Lolin ESP32-C3 PlatformIO Board

lolin_c3_pico.json

{
  "build": {
    "arduino": {
      "ldscript": "esp32c3_out.ld"
    },
    "core": "esp32",
    "extra_flags": [
      "-DARDUINO_LOLIN_C3_PICO",
      "-DARDUINO_USB_MODE=1",
      "-DARDUINO_USB_CDC_ON_BOOT=1"
    ],
    "f_cpu": "160000000L",
    "f_flash": "80000000L",
    "flash_mode": "qio",
    "hwids": [
      [
        "0X303A",
        "0x1001"
      ]
    ],
    "mcu": "esp32c3",
    "variant": "lolin_c3_pico"
  },
  "connectivity": [
    "wifi"
  ],
  "debug": {
    "openocd_target": "esp32c3.cfg"
  },
  "frameworks": [
    "arduino",
    "espidf"
  ],
  "name": "WEMOS LOLIN C3 Pico",
  "upload": {
    "flash_size": "4MB",
    "maximum_ram_size": 327680,
    "maximum_size": 4194304,
    "require_upload_port": true,
    "speed": 460800
  },
  "url": "https://www.wemos.cc/en/latest/c3/c3_pico.html",
  "vendor": "WEMOS"
}

pins_arduino.h

#ifndef Pins_Arduino_h
#define Pins_Arduino_h

#include <stdint.h>

#define EXTERNAL_NUM_INTERRUPTS 22
#define NUM_DIGITAL_PINS        22
#define NUM_ANALOG_INPUTS       6

#define analogInputToDigitalPin(p)  (((p)<NUM_ANALOG_INPUTS)?(analogChannelToDigitalPin(p)):-1)
#define digitalPinToInterrupt(p)    (((p)<NUM_DIGITAL_PINS)?(p):-1)
#define digitalPinHasPWM(p)         (p < EXTERNAL_NUM_INTERRUPTS)


static const uint8_t LED_BUILTIN = 7;
#define BUILTIN_LED  LED_BUILTIN // backward compatibility
#define LED_BUILTIN LED_BUILTIN
#define RGB_BUILTIN LED_BUILTIN
#define RGB_BRIGHTNESS 64


static const uint8_t TX = 21;
static const uint8_t RX = 20;

static const uint8_t SDA = 8;
static const uint8_t SCL = 10;

static const uint8_t SS    = 5;
static const uint8_t MOSI  = 4;
static const uint8_t MISO  = 3;
static const uint8_t SCK   = 2;

static const uint8_t A0 = 0;
static const uint8_t A1 = 1;
static const uint8_t A2 = 2;
static const uint8_t A3 = 3;
static const uint8_t A4 = 4;
static const uint8_t A5 = 5;

#endif /* Pins_Arduino_h */

I should probably create PRs for this, but I'm not 100% sure it's right. Use as your own risk.

~.platformio\platforms\espressif32\boards\lolin_c3_pico.json
~.platformio\packages\framework-arduinoespressif32\variants\lolin_c3_pico\pins_arduino.h