【infineon】XMC1300シリーズのキットで簡単LED制御

void SysTick_Handler(void)
{
    static uint32_t ticks_uart = 0;
    static uint32_t ticks_led = 0;
    static uint8_t active_led = 1;
    static uint8_t message = 0;
    static const char *messages[] =
    {
        "Visit www.infineon.com/XMC\r\n",
        "Visit www.infineonforums.com\r\n\r\n"
    };

    uint8_t i;
    uint32_t adc_result;
    uint32_t ticks_led_event = TICKS_LED_EVENT;

    adc_result = VADC_G1->RES[0];

    // Check if result is valid
    if (adc_result & VADC_G_RES_VF_Msk)
    {
        adc_result &= VADC_G_RES_RESULT_Msk;
        adc_result = (adc_result >> 4);
        ticks_led_event += adc_result;
    }

    // Update LED status 
    ticks_led++;
    if (ticks_led >= ticks_led_event )
    {
        switch (active_led)
        {
          case 1:
            P0_0_toggle();
          break;

          case 2:
            P0_1_toggle();
          break;

          case 3:
            P0_6_toggle();
          break;

          case 4:
            P0_7_toggle();
          break;
 
          case 5:
            P0_8_toggle();
          break;

          case 6:
            P0_9_toggle();
          break;
 
          default:
          break;
        } 

        if (active_led == NUM_LEDS)
        {
            active_led = 1;
        }
        else
        {
            active_led++;
        }
        ticks_led = 0;
    }

    // Update UART message 
    ticks_uart++;
    if (ticks_uart == TICKS_UART_EVENT)
    {
        for(i = 0; i < strlen(messages[message]); i++)
        {
            USIC0_CH1->IN[0] = messages[message][i];
        }
        message ^= 1;
        ticks_uart = 0;
    }
}

/* ①点灯・消灯の間隔を決める初期値 */
#define TICKS_LED_EVENT (100)

/* ②関数内で使用する変数の宣言と初期化 */
uint32_t adc_result;
uint32_t ticks_led_event = TICKS_LED_EVENT;

/* ③AD変換結果をadc_resultに引き渡し */
adc_result = VADC_G1->RES[0];

/* ④点灯・消灯の間隔を更新 */
if (adc_result & VADC_G_RES_VF_Msk)
{
    adc_result &= VADC_G_RES_RESULT_Msk;
    adc_result = (adc_result >> 4);
    ticks_led_event += adc_result;
}

// Update LED status 
/* ①時間測定 */
ticks_led++;

/* ②制御間隔の確認 */
if (ticks_led >= ticks_led_event )
{
    /* ③LEDの選択 */
    switch (active_led)
    {
      case 1:
        P0_0_toggle(); /* ④LEDの点灯・消灯 */
      break;

    } 

    /* ⑤LEDの対象更新 */
    if (active_led == NUM_LEDS) /* NUM_LEDS = 6 */
    {
        active_led = 1;
    }
    else
    {
        active_led++;
    }

    /* ⑥インターバルの初期化 */
    ticks_led = 0;
}