Add ESP32 d1 mini how to setup

README.md

@@ -68,6 +68,8 @@ Refer to [Sw_getting_started.md](docs/Sw_getting_started.md)
 
 Some details about some specific implementations:
 - ESP8266 + MAX485 +  EPEVER Solar Tracer [HOW TO](docs/Esp8266_max485_epever_rj45.md)
+- ESP32 D1 MINI + MAX485 +  EPEVER Solar Tracer [HOW TO](docs/Esp32_d1_mini_max485_epever_rj45.md)
+
 
 ## Reference
 

docs/Esp32_d1_mini_max485_epever_rj45.md

@@ -0,0 +1,52 @@
+# Connect  ESP32 D1 MINI  to EPEVER A/B Series ( + MAX485) 
+
+Here the material involved:
+* [ESP32 D1 MINI](https://www.aliexpress.com/premium/esp32-d1-mini.html?d=y&origin=y&catId=0&initiative_id=SB_20210919083440&SearchText=esp32%20d1%20mini)
+* [EPSolar/EPEver Tracer A/B-Series](https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20170114172728&SearchText=tracer+mppt+rs485)
+* [MAX 485 UART Module](https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20210919083609&isPremium=y&SearchText=max485+module) 
+* An old ethernet cable with RJ45 connector you are happy to cut open
+
+
+## ESP32 D1 MINI <-> MAX485 module
+
+![This one worked for me](../images/max485_module.jpg)
+
+It's powered from `+5V` from ESP32 module, and wired as following:
+
+
+- `DI` -> `IO17` / `GPIO17` / `TX2`
+- `RO` -> `IO16` / `GPIO16` / `RX2`
+- `DE` and `RE` are interconnected with a jumper and then connected to pin  `TCK` / `GPIO13`
+- `VCC` to `+3.3V` / `3V3` on ESP32
+
+
+![ESP32 D1 MINI](../images/esp32_d1_mini_pins.png)
+
+## MAX485 module <-> EPEVER CONTROLLER (RJ45)
+
+Cut open your ethernet cable and split out pin 3, 5, 7 (B, A, GND). Refer to [Tracer Modbus PDF](../docs/1733_modbus_protocol.pdf) for additional info.
+
+Connect cables as follows:
+- Ethernet green, pin `5` -> `A`
+- Ethernet blue, pin `3` -> `B`
+- Ethernet brown, pin `7` -> `GND` on module **and** EPS32 `GND` pin
+		- -> to prevent ground loops - **important!**
+- **DON' T** use pin `1` or `2` to feed the ESP8266 (they supply 7,5/5V - 50mA maximum)
+
+![EPEVER RJ485 SPEC](../images/epever_rj45_specs.png)
+
+## BASE SW CONFIGURATION
+
+Edits required on *src/config.h*:
+- `#define BOARD_ST_SERIAL_PIN_MAPPING_RX 16`
+- `#define BOARD_ST_SERIAL_PIN_MAPPING_TX 17`
+- Uncomment `#define USE_SERIAL_MAX485`
+- `#define MAX485_DE 13`
+- `#define MAX485_RE_NEG 13`
+
+Edit on *platformio.ini* (Platformio only):
+- `platformio.default_envs = wemos_d1_mini32` (usb/serial fw flash) or `platformio.default_envs = wemos_d1_mini32_ota` (ota fw flash)
+
+You may need to make more changes according to your needs (ntp syn/led status/ data to monitor ...).
+
+