Host Emulator
The latest versions of Sming allow most of components of the library and the sample applications to be compiled on a Linux/Windows host system and be tested before uploading them to the microcontroller.
If you want to try it we have an interactive tutorial that can be run directly from your browser.
See Getting Started for installation details.
The following sections provide more background detail.
Requirements (Linux)
Modern Linux distribution
Most popular modern distributions should be fine. At the moment we develop only with Ubuntu 16.04 and 18.04.
C/C++ 32 bit compiler and libraries
The latest versions of Sming require GCC version 8 or newer. If your OS is 64 bit then 32 bit C/C++ compiler and libraries are also required. Here’s a summary of how to do this:
sudo apt update
sudo apt install gcc-9 g++-9
# For 64-bit systems
sudo apt install gcc-9-multilib g++-9-multilib
# Set GCC 9 as default
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 60 --slave /usr/bin/g++ g++ /usr/bin/g++-9
The current version is GCC 9.3.0.
CMake 3.8 or newer
For the compilation of LWIP CMake
version 3.8 or newer is required.
In order to get newer CMake version under Ubuntu 16.04, do this:
cd /tmp
wget https://github.com/Kitware/CMake/releases/download/v3.14.4/cmake-3.14.4-Linux-x86_64.sh
sudo mkdir /opt/cmake
sudo sh cmake-3.14.4-Linux-x86_64.sh --prefix=/opt/cmake
sudo mv /usr/bin/cmake /usr/bin/cmake.orig
sudo ln -s /opt/cmake/bin/cmake /usr/bin/cmake
Requirements (Windows)
For Windows, make sure your MinGW
distro is up to date.
The current version is GCC 8.2.0.
Note
If you don’t already have MinGW installed, see Windows Installation.
Compilation
Environment variables
SMING_ARCH
must be set to use Host
as the desired architecture:
export SMING_ARCH=Host
Debug Build
If you plan to use a debugger make sure to set ENABLE_GDB
and (optionally)
ENABLE_LWIPDEBUG
before compiling the code:
export ENABLE_GDB=1
export ENABLE_LWIPDEBUG=1 # <!-- this will compile also LWIP with debug symbols
Initial Clean-up
Make sure that you are working on a clean source code tree. The following commands may help:
cd $SMING_HOME
make dist-clean
Sample compilation
Compile a sample as usual:
cd $SMING_HOME/../samples/Basic_Blink
make
Adapting existing code
You may need to modify your existing applications to work with the
emulator. Architecture-specific code should be moved into separate code
modules. Code that is specific to the ESP8266 may be conditionally
compiled using #ifdef ARCH_ESP8266
. Similarly, you can check if the
code is compiled for the emulator using #ifdef ARCH_HOST
.
Running on the host
Once the sample is compiled, initialise the Virtual Flasher:
make flash
If enabled, this will also create a SPIFFS file system and write it to flash.
To run the application, do this:
make run
Networking
Support is provided via TAP network interface (a virtual network layer
operating at the ethernet frame level). A TAP interface must be created
first, and requires root privilege. You can use the
Sming/Arch/Host/Tools/setup-network-linux.sh
. Here is the manual approach:
sudo ip tuntap add dev tap0 mode tap user `whoami`
sudo ip a a dev tap0 192.168.13.1/24
sudo ip link set tap0 up
# The following lines are needed if you plan to access Internet
sudo sysctl net.ipv4.ip_forward=1
sudo sysctl net.ipv6.conf.default.forwarding=1
sudo sysctl net.ipv6.conf.all.forwarding=1
export INTERNET_IF=wlan0 # <!--- Make sure to replace wlan0 with the network interface connected to Internet
sudo iptables -t nat -A POSTROUTING -o $INTERNET_IF -j MASQUERADE
sudo iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i tap0 -o $INTERNET_IF -j ACCEPT
This creates the tap0
interface. The emulator will automatically
select the first tap
interface found. To override this, use the
--ifname
option.
You can list available network interfaces thus:
ip link
Troubleshooting
Issue 1: fatal error: sys/cdefs.h: No such file or directory
Make sure to install the 32bit version of the GNU C and C++ compiler, development package and libraries.
Issue 2: fatal error: bits/c++config.h: No such file or directory
Make sure to install the 32bit version of the GNU C and C++ compiler, development package and libraries.