3.2 KiB
Galileo Specific Examples
This directory contains galileo-specific example applications to illustrate how to use galileo APIs.
In order to build a application, you should set the EXAMPLE environment variable to the name of the application you want to build. For instance, if you want to build gpio-output application, run the following command:
$ make TARGET=galileo EXAMPLE=gpio-output
The corresponding EXAMPLE variable setting for each application is listed to the right of its heading.
GPIO
GPIO Output (EXAMPLE=gpio-output)
This application shows how to use the GPIO driver APIs to manipulate output pins. This application sets the GPIO 5 pin as output pin and toggles its state at every half second.
For a visual effect, you should wire shield pin IO2 to a led in a protoboard. Once the application is running, you should see a blinking LED.
GPIO Input (EXAMPLE=gpio-input)
This application shows how to use the GPIO driver APIs to manipulate input pins. This application uses default galileo pinmux initialization and sets the GPIO 5 (shield pin IO2) as output pin and GPIO 6 (shield pin IO3) as input. A jumper should be used to connect the two pins. The application toggles the output pin state at every half second and checks the value on input pin.
GPIO Interrupt (EXAMPLE=gpio-interrupt)
This application shows how to use the GPIO driver APIs to manipulate interrupt pins. This application uses default galileo pinmux initialization and sets the GPIO 5 (shield pin IO2) as output pin and GPIO 6 (shield pin IO3) as interrupt. A jumper should be used to connect the two pins. It toggles the output pin stat at every half second in order to emulate an interrupt. This triggers an interrupt and the application callback is called. You can confirm that though the UART output.
I2C
I2C LSM9DS0 (EXAMPLE=i2c-LSM9DS0)
This application shows how to use I2C driver APIs to configure I2C Master controller and communicate with an LSM9DS0 sensor if one has been connected as described below. At every 5 seconds, the application reads the "who am I" register from gyroscope sensor and prints if the register value matches the expected value described in the spec [1].
According to the sensor spec, to read the value in "who am I" register, we should first perform an i2c write operation to select the register we want to read from and then we perform the i2c read operation to actually read the register contents.
The wiring setup is as follows (left column from Galileo and right column from LSM9DS0):
- 3.3v and Vin
- GND and GND
- GND and SDOG
- 3.3v and CSG
- SDA and SDA
- SCL and SCL
I2C Callbacks (EXAMPLE=i2c-callbacks)
This application is very similar to the previous one in that it also shows how to use I2C callback functionality, but it can be run without attaching any additional sensors to the platform since it simply communicates with a built-in PWM controller.
Every five seconds, the application reads the current value of the MODE1 register, which should have previously been initialized to the value 0x20. The test verifies that this expected value is returned by the read.
References
[1] http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00087365.pdf