Microcontrollers optimise automotive light management

Article By : STMicroelectronics

The interconnection of SPC56EC74's eMIOS, CTU and ADC modules within a lighting application will not place an additional load on the CPU.

In an automotive lighting application, you can use two types of lights: the incandescent lamp and LED. SPC56xBx and SPC56xCx are high performance microcontrollers for car body applications. These are used in automotive light management and to assist the car body system developer in writing optimised firmware with a very low CPU load.

In a typical system solution for a light application, the SPC56xB/Cx microcontroller can manage several power drivers, depending on how the power is managed and the number of channels to be driven. Some devices are driven by an SPI link. Using this link, the application can configure the signals that are generated inside the driver device, to drive the loads.

The interconnection of the eMIOS, CTU and ADC modules of the SPC56EC74 (a member of the SPC56xB/Cx family) within a lighting application, will not place an additional load on the CPU.

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 64PWM 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.

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