77:T45a,#include #include volatile uint8_t adc_value = 0; volatile uint16_t duty_cycle = 0; void adc_init(void) { ADMUX |= (1 << REFS0); ADCSRA |= (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0); ADCSRA |= (1 << ADEN); ADCSRA |= (1 << ADSC); } uint16_t adc_read(uint8_t channel) { ADMUX = (ADMUX & 0xF0) | (channel & 0x0F); ADCSRA |= (1 << ADSC); while (ADCSRA & (1 << ADSC)); return ADC; } void pwm_init(void) { DDRB |= (1 << PB1); TCCR1A |= (1 << WGM10); TCCR1A |= (1 << COM1A1); TCCR1B |= (1 << CS11); } void pi_controller(void) { static int16_t integral = 0; int16_t error = 512 - (int16_t)adc_value; integral += error; if (integral > 1000) integral = 1000; if (integral < -1000) integral = -1000; int16_t output = (error * 2) + (integral >> 2); if (output > 255) output = 255; if (output < 0) output = 0; OCR1AL = (uint8_t)output; } int main(void) { adc_init(); pwm_init(); while (1) { adc_value = (uint8_t)(adc_read(0) >> 2); pi_controller(); _delay_ms(10); } } 4c:["$","div","pre-0",{"className":"overflow-x-auto w-full my-6 bg-surface p-4 rounded-xl","children":["$","pre",null,{"className":"text-xs sm:text-sm my-0! bg-transparent! p-0!","children":["$","code","code-0",{"className":"language-c","children":"$77"}]}]}] 4d:["$","p","p-17",{"className":"mb-8 leading-relaxed","children":["[[SIM:CPlayground]]\n",["$","strong","strong-0",{"className":"text-brand-500 font-black","children":"Simulation -- EmbeddedCPlayground"}],"\n| Field | Detail |\n|---|---|\n| Render type | 2D Code Editor + Virtual MCU |\n| ME domain | Embedded Programming |\n| User inputs | 1. Write/Edit C code in the editor","
","2. Press \"Compile & Run\" to see execution","
","3. View register values in real-time |\n| Primary visual | Split view: code editor on left, virtual microcontroller with animated register values and pin states on right. |\n| Secondary output | Serial monitor output and oscilloscope view of PWM pin. |\n| \"Aha\" moment | Forgetting \"volatile\" on a shared variable causes the virtual compiler to optimize away a loop, demonstrating the bug visually. |"]}] 4e:["$","h2","h2-3",{"className":"text-3xl font-black mt-16 mb-6","children":"Worked Examples"}] 4f:["$","h3","h3-5",{"className":"text-2xl font-bold mt-12 mb-6 text-foreground/90","children":"Example 1 -- Foundational (Blink LED with Timer)"}] 50:["$","div","pre-1",{"className":"overflow-x-auto w-full my-6 bg-surface p-4 rounded-xl","children":["$","pre",null,{"className":"text-xs sm:text-sm my-0! bg-transparent! p-0!","children":["$","code","code-0",{"className":"language-c","children":"#define F_CPU 16000000UL\n#include \n#include \n\nint main(void) {\n DDRB |= (1 << PB5);\n while (1) {\n PORTB |= (1 << PB5);\n _delay_ms(500);\n PORTB &= ~(1 << PB5);\n _delay_ms(500);\n }\n}\n"}]}]}] 51:["$","h3","h3-6",{"className":"text-2xl font-bold mt-12 mb-6 text-foreground/90","children":"Example 2 -- Industry-Grade (Debounced Button Interrupt)"}] 52:["$","div","pre-2",{"className":"overflow-x-auto w-full my-6 bg-surface p-4 rounded-xl","children":["$","pre",null,{"className":"text-xs sm:text-sm my-0! bg-transparent! p-0!","children":["$","code","code-0",{"className":"language-c","children":"#include \n#include \n\nvolatile uint8_t button_pressed = 0;\n\nISR(INT0_vect) {\n static uint16_t last_time = 0;\n uint16_t now = TCNT1;\n if ((now - last_time) > 5000) {\n button_pressed = 1;\n }\n last_time = now;\n}\n\nint main(void) {\n DDRB |= (1 << PB5);\n PORTD |= (1 << PD2);\n EICRA |= (1 << ISC01);\n EIMSK |= (1 << INT0);\n TCCR1B |= (1 << CS11);\n sei();\n while (1) {\n if (button_pressed) {\n PORTB ^= (1 << PB5);\n button_pressed = 0;\n }\n }\n}\n"}]}]}] 53:["$","h2","h2-4",{"className":"text-3xl font-black mt-16 mb-6","children":"Common Misconceptions & Failure Modes"}] 54:["