Add TWI (I2C) init for ESP32

firmware/esp32/include/i2c.hpp

@@ -0,0 +1,6 @@
+#ifndef I2C_HPP
+#define I2C_HPP
+
+void i2cTask(void *pvParameters);
+
+#endif

firmware/esp32/main/i2c.cpp

@@ -0,0 +1,58 @@
+#include <stdint.h>
+#include "driver/i2c_master.h"
+#include "esp_log.h"
+
+// ESP32-C3 Super Mini, change this ports for other versions
+#define I2C_MASTER_SCL_IO 9
+#define I2C_MASTER_SDA_IO 8
+
+// TODO: put this in a config.hpp
+// Change based on how many vases max to manage [1 to ~100]
+// larger number will require larger array
+// see limitation on AVR addresses for TWI
+#define SLAVES_NUMBER 32
+
+i2c_master_bus_handle_t bus_handle;
+i2c_master_dev_handle_t slave_handles[SLAVES_NUMBER];
+uint8_t slave_count = 0;
+
+static void register_slave(int addr) {
+    i2c_device_config_t slave_dev_cfg = {
+        .dev_addr_length = I2C_ADDR_BIT_LEN_7,
+        .device_address = addr,
+        .scl_speed_hz = 100000, // 100kHz or 400kHz
+    };
+
+    ESP_ERROR_CHECK(i2c_master_bus_add_device(bus_handle, &slave_dev_cfg, &slave_handles[slave_count]));
+    slave_count++;
+}
+
+static void i2c_init(void) {
+    i2c_master_bus_config_t i2c_mst_config = {
+    .clk_source = I2C_CLK_SRC_DEFAULT,
+    .i2c_port = -1,
+    .scl_io_num = I2C_MASTER_SCL_IO,
+    .sda_io_num = I2C_MASTER_SDA_IO,
+    .glitch_ignore_cnt = 7,
+    .flags.enable_internal_pullup = true,
+};
+
+    ESP_ERROR_CHECK(i2c_new_master_bus(&i2c_mst_config, &bus_handle));
+
+    // Add all vases adresses here:
+    register_slave(0x30);
+}
+
+void i2c_read() {}
+void i2c_write() {}
+
+void i2cTask(void *pvParameters) {
+    i2c_init();
+
+    for(;;) {
+        // Logic:
+        // avr will talk only if spoken by esp32
+        // so keep reading from mqtt (mqtt.cpp):
+        // if get told from mqtt to read/write from/to avr -> i2c_write() -> loop i2c_read() until get response -> if needed mqtt_respond()
+    }
+}