Support for AM2320 temperature and humidity sensor (#554)

Support for AM2320 temperature and humidity sensor

Co-authored-by: Mikkonen Teemu <teemu.mikkonen@iki.fi>

esphome/components/am2320/am2320.cpp

@@ -0,0 +1,107 @@
+// Implementation based on:
+//  - ESPEasy: https://github.com/letscontrolit/ESPEasy/blob/mega/src/_P034_DHT12.ino
+//  - DHT12_sensor_library: https://github.com/xreef/DHT12_sensor_library/blob/master/DHT12.cpp
+//  - Arduino - AM2320: https://github.com/EngDial/AM2320/blob/master/src/AM2320.cpp
+
+#include "am2320.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace am2320 {
+
+static const char *TAG = "am2320";
+
+// ---=== Calc CRC16 ===---
+uint16_t crc_16(uint8_t *ptr, uint8_t length) {
+  uint16_t crc = 0xFFFF;
+  uint8_t i;
+  //------------------------------
+  while (length--) {
+    crc ^= *ptr++;
+    for (i = 0; i < 8; i++)
+      if ((crc & 0x01) != 0) {
+        crc >>= 1;
+        crc ^= 0xA001;
+      } else
+        crc >>= 1;
+  }
+  return crc;
+}
+
+void AM2320Component::update() {
+  uint8_t data[8];
+  data[0] = 0;
+  data[1] = 4;
+  if (!this->read_data_(data)) {
+    this->status_set_warning();
+    return;
+  }
+
+  float temperature = (((data[4] & 0x7F) << 8) + data[5]) / 10.0;
+  temperature = (data[4] & 0x80) ? -temperature : temperature;
+  float humidity = ((data[2] << 8) + data[3]) / 10.0;
+
+  ESP_LOGD(TAG, "Got temperature=%.1f°C humidity=%.1f%%", temperature, humidity);
+  if (this->temperature_sensor_ != nullptr)
+    this->temperature_sensor_->publish_state(temperature);
+  if (this->humidity_sensor_ != nullptr)
+    this->humidity_sensor_->publish_state(humidity);
+  this->status_clear_warning();
+}
+void AM2320Component::setup() {
+  ESP_LOGCONFIG(TAG, "Setting up AM2320...");
+  uint8_t data[8];
+  data[0] = 0;
+  data[1] = 4;
+  if (!this->read_data_(data)) {
+    this->mark_failed();
+    return;
+  }
+}
+void AM2320Component::dump_config() {
+  ESP_LOGD(TAG, "AM2320:");
+  LOG_I2C_DEVICE(this);
+  if (this->is_failed()) {
+    ESP_LOGE(TAG, "Communication with AM2320 failed!");
+  }
+  LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
+  LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
+}
+float AM2320Component::get_setup_priority() const { return setup_priority::DATA; }
+
+bool AM2320Component::read_bytes_(uint8_t a_register, uint8_t *data, uint8_t len, uint32_t conversion) {
+  if (!this->write_bytes(a_register, data, 2)) {
+    ESP_LOGW(TAG, "Writing bytes for AM2320 failed!");
+    return false;
+  }
+
+  if (conversion > 0)
+    delay(conversion);
+  return this->parent_->raw_receive(this->address_, data, len);
+}
+
+bool AM2320Component::read_data_(uint8_t *data) {
+  // Wake up
+  this->write_bytes(0, data, 0);
+
+  // Write instruction 3, 2 bytes, get 8 bytes back (2 preamble, 2 bytes temperature, 2 bytes humidity, 2 bytes CRC)
+  if (!this->read_bytes_(3, data, 8, 2)) {
+    ESP_LOGW(TAG, "Updating AM2320 failed!");
+    return false;
+  }
+
+  uint16_t checksum;
+
+  checksum = data[7] << 8;
+  checksum += data[6];
+
+  if (crc_16(data, 6) != checksum) {
+    ESP_LOGW(TAG, "AM2320 Checksum invalid!");
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace am2320
+}  // namespace esphome