Question: How do I bring out an internal reference voltage to an external pin?
Answer: The internal reference can be brought out using the Vref component and an Op-amp configured as a buffer. For example, let us bring out the Vdda/2 signal to an output pin as Analog Ground.
1. Drag and drop the Vref component from the System category. Vref can be configured to provide Vssa, 0.256V, 1.024V, Vdda/2 and Vdda. Select Vdda/2.
2. Drag and drop an OpAmp component from the Amplifiers section. Double click on the component and in the Basic Tab, select "Follower" for the Mode parameter. This will configure the OpAmp into a unity gain buffer.
3. Drag and drop an Analog pin from the System category. Rename it to Agnd_Out (or any other convenient name)
4. Connect the input of the OpAmp to Vref and the output of the OpAmp to the Analog pin.
5. Open the <Project_Name>.cydwr file. Select the desired pin for the Agnd_Out pin.
6. In main.c, call the OpAmp_1_Start() function to start the buffer. The AGND signal is now available in the selected pin.