WeMos D1 mini pro

The D1 mini Pro is a mini wifi board based on ESP-8266EX.

ESP8266EX integrates the ultra-low power Tensilica L106 cache-less, no hardware divider, 32-bit micro controller (MCU), which is the smallest of the Xtensa RISC controllers.

See WeMos official web site for full documentation.

Features:

• 11 digital input/output pins
• Interrupt/pwm/I2C/one-wire
• 1 analog input(3.2V max input)
• 16M bytes(128M bit) Flash
• External antenna connector
• Built-in ceramic antenna
• New CP2104 USB-TO-UART IC
• Same size as D1 mini, but more light

Technical specs
Microcontroller	ESP-8266EX
Operating Voltage	3.3V
Digital I/O Pins	11
Analog Input Pins	1(Max input: 3.2V)
Clock Speed	80MHz/160MHz
Flash	16M bytes
Length	34.2mm
Width	25.6mm
Weight	2.5g

Pin Mapping

Thanks to HERON'S BLOG, the following table maps the Wemos D1 mini's pins to ESP8266 and Arduino pin numbers.

Pin	Function	ESP-8266	Arduino	Arduino IDE
TX	IO, Serial TX	GPIO1,TXD	D1	1
RX	IO, Serial RX	GPIO2,RXD	D3	3
A0	Analog input, max 3.3V input	ADC	A0	A0
D0	IO	GPIO16	D16	16
D1	IO, SCL	GPIO5	D5	5
D2	IO, SDA	GPIO4	D4	4
D3	IO, 10k Pull-up	GPIO0	D0	0
D4	IO, 10k Pull-up, BUILTIN_LED	GPIO2	D2	2
D5	IO, SCK	GPIO14	D14	14
D6	IO, MISO	GPIO12	D12	12
D7	IO, MOSI	GPIO13	D13	13
D8	IO, 10k Pull-down, SS	GPIO15	D15	15
G	Ground	GND	GND
5V	5V	-	5V
3V3	3.3V	VCC	3.3V
RST	Reset	RST	RESET

All of the IO pins have interrupt/pwm/I2C/one-wire support except D0.

All of the IO pins run at 3.3V.

PlatformIO IDE

I choose PlatformIO IDE as integrated development environment.

It is a cross-platform build system running on top of GitHub's Atom text editor.

The repository directory structure complies with the need to maintain both the libraries and the projects source code.

Repository directory structure

+--WeMosD1
|  +--libraries
|  |  +--_Lib_stub_
|  |     +--src
|  |        +- _Lib_stub_.c
|  |        +- _Lib_stub_.h
|  +--projects
|  |  +--_App_stub_
|  |  |  +--lib
|  |  |  |  +- readme.txt
|  |  |  +--src
|  |  |  |  +- main.cpp
|  |  |  +- _App_stub_.pro
|  |  |  +- platformio.ini
|  |  +- platformio.ini.template

./libraries

Extra libraries directories root where PlatformIO Library Dependency Finder (LDF) will look for dependencies.

Edit the platformio.ini project configuration file and set lib_extra_dirs LDF option to libraries relative path (see below).

./libraries/_Lib_stub_

_Lib_stub_ library directory root.

./libraries/_Lib_stub_/src

Source code of _Lib_stub_ library.

./projects

PlatformIO projects directories root.

./projects/platformio.ini.template

PlatformIO project configuration file template.

Update the project specific platformio.ini file with its content.

./projects/_App_stub_

_App_stub_ project directory root.

./projects/_App_stub_/src

Source code of the project.

./projects/_App_stub_/lib

This directory can be used to store the project specific (private) libraries.

More details are located in lib/readme.txt file.

./projects/_App_stub_/_App_stub_.pro [optional]

Qt Creator project configuration file.

./projects/_App_stub_/platformio.ini

_App_stub_ project configuration file.

This file is created any time that PlatformIO initializes a project.

Add the following lines to the [env:d1_mini] section:

; extra directory where Library Dependency Finder (LDF) will look for dependencies.
lib_extra_dirs = ../../libraries

; uploader connection speed (baud rate) used to send firmware to board.
upload_speed = 921600

See platformio.ini.template.

PlatformIO IDE Setup

Launch Atom editor and add a project folder (i.e. WeMosD1):

File > "Add Project Folder..." > /path/to/WeMosD1

Create the directories:

./libraries
./libraries/_Lib_stub_
./projects

Create a PlatformIO project:

PlatformIO > "Initialize or Update PlatformIO Project"

The PlatformIO: Initialize or Update PlatformIO Project dialog should result:

Selected board:
WeMos D1 R2 & mini

Choose the directory:
/absolute/path/to/WeMosD1/projects/_App_stub_

Edit the platformio.ini project configuration file and set lib_extra_dirs LDF option to libraries relative path (see above).

PlatformIO integration with Qt Creator

See PlatformIO Qt Creator official page for more detailed information.

Fist of all, add the folder where is located platformio program to system PATH.

Choose board ID using platformio boards or Embedded Boards Explorer and generate project via platformio init --ide command.

# Generate project for WeMos D1 Mini
platformio init --ide qtcreator --board d1_mini

The project is generated under the current directory. You can specify another project directory via platformio init -d %PATH_TO_THE_PROJECT_DIR% command.

Among other stuff, platformio generates the platformio.pro. You are free to rename it as your preferences, such as yourProject.pro.

Import project via File > Open File or Project and select platformio.pro from the folder where is located Project Configuration File platformio.ini.

Select default desktop kit and click on Configure Project (Projects mode, left panel).

Set General > Build directory to the project directory where is located Project Configuration File platformio.ini.

Remove all items from Build Steps, click on Build Steps > Add Build Step > Custom Process Step and set:

• Command: platformio
• Arguments: -f -c qtcreator run
• Working directory: %{buildDir}

Remove all items from Clean Steps, click on Clean Steps > Add Clean Step > Custom Process Step and set:

• Command: platformio
• Arguments: -f -c qtcreator run --target clean
• Working directory: %{buildDir}

Warning

The libraries which are added, installed or used in the project after generating process wont be reflected in IDE. To fix it you need to reinitialize project using platformio init (repeat it).

Conclusion

Build the project with shortcut Ctrl+Shift+B or using Menu: Build > Build All.

Useful commands

# process/build project from the current directory
platformio run

# upload firmware to embedded board
platformio run --target upload
# or
platformio run -t upload

# clean project (remove compiled files)
platformio run --target clean

# additional information
platformio run --help