NXP Semiconductors MPC5644A, Reference Manual, Page: 129 / 1735

Device Performance Optimization
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 129
Table 6-7. Performance optimization checklist—Part 3. Peripherals and general application guidelines
Peripherals and general application guidelines
Use eDMA rather than the core to move data where possible. Most peripherals can generate eDMA requests to shift
data.
• Use eDMA to control movement of commands and results from ADC and to maintain circular buffers in system
memory.
• Create circular buffers so that ADC results can be stored in RAM with no core overhead.
Shift loading from the CPU to the eTPU2 whenever possible.
• The eTPU2 can provide effective CPU off-loading for time and angle based operations.
• The eTPU2 can trigger the ADC directly with no need for CPU interruption.
Avoid software polling and allow peripherals to trigger interrupts or request eDMA servicing.
• Use hardware instead of software vectored interrupts to reduce latency.
• Trigger eDMA requests rather than interrupting the CPU to move data/results.
Configure the external memory interface.
• Enable bursting on the external bus.
• Reduce external bus wait states from default maximum settings.
• Place time critical functions in internal memory.
• Small, but frequently executed routines can be considered as candidates to be locked in cache.