/*
 * CH224K USB PD Voltage Selector
 * MCU: CH32V003F4P6 (WCH RISC-V)
 *
 * Cycles through 5V → 9V → 12V → 15V → 20V on each button press.
 * Drives CH224K CFG1/CFG2/CFG3 pins to set the requested PD voltage
 * and lights the corresponding indicator LED.
 *
 * Pin mapping (from schematic):
 *   PD2 → CFG1  (CH224K pin 9)
 *   PD3 → CFG2  (CH224K pin 2)
 *   PD4 → CFG3  (CH224K pin 3)
 *   PC0 → LED1  (5V indicator)
 *   PC1 → LED3  (9V indicator)
 *   PC2 → LED4  (12V indicator)
 *   PC3 → LED5  (15V indicator)
 *   PC4 → LED6  (20V indicator)
 *   PC6 → SW3   (push button, 10k pull-down via R2, press = HIGH)
 *   LED2 is hardware-driven by CH224K PG (power-good, open-drain active-low)
 *
 * LED1/3/4/5/6 are ACTIVE-HIGH: anodes on PC0-PC4, cathodes share
 * R12 (1k) to GND. Pin HIGH = LED on.
 *
 * CH224K level-configuration truth table (datasheet §5.2.2):
 *   CFG1  CFG2  CFG3  │ Voltage
 *   ─────────────────────────────
 *     1     -     -   │   5 V
 *     0     0     0   │   9 V
 *     0     0     1   │  12 V
 *     0     1     1   │  15 V
 *     0     1     0   │  20 V
 */

#include "debug.h"

/* ---------- CFG pins (Port D) ---------- */
#define CFG1_PIN        GPIO_Pin_2      /* PD2 */
#define CFG2_PIN        GPIO_Pin_3      /* PD3 */
#define CFG3_PIN        GPIO_Pin_4      /* PD4 */
#define CFG_ALL         (CFG1_PIN | CFG2_PIN | CFG3_PIN)

/* ---------- LED pins (Port C, active-HIGH) ---------- */
#define LED_5V          GPIO_Pin_0      /* PC0 – LED1 */
#define LED_9V          GPIO_Pin_1      /* PC1 – LED3 */
#define LED_12V         GPIO_Pin_2      /* PC2 – LED4 */
#define LED_15V         GPIO_Pin_3      /* PC3 – LED5 */
#define LED_20V         GPIO_Pin_4      /* PC4 – LED6 */
#define LED_ALL         (LED_5V | LED_9V | LED_12V | LED_15V | LED_20V)

/* ---------- Button pin (Port C) ---------- */
#define BTN_PIN         GPIO_Pin_6      /* PC6 – SW3 */

/* Lookup tables indexed by mode (0-4 → 5V,9V,12V,15V,20V) */
static const uint8_t cfg1_table[] = { 1, 0, 0, 0, 0 };
static const uint8_t cfg2_table[] = { 0, 0, 0, 1, 1 };
static const uint8_t cfg3_table[] = { 0, 0, 1, 1, 0 };
static const uint16_t led_table[] = { LED_5V, LED_9V, LED_12V, LED_15V, LED_20V };

volatile uint8_t modeIndex = 0;     /* 0=5V … 4=20V */
static uint8_t btn_prev   = 0;

/* ---------------------------------------------------------- */
void GPIO_Config(void)
{
    GPIO_InitTypeDef gpio = {0};

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD, ENABLE);

    /* PC0-PC4: push-pull outputs (LEDs) */
    gpio.GPIO_Pin   = LED_ALL;
    gpio.GPIO_Mode  = GPIO_Mode_Out_PP;
    gpio.GPIO_Speed = GPIO_Speed_30MHz;
    GPIO_Init(GPIOC, &gpio);

    /* PC6: floating input (button – external 10k pull-down via R2) */
    gpio.GPIO_Pin  = BTN_PIN;
    gpio.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOC, &gpio);

    /* PD2-PD4: push-pull outputs (CH224K CFG1/CFG2/CFG3) */
    gpio.GPIO_Pin   = CFG_ALL;
    gpio.GPIO_Mode  = GPIO_Mode_Out_PP;
    gpio.GPIO_Speed = GPIO_Speed_30MHz;
    GPIO_Init(GPIOD, &gpio);

    /* LEDs off at start (active-high: LOW = off) */
    GPIO_ResetBits(GPIOC, LED_ALL);
}

/* Drive CFG1/CFG2/CFG3 to the CH224K */
static void setCFG(uint8_t c1, uint8_t c2, uint8_t c3)
{
    if (c1) GPIO_SetBits(GPIOD, CFG1_PIN);
    else    GPIO_ResetBits(GPIOD, CFG1_PIN);

    if (c2) GPIO_SetBits(GPIOD, CFG2_PIN);
    else    GPIO_ResetBits(GPIOD, CFG2_PIN);

    if (c3) GPIO_SetBits(GPIOD, CFG3_PIN);
    else    GPIO_ResetBits(GPIOD, CFG3_PIN);
}

/* Apply current mode: update CFG pins and light matching LED */
void applyMode(void)
{
    /* All LEDs off */
    GPIO_ResetBits(GPIOC, LED_ALL);

    /* Set CH224K configuration */
    setCFG(cfg1_table[modeIndex],
           cfg2_table[modeIndex],
           cfg3_table[modeIndex]);

    /* Light the corresponding LED (active-high: HIGH = on) */
    GPIO_SetBits(GPIOC, led_table[modeIndex]);
}

/* Poll button with debounce, advance mode on rising edge */
void readButton(void)
{
    uint8_t btn_now = GPIO_ReadInputDataBit(GPIOC, BTN_PIN);

    if (btn_now == Bit_SET && btn_prev == Bit_RESET)
    {
        Delay_Ms(20);                           /* debounce */

        if (GPIO_ReadInputDataBit(GPIOC, BTN_PIN) == Bit_SET)
        {
            modeIndex++;
            if (modeIndex >= 5)
                modeIndex = 0;

            applyMode();
        }
    }

    btn_prev = btn_now;
}

/* ---------------------------------------------------------- */
int main(void)
{
    SystemCoreClockUpdate();
    Delay_Init();
    GPIO_Config();

    /* Boot into 5V – the safest default */
    modeIndex = 0;
    applyMode();

    while (1)
    {
        readButton();
    }
}