IoT Expansion Cards Digital Outputs

Now that you've decided to connect to your IoT Expansion board via GPIO, you'll need to:

1. Take a look at the IoT Expansion Board pin map and decide which pin you'll use.
2. Wire up the pin.
3. Configure the pin via the GPIO Service in Octave.

This tutorial describes how to configure and set the value of an output pin on an IoT Expansion Board installed in a mangOH Red, and verify that voltage has been set.

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Note

For this tutorial you will need a multimeter.

Locating the Appropriate Pin Map

Review the IoT Expansion Board pin map and identify the output pin you would like to use.

Configuring a Digit Output

The subsections below describe how to add, configure, and verify a GPIO output on your IoT Expansion Board.

Adding a GPIO Output

Follow the steps below to configure a digital output pin:

1. Navigate to Device > Services, locate the GPIO section, and click Configure.
2. Locate the Add pin section.
3. Click the Pin drop down and select a GPIO pin (e.g. IOT0_GPIO4). Note the expected voltage indicated for the pin which will 1800mV.
4. (Optional) Change the name in Resource to a more descriptive name.
5. Set the Direction to Output.
6. Click Add. The configured output pin appears in the list of GPIO Services.

Setting the Output Value

Follow the steps below to set the value for the digital output pin:

1. Navigate to Device > Resources.
2. Locate and expand io.
3. Locate and expand the resource corresponding to the output pin configured in the previous section (e.g. IOT0_GPIO4/).
4. Click the Configured value column for the enable property and set the property to enabled.

The GPIO pin should now be producing a voltage of 1800mV.

Testing the Output

Follow the steps below to verify that the GPIO pin is outputting voltage.

1. Configure your multimeter to measure voltage levels up to 1.8 VDC.
2. Place the ground probe of the multimeter onto a GPIO ground pin (e.g. Pin 38).
3. Place the positive probe of the multimeter onto the GPIO output pin configured in the previous sections.
4. Verify that the voltage from the GPIO pin matches that defined for the resource (1.8V).