50-kHz PWM.
Next, find the WCL for channel 2. Assume channel 2 has just finished service. Map the channels in the
H-M-H-L-H-M-H sequence. See
.
Figure 24-74. Worst-case latency for channel 2
Conclusion: with this system configuration, the WCL for channels 2 and 8 is 4.7 ms, which is within the
40 and 80 ms WCL requirements.
Table 24-126. Second-Try system configuration
Channel
Priority
Function
1
,
2
1
0% RAM collision rate
2
CPU clock rate = 40 MHz, or 60 ns per clock period
0
High
PWM at 50 kHz (needs a 4-µs WCL)
1
High
PWM at 50 kHz (needs a 4-µs WCL)
2
Middle
PWM at 5 kHz (needs a 40-µs WCL)
8
Middle
PPWA at 5 kHz (needs an 80-µs WCL)
15
Low
DIO as input at rate of 1 ms
TPU CH0 WCL TIM 2
TPU CH0 WCL TIM 2
= 10-CYCLE TIME SLOT TRANSITION
= 4-CYCLE NOP INSTRUCTION
CHANNEL 0
SERVICED
WORST CASE LATENCY
H
M
H
L
H
M
H
H
CHANNEL 2
OR CHANNEL
SERVICED
CHANNEL 1
SERVICED
CHANNEL 15
SERVICED
CHANNEL 0
SERVICED
M
H
L
TPU CH2 WCL TIM 1
TPU CH2 WCL TIM 1
= 10-CYCLE TIME SLOT TRANSITION
= 4-CYCLE NOP INSTRUCTION
CHANNEL 2
SERVICED
WORST CASE LATENCY
H
M
H
L
H
M
H
H
CHANNEL 0
SERVICED
CHANNEL 15
SERVICED
CHANNEL 1
SERVICED
CHANNEL 8
SERVICED
M
H
L
CHANNEL 2
SERVICED
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...