Update README

README.md

@@ -2,26 +2,121 @@
 
 ESPHome component to control Daikin indoor mini-split units with s21 ports.
 
-## Example
+Many thanks to the work by [revk][1] on the fantastic [Faikin][2] project, which
+was the primary inspiration and guide for building this ESPHome component.
+
+## Features
+
+- Setpoint temperature.
+- Climate modes COOL, HEAT, DRY, FAN, and HEAT_COOL.
+- Fan modes auto and 1-5.
+- Swing modes horizontal, vertical, and both.
+
+Sensors:
+* Inside temperature (usually measured at indoor air handler return)
+* Outside temperature (outside exchanger)
+* Coil temperature (indoor air handler's coil)
+* Fan speed
+
+## Limitations
+
+* This code has only been tested on ESP32 pico.
+* Does not detect nor support powerful, econo, quiet modes.
+* Does not support comfort or presence detection features on some models.
+* Does not interact with the indoor units schedules (do that with HA instead).
+
+## Hardware
+
+### S21 Port
+
+**NOTE:** The Daikin S21 port provides >5V, so if you intend to power your
+board on this pin, be sure to test its output and regulate voltage accordingly.
+
+On my Daikin units, the S21 port has the following pins:
+
+* 1 - Unused
+* 2 - TX (5V)
+* 3 - RX (5V)
+* 4 - VCC (>5V!!)
+* 5 - GND
+
+The S21 plug is JST `EHR-5` and related header `B5B-EH-A(LF)(SN)`, though the
+plug pins are at standard pin header widths.
+
+### PCB
+
+I've been using the board designed by [revk][1] available [here][3]. Note that
+revk's design includes a FET that inverts the logic levels on the ESP's RX pin,
+which required using two separate UART devices to get around an ESPHome limit
+on having pins inverted differently.
+
+[1]: https://github.com/revk
+[2]: https://github.com/revk/ESP32-Faikin
+[3]: https://github.com/revk/ESP32-Faikin/tree/main/PCB/Faikin
+
+## Configuration Example
 
 ```yaml
 logger:
   baud_rate: 0  # Disable UART logger if using UART0 (pins 1,3)
 
+external_components:
+  - source: github://joshbenner/esphome-daikin-s21@main
+
 uart:
-  tx_pin: GPIO1
-  rx_pin: GPIO3
-  baud_rate: 2400
+  - id: s21_uart
+    tx_pin: GPIO1
+    rx_pin: GPIO3
+    baud_rate: 2400
+    data_bits: 8
+    parity: EVEN
+    stop_bits: 2
+
+# The base UART communication hub.
+daikin_s21:
+  tx_uart: s21_uart
+  rx_uart: s21_uart
 
 climate:
+  - name: My Daikin
+    platform: daikin_s21
+    visual:
+      temperature_step: 1.0
+
+# Optional additional sensors.
+sensor:
   - platform: daikin_s21
-    name: My Daikin Mini-Split
+    inside_temperature:
+      name: My Daikin Inside Temperature
+    outside_temperature:
+      name: My Daikin Outside Temperature
+    coil_temperature:
+      name: My Daikin Coil Temperature
+    fan_speed:
+      name: My Daikin Fan Speed
 ```
 
-## Daikin S21 UART Notes
+Here is an example of how daikin_s21 can be used with one inverted UART pin:
 
-* Baud rate: 2400
-* Data bits: 8
-* Parity: Even
-* Stop bits: 2
-* Flow Ctrl: No
+```yaml
+uart:
+  - id: s21_tx
+    tx_pin: 26
+    baud_rate: 2400
+    data_bits: 8
+    parity: EVEN
+    stop_bits: 2
+
+  - id: s21_rx
+    rx_pin:
+      number: 27
+      inverted: true
+    baud_rate: 2400
+    data_bits: 8
+    parity: EVEN
+    stop_bits: 2
+
+daikin_s21:
+  tx_uart: s21_tx
+  rx_uart: s21_rx
+```