// Example of STM32 GPIO configuration
void GPIO_Init(void) {
    // Enable GPIOA clock
    RCC->AHB2ENR |= RCC_AHB2ENR_GPIOAEN;
    
    // Configure PA5 as output
    GPIOA->MODER &= ~GPIO_MODER_MODE5_Msk;
    GPIOA->MODER |= GPIO_MODER_MODE5_0;  // Output mode
    
    // Configure speed and type
    GPIOA->OSPEEDR |= GPIO_OSPEEDR_OSPEED5_0;  // Medium speed
    GPIOA->OTYPER &= ~GPIO_OTYPER_OT5;  // Push-pull
}

// Example of PID control implementation on STM32
typedef struct {
    float Kp, Ki, Kd;
    float setpoint;
    float error_sum;
    float last_error;
    float output_limit;
} PID_Controller;
 
float PID_Calculate(PID_Controller* pid, float measured_value) {
    float error = pid->setpoint - measured_value;
    
    // Proportional term
    float p_term = pid->Kp * error;
    
    // Integral term
    pid->error_sum += error;
    float i_term = pid->Ki * pid->error_sum;
    
    // Derivative term
    float d_term = pid->Kd * (error - pid->last_error);
    pid->last_error = error;
    
    // Calculate output
    float output = p_term + i_term + d_term;
    
    // Limit output
    if(output > pid->output_limit) output = pid->output_limit;
    if(output < -pid->output_limit) output = -pid->output_limit;
    
    return output;
}

// Basic STM32 project structure
#include "stm32f4xx_hal.h"
 
// Global variables
UART_HandleTypeDef huart2;
 
// Function prototypes
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
 
int main(void) {
    // Reset of all peripherals, initializes the Flash interface and the Systick
    HAL_Init();
    
    // Configure the system clock
    SystemClock_Config();
    
    // Initialize all configured peripherals
    MX_GPIO_Init();
    MX_USART2_UART_Init();
    
    // Main loop
    while (1) {
        // Your application code here
        HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
        HAL_Delay(500);
    }
}

// Simple LED blink example
void LED_Blink_Init(void) {
    // Enable GPIOC clock
    __HAL_RCC_GPIOC_CLK_ENABLE();
    
    // Configure PC13 as output
    GPIO_InitTypeDef GPIO_InitStruct = {0};
    GPIO_InitStruct.Pin = GPIO_PIN_13;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
}
 
void LED_Blink_Process(void) {
    HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
    HAL_Delay(500);
}

// Example of entering low-power mode
void Enter_Sleep_Mode(void) {
    // Configure wake-up source
    HAL_PWR_EnableWakeUpPin(PWR_WAKEUP_PIN1);
    
    // Enter sleep mode
    HAL_PWR_EnterSLEEPMode(PWR_LOWPOWERREGULATOR_ON, PWR_SLEEPENTRY_WFI);
    
    // Code continues here after wake-up
}

// Example of DMA configuration for ADC
void DMA_Init(void) {
    // Enable DMA clock
    __HAL_RCC_DMA1_CLK_ENABLE();
    
    // Configure DMA
    hdma_adc1.Instance = DMA1_Stream0;
    hdma_adc1.Init.Channel = DMA_CHANNEL_0;
    hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
    hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
    hdma_adc1.Init.Mode = DMA_CIRCULAR;
    hdma_adc1.Init.Priority = DMA_PRIORITY_HIGH;
    hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    
    HAL_DMA_Init(&hdma_adc1);
}