UNO+WiFi R3 ATmega328P+ESP8266 (32Mb memory), USB-TTL CH340G. Compatible for Arduino Uno, NodeMCU, WeMos ESP8266

Really a nice, cost effective, board for both ATmega328P and ESP8266 development, with easy flashing for either microprocessor. However, you need a few details not provided with the board in order to effectively use this board. You can find a bit more information on the manufacturer's (RobotDyn) website, but I'll try to include the most important details in this review.The most critical details are how the various components on the board are connected together. Most of the connections are serial interfaces controlled by the set of switches included on the board (see picture), but for me the simple table included in the silkscreen didn't give me quite enough information. Here is what I have worked out:1. To program the ATmega328P, flip switches 3 and 4 to ON and the others off. This will bridge the RX and TX pins of the CH340G UART (pins 2 and 3) to the ATmega's RX and TX pins (Digital 0 and 1), allowing you to program the ATmega using the Arduino IDE using the Arduino/Genuino UNO board type, and supporting the Serial Monitor in the IDE. (The on-board table lists this as [USB+MCU]).2. To program the ESP8266, flip switches 5, 6, and 7 to ON (and the others off). This will bridge the CH340G RX and TX pins to the ESP's TX and RX pins (switches 5 and 6), and connect the ESP's GPIO0 to GND to set the ESP into firmware write mode. (The on-board table lists this as [USB+ESP] and [GND-GPIO0]).3. To USE the ESP8266, and communicate with it using the CH340G, set switches 5 and 6 to ON. If you still have the NodeMCU firmware on the ESP you can issue AT commands to the ESP through the UART using a serial terminal emulator or even the Arduino IDE's Serial Monitor. (The on-board table lists this as [USB+ESP]).4. To use the ATmega to control the ESP flip switches 1 and 2 ON. This connects the ATmega's TX and RX pins to the ESP's RX and TX pins, allowing your Arduino code to use "Serial.println()" and other Serial methods to communicate with the ESP. Be aware that this mode disconnects the CH340G UART from both microprocessors, so you will have to either wire up another set of pins to work with the SoftwareSerial library for debugging, etc., or connect some other display device for output. (The on-board table lists this as [MCU+WiFi]).Once I worked out these details the table printed on the board made much more sense to me.One other point, the 32Mb memory chip (Winbond 25Q32FVSIG) is only connected to the ESP8266. It is used to provide the ESP's SPIFFS file system. If you want to use it to store data used by the ATmega you will need to write code for both microprocessors to send read/write requests from the ATmega to the ESP, with the ESP doing the work to read and write the data to the Flash memory.