# I2C BB

I2C bitbang gpio driver using gpio_sys gpio driver

## Installation

```shell
make install
```

Installs `libi2c_bb.a` and `libi2c_bb.so` in the directory `$(PREFIX)/lib/`. It also installs the include header file `i2c.h` in the directory `$(PREFIX)/include/i2c_bb/`. The default value for `PREFIX` is: `PREFIX=usr`. To use another location for installation changing the value of the `PREFIX` variable is needed. E.g.:

```shell
PREFIX=/usr/local/ make install
```

## Uninstallation

```shell
make install
```

Removes the files installed with the `install` make target.  
> **NOTE:** If `PREFIX` variable was changed during installation process the same value needs to be set for uninstallation. E.g.:

```shell
PREFIX=/usr/local/ make install
```

## Example

```C
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <stdbool.h>

#include <i2c_bb/i2c.h>

#define I2C_SLAVE_ADDR  0x48
#define BUFFER_SIZE     3

static const struct gpio_sys gpio_sda = {
    .pin = 4,
    .direction = 0, // out
};

static const struct gpio_sys gpio_scl = {
    .pin = 24,
    .direction = 0, // out
};

const static struct i2c_bb i2c_dev = {
    .sda = &gpio_sda,
    .scl = &gpio_scl,
};

int main(void)
{
    int res;
    char buffer[BUFFER_SIZE]

    openlog("i2c_bb", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);

    res = i2c_open(&i2c_dev);
    if(res != EXIT_SUCCESS) {
        syslog(LOG_ERR, "Unable to open i2c device.\n");
        return res;
    }

    buffer[0] = 0x01;
    buffer[1] = 0xc1;
    buffer[2] = 0x87;

    // Write to register address 0x01 value 0xc187:
    i2c_write(&i2c_dev, I2C_SLAVE_ADDR, buffer, BUFFER_SIZE);

    buffer[0] = 0x00;

    // Set register address 0x00:
    i2c_write(&i2c_dev, addr, buffer, 1);

    // Read from register 0x00 two bytes:
    i2c_read(&i2c_dev, I2C_SLAVE_ADDR, buffer, 2);

    i2c_close(&i2c_dev);

    return EXIT_SUCCESS;
}
```

## Additional make targets

| Target          | Meaning                                                     |
| --------------- | ----------------------------------------------------------- |
| all             | Build the code, assemble the static and shared library.     |
| install         | Install the libraries and necessary include header files.   |
| uninstall       | Uninstall the libraries and necessary include header files. |
| clean           | Clean up build artifacts.                                   |
| distclean       | Remove all folders created during any build step.           |
| build_unit_test | Build the unit tests.                                       |
| exec_unit_test  | Execute the unit tests.                                     |
| coverage        | Determine code coverage of the unit tests.                  |
| check           | Static code analysis (cppcheck).                            |