# Frequently Asked Questions (FAQ)

## How to switch between LCD and HDMI display?

### Switch to LCD display

```bash
# 以 01studio 开发板为例
cd /boot
rm -f k.dtb
ln -s k230-canmv-01studio-lcd.dtb k.dtb
sync
reboot
```

### Switch to HDMI display

```bash
# 以 01studio 开发板为例
cd /boot
rm -f k.dtb
ln -s k230-canmv-01studio.dtb k.dtb
sync
reboot
```

### View current display configuration

```bash
# 查看 k.dtb 的软链接目标
ls -lh /boot/k.dtb

# 输出示例：
# lrwxrwxrwx 1 root root 23 Apr 17 10:10 /boot/k.dtb -> k230-canmv-01studio.dtb

# 判断规则：
# - 链接名称包含 "lcd" → 当前使用 LCD 显示
# - 链接名称不包含 "lcd" → 当前使用 HDMI 显示
```

---

## How to Connect to WiFi?

### Method 1: Configure via Environment Variables

```bash
fw_setenv wlanssid H3C_wjx
fw_setenv wlanpass 12345678
reboot
```

### Method 2: Use the sta.sh Script

```bash
sta.sh wlan0 H3C_wjx 12345678
```

---

## How to Switch Camera Channels (CSI0/CSI1/CSI2)?

K230 Linux SDK currently only supports single camera mode. To switch between different camera channels, please refer to:
[K230 Camera Channel Switching Instructions](https://mp.weixin.qq.com/s?src=11&timestamp=1779431414&ver=6735&signature=aw95mB4atDSBpCUyHH82Dm8JH8Xe2ci8cawX*fp0ywDAW*DnsJI6uj79EZqFaBDz91QFHTNAGh7jfHHu2*hV6gjaNuu9*Y8gr1kfOVl5rHPX-X727cGr5pCFYvJ*LY8Z&new=1&qbExtraParams=query%3Dk230%2520%2520linux%2520%25E6%2591%2584%25E5%2583%258F%25E5%25A4%25B4%25E5%2588%2587%25E6%258D%25A2%26source%3D30010541%26docId%3D90000105_oIWsFt14I7M-vOy9BLRJyLv2w7Vw_2247484781_1)

---

## How to Enable the GDB Debugger?

Enable via MenuConfig:

```bash
make menuconfig
# 路径：Target packages → Debugging, profiling and benchmark → gdb → full debugger
```

Or directly modify the configuration file:

```bash
BR2_PACKAGE_GDB=y
BR2_PACKAGE_GDB_DEBUGGER=y
```

---

## How to Quickly Update the Kernel and Device Tree?

Directly replace the relevant files in the `/boot` directory:

```bash
ls -lh /boot/
# 输出说明：
# Image                          # 内核镜像
# fw_jump_add_uboot_head.bin     # U-Boot 启动镜像
# k.dtb                          # 设备树符号链接
# k230-canmv-*.dtb               # 具体的设备树文件
# nuttx-*.bin                    # NuttX 固件
```

---

## How to Verify DDR Memory Stability?

Run the following commands to generate DDR test images:

```bash
make ddr_test_img_128    # 128MB DDR 测试镜像
make ddr_test_img_512    # 512MB DDR 测试镜像
make ddr_test_img_1024   # 1024MB DDR 测试镜像
make ddr_test_img_2048   # 2048MB DDR 测试镜像
```

The generated images will automatically run the DDR stability test program (running continuously). During the test, the serial port will continuously output relevant information; if the test fails, the serial port will print error messages.

---

## What Hardware Does the SDK Currently Support?

| Development Board | CPU   | Configuration File                   | Notes  |
| ------------ | ----- | ------------------------------------ | ------ |
| Banana Pi    | k230d | BPI-CanMV-K230D-Zero_defconfig       | 64-bit |
| Banana Pi    | k230d | BPI-CanMV-K230D-Zero_ilp32_defconfig | 32-bit |
| k230d_canmv  | k230d | k230d_canmv_defconfig                | 64-bit |
| 01studio     | k230  | k230_canmv_01studio_defconfig        |        |
| Dongshan Pi  | k230  | k230_canmv_dongshanpi_defconfig      |        |
| JLCPCB       | k230  | k230_canmv_lckfb_defconfig           |        |
| ChuangLebo   | k230  | k230_canmv_v3_defconfig              |        |
| canmv1.0/1.1 | k230  | k230_canmv_defconfig                 |        |
| evb          | k230  | k230_evb_defconfig                   | lpddr3 |

---

## What LCD Screens Does the Linux SDK Support?

| Driver Chip | Resolution | Applicable Development Boards     |
| -------- | --------- | -------------------------- |
| ST7701   | 480×640   | 01studio                   |
| ST7701   | 480×800   | JLCPCB / 01studio / ChuangLebo |
| ILI9806  | 480×800   | Dongshan Pi                |
| HX8399   | 1080×1920 | EVB                        |

---

## What Camera Modules Does the K230 Linux SDK Support?

| Model  | Pixels | Notes |
| ------ | ----- | ---- |
| GC2093 | 2MP    |      |
| OV5647 | 5MP    |      |
| IMX335 | 5MP    |      |