AN4300 datasheet(37/40 Pages) STMICROELECTRONICS

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DocID024675 Rev 2

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AN4300

Conclusion

The SPC56EC74 lighting application example introduces MCU eMIOS, CTU, and ADC

modules usage within a lighting application, which is in this case well suited for the lamp

light bulbs control as well as for the lamp LEDs control with no major change required in the

peripheral’s software.

The benefit of using the CTU module is significant as opposed to using the timer to trigger

ADC at a certain point within a PWM channel cycle. The timer produces frequent interrupts

that need to be processed by the MCU CPU, causing an increase in the CPU load and

suspending run time processes. Using the CTU gives the application designer a powerful

tool to avoid diagnostic timer-configuration challenges and makes the lighting application

simpler to design and test.

The ADC module gives the designer the opportunity to use watchdog threshold interrupts to

increase MCU performance, and enables fast responses in case of lamp light bulb failures.

If required, the number of the ADC channels can be increased from 64 up to 95, using

simple external logic circuitry fully controlled by the ADC module.

The eMIOS module offers up to 64 PWM channels suitable for a lighting application as well

as for other PWM-based applications. The eMIOS module provides PWM channels with

high resolution and flexibility.

The lighting application example consists of an example description and complete software

demonstration based on the SPC56EC74L7 LQFP176 minimodule and EVB.

This example is easily portable to each device of the SPC56xB/Cxx family; for devices

which have DMA module, no particular modifications are required. For devices where DMA

module is missing, the DMA feature can be replaced with interrupt routines but with a higher

CPU load.

AN4300 Datasheet(PDF) 37 Page - STMicroelectronics