# C example for xtensa esp32 architecture

Presented here is a straightforward C example utilizing Martos.

It has empty setup function.
Additionally, within the loop function, the counter value is incremented fifty times.

## How to install dependencies

For comprehensive guidance on installing the necessary dependencies for developing applications targeting the Xtensa ESP32 architecture, 
please refer to [the official website](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/index.html#manual-installation). 
Below is an illustrative example demonstrating the installation of building toolchains on a Linux (Ubuntu/Debian):
```
sudo apt-get install -y git wget flex bison gperf python3 python3-pip python3-venv cmake ninja-build ccache libffi-dev libssl-dev dfu-util libusb-1.0-0 make
mkdir -p ~/esp
cd ~/esp
git clone -b v5.2 --recursive https://github.com/espressif/esp-idf.git
cd ~/esp/esp-idf
./install.sh esp32
```

## Before building the example

Before proceeding with building the example, it is essential to obtain the Martos C static library 
and [link it](https://github.com/IvanArkhipov1999/Martos/blob/main/examples/c-examples/xtensa-esp32/Makefile#L26) with the example code.

There are multiple avenues through which you can acquire the Martos C static library:
1. [From release artifacts.](https://github.com/IvanArkhipov1999/Martos/releases)
2. [From ci artifacts.](https://github.com/IvanArkhipov1999/Martos/actions)
3. [To build the Martos C static library independently.](https://github.com/IvanArkhipov1999/Martos/tree/main/c-library/xtensa-esp32)


## How to build the example

For a thorough guide on developing projects for the Xtensa ESP32 architecture across various operating systems, 
we recommend consulting [the official website](https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/index.html#build-your-first-project).
Below, you will find an illustrative example showcasing the building process on a Linux system (Ubuntu/Debian):
```
. $HOME/esp/esp-idf/export.sh
make
```

## How to run the example

To upload the program, you need to format it for the ESP32 and then store it in the SPI Flash chip connected to the actual ESP32 within the module. 
You can do that with Espressif’s esptool utility. 
To format the ELF file into a binary image:
```
esptool.py --chip esp32 elf2image --flash_mode="dio" --flash_freq "40m" --flash_size "4MB" -o main.bin main.elf
```

To flash a binary image to Flash address 0x1000 (where the ESP32 expects a ‘bootloader’ to be located):
```
esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 115200 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 40m --flash_size detect 0x1000 main.bin
```

To run the program:
```
esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 115200 --before default_reset --after hard_reset run
```

Note that you might need to specify a different port, depending on which system resource your ESP32 is connected to.