The course serves as a foundation for the Eat-Sleep-Code-Repeat learning initiative, encouraging a hands-on approach where students continuously learn, develop, test, and improve automotive embedded applications using real hardware and practical examples.

The course serves as a foundation for the Eat-Sleep-Code-Repeat learning initiative, encouraging a hands-on approach where students continuously learn, develop, test, and improve automotive embedded applications using real hardware and practical examples.

1. Overview   This module demonstrates how to implement a steering control system using Pulse Width Modulation (PWM) on NXP S32K3 microcontrollers. The application reads an analog input from a potentiometer (simulating a steering wheel) and converts it into a servo motor position. As the input changes, the servo motor reacts in real time, mimicking how steering systems work in modern vehicles. This example is based on Application Code Hub demonstrations for: PWM-Based Steering Control for FRDM-A-S32K344 PWM-Based Steering Control for FRDM-A-S32K312 In this workshop, a POT Click simulates the steering wheel position. When the student rotates it, an analog voltage proportional to the angle is read by the MCU through the ADC, scaled in software, and converted into a PWM duty cycle. The PWM is generated by the Servo Click (configured by the MCU over I²C) and drives a Micro Servo motor SG 180°, whose angle tracks the potentiometer in real time. Beyond the technical implementation, the course serves as a foundation for the Eat-Sleep-Code-Repeat learning initiative, encouraging a hands-on approach where students continuously learn, develop, test, and improve automotive embedded applications using real hardware and practical examples.   2. Learning Scope   After completing this course, participants should be able to:   Understand a basic steering control system and the ideas behind EPS and steer-by-wire. Use the POT Click as a simulated steering-wheel input. Acquire analog values (0–3.3 V) using the ADC and understand analog-to-digital conversion. Perform signal scaling from the ADC range to a servo angle / PWM duty cycle. Generate PWM signals to drive a servo motor. Configure the Servo Click over I²C using the OE (Output Enable) pin. Recognize the actuation data flow: sensor input → MCU processing → PWM actuation. Import, build, flash, and debug an ACH project in S32 Design Studio 3.6.5. Understand why steering functions are relevant for functional safety. 3. System Architecture   The three elements capture exactly the basic idea of the system in the demo: Input: Potentiometer (POT Click simulates the steering-wheel position) Processing: S32K3 MCU (reads the ADC, scales the value, commands the actuator) Output: Servo motor controlled via PWM (Micro Servo SG 180°) This matches the classic flow of an embedded actuation system: sensor → processing → actuator. Functional Flow The system operates continuously as follows: The potentiometer generates an analog voltage based on its position The ADC converts this voltage into a digital value The application scales this value into a steering angle The system generates a PWM signal based on the angle The servo motor moves accordingly This loop runs continuously to ensure real-time control. Steering Monitoring Application Architecture 4. Key Concepts   4.1 ADC (Analog-to-Digital Converter) The POT Click outputs 0–3.3 V depending on the wiper position. The ADC samples this voltage at regular intervals and quantizes it into a digital code (a 12-bit ADC produces values between 0 and 4095). The further the potentiometer is turned, the higher (or lower) the digital sample. ADC acquisition is the foundation of automotive sensing — used for torque, throttle, battery voltage, and many others. 4.2 Signal Scaling — From ADC to Servo Angle The ADC range (for example 0–4095) and the servo range (0°–180°, expressed as a PWM duty cycle) are different. The application performs a linear mapping so that one end of the potentiometer corresponds to one steering extreme and the other end to the opposite. This is the same scaling used in real EPS systems, where a hardware reading is converted into a normalized control command. 4.3 PWM — Pulse-Width Modulation and Servo Control PWM switches a digital output on and off at a fixed frequency, varying the duty cycle (the fraction of time the signal is high). A hobby servo such as the SG 180° interprets this duty cycle as a position command. In this demo, the PWM is not generated by the MCU itself but by the Servo Click's dedicated PWM controller, which the MCU configures over I²C — a typical embedded pattern that offloads time-critical signal generation and keeps the CPU free for application logic. 4.4 I²C — Configuring the Servo Click I²C — Inter-Integrated Circuit is a two-wire serial bus made of SDA (data) and SCL (clock). The S32K3 uses LPI2C1 on PTC6 (SDA) and PTC7 (SCL) to configure the Servo Click — PWM frequency, channel, and duty cycle. The OE — Output Enable pin on PTB17 is an additional control line that enables or disables the PWM outputs without reconfiguring the chip, which is also useful for a quick "safe stop" behavior. 4.5 POT Click as Steering Wheel The POT Click is a simplified, safe stand-in for a real steering sensor. The student rotates it by hand, the voltage changes, the MCU reads it through the ADC, scales it, and the servo reacts. 4.6 Data Flow at a Glance Physical rotation → analog voltage → ADC sample → scaled command (angle / duty cycle) → I²C configuration of the Servo Click → PWM signal → servo angle. This direct chain from the student's hand to the servo shaft is the main educational value of the demo. 5. Hardware and Software Setup   Required Hardware Component Image Purpose FRDM-A-S32K312 Alternative MCU platform used to run the steering application and process steering inputs. FRDM-A-S32K344 Alternative MCU platform used to run the steering application and control connected peripherals. FRDM-K64 Click Shield mikroBUS expansion board used to connect Click modules to the FRDM platform. Servo Click PWM driver board used to control the servo motor position. POT Click   Potentiometer module used to simulate steering wheel input. Micro Servo SG 180°                     Actuator used to convert control signals into steering movement. USB-C / 12 V supply — Provides power and enables programming and debugging of the system.   The example applications demonstrate how these peripherals are connected to the MCU pins and used to simulate steering wheel input and actuator control.   Steering Control Monitoring on FRDM-A-S32K312 Steering Control Monitoring on FRDM-A-S32K344       Software Environment S32 Design Studio IDE S32K3 Automotive Software Package Application Code Hub project import PWM-Based Steering Control for FRDM-A-S32K344 PWM-Based Steering Control for FRDM-A-S32K312 6. Implementation Guide   Step Action Sub-steps Expected Result 1 Import the Project Open S32 Design Studio Select “Import project from Application Code Hub” Search for the steering demo Use the GitHub link for automatic configuration Select main branch Import project Project successfully appears in workspace 2 Build the Application Right-click project Select “Update Code and Build Project” Confirm SDK component management Build completes with no errors and generates .elf file 3 Connect Hardware Connect USB cable (and 12V supply for S32K312) Attach click boards Verify wiring Board is powered and detected by IDE 4 Flash and Run Open Debug Configurations Select “debug_flash_pemicro” Start debugging Application runs continuously 5 Functional Validation Rotate the potentiometer Observe servo movement Servo follows potentiometer position in real time   7. Signal Behavior and Control Logic     Figure: Steering control signal mapping. The 12-bit ADC value (0–4095) is linearly mapped to a servo angle (0°–180°) and a matching PWM duty cycle (1.0–2.0 ms), with reference points at Left, Center and Right. At startup the servo moves to the neutral position; during operation, any input change produces an immediate, proportional reaction — implementing a basic steer-by-wire behavior.   8. Troubleshooting   Issue Possible Actions Board Not Detected Check USB cable and drivers Verify debugger connection Restart IDE No Servo Movement Verify PWM configuration Check servo wiring Ensure correct power supply Incorrect Behavior Check ADC configuration Validate scaling function Ensure PWM duty cycle mapping is correct Unstable Movement Add signal filtering Check power stability   9. Extending the Application   The basic implementation can be extended in several ways: Steering Range Control Restrict or extend the actuator's range of motion Define software-based limits to protect the mechanics Input Direction Inversion Reverse how the actuator responds to the input Useful for left-hand vs. right-hand drive calibration Noise Filtering Apply software filtering to stabilize readings Avoid jitter near the center position Scaling Logic Exploration Identify and analyze how the input is mapped to the output Connect software math with hardware behavior Fault-Handling Behavior Add a mechanism that reacts to a detected fault Transition the system into a safer state State Machine Implementation A more advanced approach is to implement a state machine: Idle Active Fault 10. Safety Context   This example reflects key automotive principles: Continuous monitoring of driver input Immediate response to control signals Reliable actuator control In real systems: Redundancy is required Fault detection mechanisms are implemented Systems must comply with ISO 26262 (functional safety standard) Steer-by-wire systems require high reliability since there is no direct mechanical link. 11. Conclusion   This module demonstrates how a simple embedded system can implement steering control using ADC input and PWM output. It shows how: Analog input is acquired Data is processed in real time Actuators are controlled using PWM   Result on FRDM-A-S32K312 Result on FRDM-A-S32K344   The course provides a strong foundation for more advanced systems, including filtering, state machines, and safety-oriented designs.

The course serves as a foundation for the Eat-Sleep-Code-Repeat learning initiative, encouraging a hands-on approach where students continuously learn, develop, test, and improve automotive embedded applications using real hardware and practical examples.