RP2040 SSM - Raspberry Pi Pico USB Custom HID 테스트

Raspberry Pi Pico USB Custom HID 를 테스트 해 보자

 

TinyUSB의 기본 HID예제코드에서 데이터 수신시 실행되는 콜백함수(set_report_callback) 를 수정 해서 간단히 LED 제어를 해 볼 수 있다.

#include "Adafruit_TinyUSB.h"

int led_flag = 0;
// HID report descriptor using TinyUSB's template
// Generic In Out with 64 bytes report (max)
uint8_t const desc_hid_report[] =
{
  TUD_HID_REPORT_DESC_GENERIC_INOUT(64)
};

// USB HID object.
Adafruit_USBD_HID usb_hid(desc_hid_report, sizeof(desc_hid_report), HID_ITF_PROTOCOL_NONE, 2, true);

// the setup function runs once when you press reset or power the board
void setup()
{
  pinMode(LED_BUILTIN, OUTPUT);
#if defined(ARDUINO_ARCH_MBED) && defined(ARDUINO_ARCH_RP2040)
  // Manual begin() is required on core without built-in support for TinyUSB such as mbed rp2040
  TinyUSB_Device_Init(0);
#endif

  // Notes: following commented-out functions has no affect on ESP32
  // usb_hid.enableOutEndpoint(true);
  // usb_hid.setPollInterval(2);
  // usb_hid.setReportDescriptor(desc_hid_report, sizeof(desc_hid_report));
  // usb_hid.setStringDescriptor("TinyUSB HID Generic");

  usb_hid.setReportCallback(get_report_callback, set_report_callback);
  usb_hid.begin();

  Serial.begin(115200);

  // wait until device mounted
  while( !TinyUSBDevice.mounted() ) delay(1);

  Serial.println("Adafruit TinyUSB HID Generic In Out example");
}

void loop()
{
  // nothing to do
}

// Invoked when received GET_REPORT control request
uint16_t get_report_callback (uint8_t report_id, hid_report_type_t report_type, uint8_t* buffer, uint16_t reqlen)
{
  // not used in this example
  (void) report_id;
  (void) report_type;
  (void) buffer;
  (void) reqlen;

  return 0;
}

// Invoked when received SET_REPORT control request or
// received data on OUT endpoint ( Report ID = 0, Type = 0 )
void set_report_callback(uint8_t report_id, hid_report_type_t report_type, uint8_t const* buffer, uint16_t bufsize)
{
  // This example doesn't use multiple report and report ID
  (void) report_id;
  (void) report_type;


  Serial.println("set_report_callback");
  Serial.printf("[%x] %x, %x, %x\r\n", report_id, buffer[0], buffer[1], buffer[2]);

  if(buffer[2])digitalWrite(LED_BUILTIN, 1);
  else digitalWrite(LED_BUILTIN, 0);

  // echo back anything we received from host
  usb_hid.sendReport(0, buffer, bufsize);
}

 

 

 

PC소프트웨어는 기존 HID  테스트 프로그램을 수정해서 테스트 했다.

 

 

기존의 MCU에서 HID를 구현 하려면 고려해야 할 사항이 많은데 RP2040에서 TinyUSB를 이용하니 상당히 편리 한것 같다.

다만 라이브러리를 사용하면 세세한 부분까지 제어하기 어려운 부분이 있을 수 있다.

// HID Generic Input & Output
// - 1st parameter is report size (mandatory)
// - 2nd parameter is report id HID_REPORT_ID(n) (optional)
#define TUD_HID_REPORT_DESC_GENERIC_INOUT(report_size, ...) \
    HID_USAGE_PAGE_N ( HID_USAGE_PAGE_VENDOR, 2   ),\
    HID_USAGE        ( 0x01                       ),\
    HID_COLLECTION   ( HID_COLLECTION_APPLICATION ),\
      /* Report ID if any */\
      __VA_ARGS__ \
      /* Input */ \
      HID_USAGE       ( 0x02                                   ),\
      HID_LOGICAL_MIN ( 0x00                                   ),\
      HID_LOGICAL_MAX ( 0xff                                   ),\
      HID_REPORT_SIZE ( 8                                      ),\
      HID_REPORT_COUNT( report_size                            ),\
      HID_INPUT       ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE ),\
      /* Output */ \
      HID_USAGE       ( 0x03                                    ),\
      HID_LOGICAL_MIN ( 0x00                                    ),\
      HID_LOGICAL_MAX ( 0xff                                    ),\
      HID_REPORT_SIZE ( 8                                       ),\
      HID_REPORT_COUNT( report_size                             ),\
      HID_OUTPUT      ( HID_DATA | HID_VARIABLE | HID_ABSOLUTE  ),\
    HID_COLLECTION_END \