# Hello World

## Lab 1: Hello World - ทำความเข้าใจโปรเจกต์ & LED Blink

#### วัตถุประสงค์

* เข้าใจโครงสร้างโปรเจกต์ ModusToolBox (MTB)
* เข้าใจ flow ของ `main()` ใน Embedded system
* ควบคุม LED Blink ด้วย macro

#### จะได้เรียนรู้อะไร?

* **Project Structure**: proj\_cm33\_s, proj\_cm33\_ns, proj\_cm55
* **GPIO API**: Cy\_GPIO\_Set(), Cy\_GPIO\_Clr(), Cy\_GPIO\_Inv()
* **Delay Function**: Cy\_SysLib\_Delay()
* **Macro Definition**: สร้าง LED control macros

### Lab 1.1 : Hello World & LED Blink

#### ทำความเข้าใจโค้ด main.c

โค้ด `main()` ในตัวอย่าง Infineon จะมี pattern คงที่:

1. Initialize board และ peripherals
2. Enable global interrupt
3. Initialize UART สำหรับ debug (`printf`)
4. เข้า main loop ที่รันตลอดเวลา

```c
/* proj_cm33_ns/main.c - Hello World Example */

/*******************************************************************************
* File Name        : main.c
*
* Description      : This source file contains the main routine for non-secure
*                    application in the CM33 CPU
*
* Related Document : See README.md
*
********************************************************************************

/*******************************************************************************
* Header Files
*******************************************************************************/

#include "cybsp.h"
#include "retarget_io_init.h"

/*******************************************************************************
* Macros
*******************************************************************************/
#define BLINKY_LED_DELAY_MSEC       (1000U)

/* The timeout value in microseconds used to wait for CM55 core to be booted */
#define CM55_BOOT_WAIT_TIME_USEC    (10U)

/* App boot address for CM55 project */
#define CM55_APP_BOOT_ADDR          (CYMEM_CM33_0_m55_nvm_START + \
                                        CYBSP_MCUBOOT_HEADER_SIZE)

/*******************************************************************************
* Function Name: main
********************************************************************************
* Summary:
* This is the main function of the CM33 non-secure application. 
* 
* It initializes the device and board peripherals. It also initializes the 
* retarget-io middleware to be used with the debug UART port using which 
* "Hello World!" is printed on the debug UART. The LED pin is initialized with
* default configurations. The CM55 core is enabled and then the programs enters
* an infinite while loop which toggles the LED1 with a frequency of 1 Hz.
*
* Parameters:
*  none
*
* Return:
*  int
*
*******************************************************************************/
int main(void)
{
    cy_rslt_t result = CY_RSLT_SUCCESS;

    /* Initialize the device and board peripherals. */
    result = cybsp_init();

    /* Board initialization failed. Stop program execution. */
    if (CY_RSLT_SUCCESS != result)
    {
        handle_app_error();
    }

    /* Enable global interrupts */
    __enable_irq();

    /* Initialize retarget-io middleware */
    init_retarget_io();

    /* \x1b[2J\x1b[;H - ANSI ESC sequence for clear screen. */
    printf("\x1b[2J\x1b[;H");

    printf("****************** "
           "PSOC Edge MCU: Hello world "
           "****************** \r\n\n");

    printf("Hello World!\r\n\n");
    printf("For more projects, "
           "visit our code examples repositories:\r\n\n");

    printf("https://github.com/Infineon/"
           "Code-Examples-for-ModusToolbox-Software\r\n\n");

    /* Enable CM55. */
    /* CM55_APP_BOOT_ADDR must be updated if CM55 memory layout is changed.*/
    Cy_SysEnableCM55(MXCM55, CM55_APP_BOOT_ADDR, CM55_BOOT_WAIT_TIME_USEC);

    for(;;)
    {
        Cy_GPIO_Inv(CYBSP_USER_LED1_PORT, CYBSP_USER_LED1_PIN); // Toggle the LED1
        Cy_SysLib_Delay(BLINKY_LED_DELAY_MSEC); // Delay for 1 second
    }
}

/* [] END OF FILE */

```

#### แผนภาพการทำงาน

<div data-full-width="true"><figure><img src="/files/AQZ5XyKFJAqkkhbXLHUd" alt=""><figcaption></figcaption></figure></div>

***

#### LED Blink ด้วย Macro

กำหนด delay ของ LED ด้วย macro

```c
#define BLINKY_LED_DELAY_MSEC (1000U)
```

และใน main loop:

```c
for(;;)
    {
        Cy_GPIO_Inv(CYBSP_USER_LED1_PORT, CYBSP_USER_LED1_PIN); // Toggle the LED1
        Cy_SysLib_Delay(BLINKY_LED_DELAY_MSEC); // Delay for 1 second
    }
```

***

### ทดลองสร้าง LED API (Best Practice)

โดยการเพิ่ม macro เพื่อให้โค้ดอ่านง่ายขึ้น:

```c
#define LED_ON()     Cy_GPIO_Set(CYBSP_USER_LED1_PORT, CYBSP_USER_LED1_PIN)
#define LED_OFF()    Cy_GPIO_Clr(CYBSP_USER_LED1_PORT, CYBSP_USER_LED1_PIN)
#define LED_TOGGLE() Cy_GPIO_Inv(CYBSP_USER_LED1_PORT, CYBSP_USER_LED1_PIN)
```

แล้วเปลี่ยนใน loop เป็น:

```c
for(;;)
    {
        LED_TOGGLE(); // Toggle the LED1
        Cy_SysLib_Delay(BLINKY_LED_DELAY_MSEC); // Delay for 1 second
    }
```

***

**Build และ Flash**

```bash
make build -j8
make program
```

***

### Lab 1.2 : ทดลอง LED Blinking Patterns

```c
/* Pattern 1: Simple blink */
for(;;)
{
    LED_TOGGLE();
    Cy_SysLib_Delay(250);
}

/* Pattern 2: SOS pattern */
for(;;)
{
    /* S: ... */
    for (int i = 0; i < 3; i++) {
        LED_ON();  Cy_SysLib_Delay(100);
        LED_OFF(); Cy_SysLib_Delay(100);
    }
    Cy_SysLib_Delay(200);

    /* O: --- */
    for (int i = 0; i < 3; i++) {
        LED_ON();  Cy_SysLib_Delay(300);
        LED_OFF(); Cy_SysLib_Delay(100);
    }
    Cy_SysLib_Delay(200);

    /* S: ... */
    for (int i = 0; i < 3; i++) {
        LED_ON();  Cy_SysLib_Delay(100);
        LED_OFF(); Cy_SysLib_Delay(100);
    }

    Cy_SysLib_Delay(1000);  /* Pause between SOS */
}
```

**Build และ Flash**

```bash
make build -j8
make program
```

#### GPIO Functions (PDL) Summary

<table><thead><tr><th width="326.24786376953125">Function</th><th>Description</th></tr></thead><tbody><tr><td><code>Cy_GPIO_Set(port, pin)</code></td><td>Set pin HIGH</td></tr><tr><td><code>Cy_GPIO_Clr(port, pin)</code></td><td>Set pin LOW</td></tr><tr><td><code>Cy_GPIO_Inv(port, pin)</code></td><td>Toggle pin</td></tr><tr><td><code>Cy_GPIO_Read(port, pin)</code></td><td>Read pin (0 or 1)</td></tr><tr><td><code>Cy_GPIO_Write(port, pin, val)</code></td><td>Write 0 or 1</td></tr></tbody></table>

#### Hardware Info

| Component | Macro             | หมายเหตุ    |
| --------- | ----------------- | ----------- |
| User LED1 | `CYBSP_USER_LED1` | Active HIGH |
| User LED2 | `CYBSP_USER_LED2` | Active HIGH |

### ✍️ Exercise:&#x20;

1. **Double Blink :** สร้าง pattern ที่ LED กระพริบ 2 ครั้งเร็วๆ แล้วหยุดนาน

```bash
ON(100ms) - OFF(100ms) - ON(100ms) - OFF(500ms) - repeat
```

2. **Heartbeat :** สร้าง pattern เหมือนหัวใจเต้น (สั้น-ยาว-หยุด)

```bash
ON(50ms) - OFF(50ms) - ON(150ms) - OFF(500ms) - repeat
```

{% hint style="info" %}
**Hint**

**ตัวอย่างใช้ `for (;;)`**

```c
LED_ON();  Cy_SysLib_Delay(100);
LED_OFF(); Cy_SysLib_Delay(100);
```

{% endhint %}

***


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