【GD32L233C-START评测】3.USB键盘的实现

bzhou830

【GD32L233C-START评测】3.USB键盘的实现 [复制链接]

<i class="pstatus"> 本帖最后由 bzhou830 于 2022-2-27 21:59 编辑 </i>

[ 【GD32L233C-START评测】1.开箱测试点亮彩屏](https://bbs.eeworld.com.cn/thread-1193742-1-1.html " 【GD32L233C-START评测】1.开箱测试点亮彩屏")
[ 【GD32L233C-START评测】2.超级玛丽跑起来](https://bbs.eeworld.com.cn/thread-1193914-1-1.html " 【GD32L233C-START评测】2.超级玛丽跑起来")

## 1. 实现思路

在GD32L233C-start板子的官方例程中有一个USB CDC的案例，此外就没有任何USB相关的案例了。但是，从GD32L233R_EVAL_Demo_Suites里面找到了有USB键盘的案例，所以最简单的实现方式就是将这个Demo移植过来到GD32L233C-start板子上。由于GD32L233C-start上除了用于复位的按键之外只有一个可供输入的外部按键, 所以就用这个按键来实现键盘的输入。也就只是相当于实现了只有一个按键的键盘。

## 2. 设备描述符

设备描述符的配置在USBlyzer中可以看到如下所示：

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```
usb_desc_dev hid_dev_desc = {
  .header =
  {
  .bLength    = USB_DEV_DESC_LEN,
  .bDescriptorType= USB_DESCTYPE_DEV
  },
#ifdef LPM_ENABLED
  .bcdUSB      = 0x0201U,
#else
  .bcdUSB      = 0x0200U,
#endif /* LPM_ENABLED */
  .bDeviceClass    = 0x00U,
  .bDeviceSubClass   = 0x00U,
  .bDeviceProtocol   = 0x00U,
  .bMaxPacketSize0   = USBD_EP0_MAX_SIZE,
  .idVendor    = USBD_VID,//0x28E9U
  .idProduct     = USBD_PID,//0x0380U
  .bcdDevice     = 0x0100U,
  .iManufacturer   = STR_IDX_MFC,
  .iProduct    = STR_IDX_PRODUCT,
  .iSerialNumber   = STR_IDX_SERIAL,
  .bNumberConfigurations = USBD_CFG_MAX_NUM
};
```

## 3. 配置描述符

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```
  .config =
  {
  .header =
  {
    .bLength   = sizeof(usb_desc_config),
    .bDescriptorType = USB_DESCTYPE_CONFIG
  },
  .wTotalLength   = USB_HID_CONFIG_DESC_LEN,
  .bNumInterfaces   = 0x01U,
  .bConfigurationValue= 0x01U,
  .iConfiguration   = 0x00U,
  .bmAttributes   = 0xA0U,
  .bMaxPower    = 0x32U
  },
```

## 4. 接口描述符，端点描述符，HID描述符

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```
//接口描述符
  .header =
  {
    .bLength   = sizeof(usb_desc_itf),
    .bDescriptorType = USB_DESCTYPE_ITF
  },
  .bInterfaceNumber = 0x00U,
  .bAlternateSetting  = 0x00U,
  .bNumEndpoints  = 0x01U,
  .bInterfaceClass  = USB_HID_CLASS,
  .bInterfaceSubClass = USB_HID_SUBCLASS_BOOT_ITF,
  .bInterfaceProtocol = USB_HID_PROTOCOL_KEYBOARD,
  .iInterface   = 0x00U
```

```
//HID描述符
  .header =
  {
    .bLength   = sizeof(usb_desc_hid),
    .bDescriptorType = USB_DESCTYPE_HID
  },
  .bcdHID     = 0x0111U,
  .bCountryCode   = 0x00U,
  .bNumDescriptors  = 0x01U,
  .bDescriptorType  = USB_DESCTYPE_REPORT,
  .wDescriptorLength  = USB_HID_REPORT_DESC_LEN,
```

```
//端点描述符
  .header =
  {
    .bLength   = sizeof(usb_desc_ep),
    .bDescriptorType = USB_DESCTYPE_EP
  },
  .bEndpointAddress = HID_IN_EP,
  .bmAttributes   = USB_EP_ATTR_INT,
  .wMaxPacketSize   = HID_IN_PACKET,
  .bInterval    = 0x40U
```

## 5. HID报表描述符

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```
const uint8_t hid_report_desc[USB_HID_REPORT_DESC_LEN] = {
  0x05, 0x01,/* USAGE_PAGE (Generic Desktop) */
  0x09, 0x06,/* USAGE (Keyboard) */
  0xa1, 0x01,/* COLLECTION (Application) */

0x05, 0x07,/* USAGE_PAGE (Keyboard/Keypad) */
  0x19, 0xe0,/* USAGE_MINIMUM (Keyboard LeftControl) */
  0x29, 0xe7,/* USAGE_MAXIMUM (Keyboard Right GUI) */
  0x15, 0x00,/* LOGICAL_MINIMUM (0) */
  0x25, 0x01,/* LOGICAL_MAXIMUM (1) */
  0x95, 0x08,/* REPORT_COUNT (8) */
  0x75, 0x01,/* REPORT_SIZE (1) */
  0x81, 0x02,/* INPUT (Data,Var,Abs) */

0x95, 0x01,/* REPORT_COUNT (1) */
  0x75, 0x08,/* REPORT_SIZE (8) */
  0x81, 0x03,/* INPUT (Cnst,Var,Abs) */

0x95, 0x06,/* REPORT_COUNT (6) */
  0x75, 0x08,/* REPORT_SIZE (8) */
  0x15, 0x00,/* LOGICAL_MINIMUM (0) */
  0x26, 0xFF, 0x00,/* LOGICAL_MAXIMUM (255) */
  0x05, 0x07,/* USAGE_PAGE (Keyboard/Keypad) */
  0x19, 0x00,/* USAGE_MINIMUM (Reserved (no event indicated)) */
  0x29, 0x65,/* USAGE_MAXIMUM (Keyboard Application) */
  0x81, 0x00,/* INPUT (Data,Ary,Abs) */

0xc0   /* END_COLLECTION */
};
```

## 6. 按键处理
按键直接用循环扫描的方式进行：
```
static uint8_t key_state(void)
{
  if(SET == gpio_input_bit_get(GPIOA, GPIO_PIN_0)) 
        {
                return CHAR_B;
  }
  return 0U;
}

static void hid_key_data_send(usb_dev *udev)
{
  standard_hid_handler *hid = (standard_hid_handler *)udev->class_data[0];

if(hid->prev_transfer_complete) {
  switch(key_state()) {
  case CHAR_A:
    hid->data[2] = 0x04U;
    break;
  case CHAR_B:
    hid->data[2] = 0x05U;
    break;
  default:
    break;
  }

if(0U != hid->data[2]) {
    hid_report_send(udev, hid->data, HID_IN_PACKET);
  }
  }
}

```
至此，USB键盘就实现好了，运行起来在设备管理器里面可以找到一个VID是0x28E9U， PID是0x0380U的HID设备，按下按键即输入大写字母B。

soso

排版很舒服，赞

bzhou830

soso 发表于 2022-2-28 09:34 排版很舒服，赞

使用markdown排版的

serialworld

能否分享一下源文件？参考一下。

谢谢！

bzhou830

serialworld 发表于 2022-3-13 10:14 能否分享一下源文件？参考一下。谢谢！

源码公开在github上了。

https://github.com/bzhou830/GD32/tree/main/GD32L233C_START_Demo_Suites/Projects/08_USBD_keybord

serialworld

谢谢分享！！

【GD32L233C-START评测】3.USB键盘的实现 [复制链接]

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