Wemos LOLIN D32 - ESP32 WROOM-32 + 4MB flash

The LOLIN D32 IoT development platform with ESP32 and 4MB of Flash

The Wemos LOLIN D32 is the Wemos platform succeeding the D1 Mini based on ESP8266.

With the D32, you have an ESP32 (WROOM-32) with 4MB of Flash memory, ideal for projects using Arduino IDE or MicroPython. The D2 is also delivered with MicroPython preloaded on the board.

With this board, you have:

• an official Expressif WROOM-32 (ESP32) module clocked at 240 Mhz
• no less than 22 inputs outputs
• 6 analog inputs (ADC, 3.3V)
• 2 real analog outputs (DAC, 3.3V)
• A 3.7V Lipo battery charger (500mA max)
• 4 MB of Flash
• A MicroUSB connector with USB-Serial converter (CH340C).
• User LED on IO 5 (lit in LOW level)

The advantage of this board is that it also has an automatic activation of the bootloader. No need to press the Reset button to upload a soft from Arduino IDE.

Lipo charger

The board also has a JST PH connector for the connection of a Lipo Battery (see  our range of batteries). Recharging the battery is supported by a TP4054, an LED indicates when the battery is charging (when the board is connected via USB).
Finally, it is possible to have an indication of the charge on the IO35 since the battery is connected to it via a voltage divider bridge 100 KOhms - 100 KOhms. The battery voltage is therefore halved.

Note that the platform is primarily powered by USB if it is connected (it is the battery charge which is privileged in this case).

Logic level and power

The board operates in 3.3V logic, voltage regulated by the ME6211 regulator capable of producing a maximum current of 500mA.

However, the board is designed to be powered in 5.0V via USB (or a Lipo battery)

The board can therefore be powered:

• Via USB (thus 5V, priority on the battery)
• Via a battery on the JST connector (or connected directly to VBAT)
• Via VBUS by applying a voltage of 5V.
  Be careful not to leave the USB connected at the same time to avoid the flow of current between the USB and your power supply on VBUS.
• Via 3.3V by injecting a 3.3V voltage directly after the regulator.
  This method isn't recommended because it presents a high risk of error.

Note that as designed, it's not possible to deactivate the voltage regulator since its EN pins are not accessible in breakout.
On the other hand, the ESP32 can be deactivated by placing its EN pin to the ground!

Technical specifications

• Microcontroller: WOORM-32 (ESP32)
• Operating voltage: 3.3V
• TSupply voltage: 5V via microUSB, VBAT via 3.7V Lipo battery
• Digital inputs/outputs: 22 pins, 3.3V max.
• Analog input: 2
  
  • Max Voltage: 3.2V
  • True 3.3V input.
• BUS:
  
  • SPI materiel
  • I2C
• Analog output (2 DAC)
• Clock speed: 240 MHz (max)
• External Flash Memory: 4 MBytes (4 MB)
• Internal voltage regulator: ME6211 5V to 3.3V, 500mA max.
  200 to 250mA available for projects.
• LED on IO5 (reverse logic)
• Length: 57.00mm
• Width: 25.4mm
• Weight: 6.9g

Content

The Wemos LOLIN D32 + a set of male connectors that you can weld on your board.

Wemos pinout

See product images

Ressources

• Wemos LOLIN D32 Wiki page (English)
  Contains technical information, code, driver, example, etc.
• Datasheet of ME6211 voltage regulator (pdf)
• Datasheet of USB to CH340G Series (pdf, from this product page of SparkFun)