Connect the USB cable to the board. You will get a new CDC serial port. You can check which one you get with
Normally you get /dev/ttyUSB0 or /dev/ttyUSB1 or the like. To make them usable for you you should add yourself to the dialout group
addgroup user dialout
where “user” is your username. You can also do this manually in the /etc/group file or
chmod a+rw /dev/ttyUSB0
if you like brute force.
Loading code to the ESP8266
The ESP8266 CPU can be booted in three different ways:
- Flash Mode: default booting mode. Firmware is read and executed from the flash memory. Pins need to be set to: GPIO15=0, GPIO0=0, GPIO2=1
- UART Mode: used to program our board (through a Serial-to-Usb adapter). Pins need to be set to: GPIO15=0, GPIO0=1, GPIO2=1
- SDIO Mode: loads firmware from an SDIO card? Pins need to be set to: GPIO15=1, GPIO0=0/1, GPIO2=0/1
The boot process is described here.
Switching from a mode to another requires to reset the module while the pin states listed is set.
With the nodemcu board and esptool flash uploader all this is handle automatically but if you have another board you must handle this yourself.
You find it here.
sudo git clone https://github.com/pfalcon/esp-open-sdk.git cd esp-open-sdk
apt-get install make unrar autoconf automake libtool libtool-bin gcc g++ gperf flex bison texinfo gawk ncurses-dev libexpat-dev python sed git clone --recursive https://github.com/pfalcon/esp-open-sdk cd esp-open-sdk/ make
echo 'PATH=$PATH:~/development/esp8266/esp-open-sdk/xtensa-lx106-elf/bin' >> ~/.profile echo 'PATH=$PATH:~/development/esp8266/esp-open-sdk/esptool' >> ~/.profile PATH=$PATH:~/development/esp8266/esp-open-sdk/xtensa-lx106-elf/bin PATH=$PATH:~/development/esp8266/esp-open-sdk/esptool
I have installed the toolchain in
so change paths above for your installation folders.
Update it (when updates are available)
make clean git pull git submodule update
Firmware upload tool
pip install esptool
First code (blinky)
You find it here
to build it. Remember that the paths above must have been set. You may get some warnings. No problem.
For your information. If you build from source code should be loaded like this:
That is just what we do here. Upload to your module with
esptool.py --port /dev/ttyUSB1 write_flash 0x00000 blinky-0x00000.bin 0x10000 blinky-0x10000.bin
No need to press any buttons during flashing. It is handled automatically by the USB DTR circuitry.
Now we are ready to do some real work for our VSCP system with the ESP8266. If you rather prefer Arduino this howto may be the one you should go for instead of this one. Life is much simpler in the Arduino world. But the degrees of freedom is better if you do it all by yourself. The penalty for freedom is more problems of course. As always.
Part 2 will follow.