STM32 Mbed CodeIDE (8/8): integrated controller capstone

The controller uses one potentiometer as a measured level and one button as an acknowledge control.

Hardware map used by the starter controller:

- PC_1 is the analog level input, controlled by the Pot. pot2 slider.
- PC_5 is the acknowledge button input, controlled by the B1 button.
- PA_8, PA_9, and PA_10 are the RGB PWM channels.
- PB_13 is the active-low green status LED.

Read this map as a set of Mbed objects working together: AnalogIn reads the level, DigitalIn reads the acknowledge button, PwmOut drives the RGB channels, and DigitalOut drives the status LED. The capstone is mainly about connecting those API pieces into one readable controller.

The required behavior is:

- Level below 40%: RGB output green, status LED off, serial evidence like
percent=25 level=SAFE ack=0.
- Level from 40% to 69%: RGB output yellow, status LED off, serial evidence like
percent=55 level=WARNING ack=0.
- Level 70% or higher with the button released: RGB output red, status LED
blinking, serial evidence like percent=80 level=CRITICAL ack=0. Watch
for at least two seconds before recording this state; count it as blinking
only if the status LED turns on and off repeatedly.
- Level 70% or higher with the button pressed: RGB output blue, status LED off,
serial evidence like percent=80 level=CRITICAL ack=1.

The acknowledge button does not make the critical level safe. It only changes the visible warning so the operator can show that the alarm has been noticed.

#include "mbed.h"

AnalogIn level_control(PC_1);
DigitalIn acknowledge_button(PC_5, PullUp);

PwmOut rgb_red(PA_8);
PwmOut rgb_green(PA_9);
PwmOut rgb_blue(PA_10);

DigitalOut status_led(PB_13, 1);

void status_on() {
    status_led = 0;
}

void status_off() {
    status_led = 1;
}

void set_rgb(float red, float green, float blue) {
    rgb_red.write(red);
    rgb_green.write(green);
    rgb_blue.write(blue);
}

void show_safe() {
    set_rgb(0.0f, 0.7f, 0.0f);
    status_off();
}

void show_warning() {
    set_rgb(0.7f, 0.5f, 0.0f);
    status_off();
}

void show_critical(bool acknowledged) {
    if (acknowledged) {
        set_rgb(0.0f, 0.0f, 0.8f);
        status_off();
    } else {
        set_rgb(0.9f, 0.0f, 0.0f);
        status_led = !status_led.read();
    }
}

int main() {
    rgb_red.period_ms(2);
    rgb_green.period_ms(2);
    rgb_blue.period_ms(2);

    printf("Integrated controller start\n");

    while (true) {
        float reading = level_control.read();
        int percent = (int)(reading * 100.0f);
        bool acknowledged = (acknowledge_button.read() == 0);

        if (percent < 40) {
            show_safe();
            printf("percent=%d level=SAFE ack=%d\n",
                   percent,
                   acknowledged);
        } else if (percent < 70) {
            show_warning();
            printf("percent=%d level=WARNING ack=%d\n",
                   percent,
                   acknowledged);
        } else {
            show_critical(acknowledged);
            printf("percent=%d level=CRITICAL ack=%d\n",
                   percent,
                   acknowledged);
        }

        ThisThread::sleep_for(500ms);
    }
}

Fill the table while you test. Use one row for each required state: safe, warning, critical with the button released, and critical with the button pressed. In Inputs used, write both the approximate potentiometer percent and the button state. In Serial evidence, copy the full printed line, such as percent=80 level=CRITICAL ack=1.
For the critical-released row, write blinking only after watching the status LED turn on and off repeatedly for at least two seconds.

The controller above is a starting point. Improve one part and test it again.

Choose one improvement:

- Change the warning or critical threshold and justify the new value.
- Add a slower or faster blink for the critical status LED.
- Add a serial line that prints mode=ACKNOWLEDGED when the button is pressed
in the critical state.
- Add a second severe-critical pattern for values above 90%.