feat(esp32s3): m5stack atom-s3u pindefs

as per https://docs.m5stack.com/en/core/AtomS3U

Author: mhaberler

variants/m5stack_atoms3u/pins_arduino.h

@@ -0,0 +1,53 @@
+#ifndef Pins_Arduino_h
+#define Pins_Arduino_h
+
+#include <stdint.h>
+#include "soc/soc_caps.h"
+
+#define USB_VID 0x303a
+#define USB_PID 0x1001
+
+// WS2812 RGB LED on pin 7
+#define PIN_RGB_LED 35
+// BUILTIN_LED can be used in new Arduino API digitalWrite() like in Blink.ino
+static const uint8_t LED_BUILTIN = SOC_GPIO_PIN_COUNT + PIN_RGB_LED;
+#define BUILTIN_LED LED_BUILTIN  // backward compatibility
+#define LED_BUILTIN LED_BUILTIN  // allow testing #ifdef LED_BUILTIN
+// RGB_BUILTIN and RGB_BRIGHTNESS can be used in new Arduino API rgbLedWrite()
+#define RGB_BUILTIN    LED_BUILTIN
+#define RGB_BRIGHTNESS 64
+
+// https://docs.m5stack.com/en/core/AtomS3U
+
+static const uint8_t IR_TX = 12;
+static const uint8_t BUTTON = 41;
+
+// grove port
+static const uint8_t SDA = 1;
+static const uint8_t SCL = 2;
+
+// grove port aliases
+static const uint8_t TCH1 = 1;
+static const uint8_t TCH2 = 2;
+static const uint8_t ACH0 = 1;
+static const uint8_t ACH1 = 2;
+
+// gpio
+static const uint8_t G14 = 14;
+static const uint8_t G17 = 17;
+static const uint8_t G40 = 40;
+static const uint8_t G42 = 42;
+
+// gpio aliases
+static const uint8_t A2CH3 = 14;
+static const uint8_t TCH14 = 14;
+static const uint8_t A2CH6 = 17;
+static const uint8_t CLK_OUT2 = 40;
+
+// i2s mic
+static const uint8_t MIC_CLK = 38;
+static const uint8_t MIC_DATA = 39;
+
+
+
+#endif /* Pins_Arduino_h */