Configuring Reference to an ADC in PSoC1

Question: What are the different reference voltages that can be selected for an ADC measurement?  Is it possible to configure an ADC to take an external reference?

 

Answer:

The reference to an ADC (and other analog sections) may be selected using the "Ref Mux" parameter in the Global Resources.

Following are the various reference settings available in a PSoC with full function Analog blocks.

1.       (Vcc/2)+/- bandgap

2.       (VCC/2) +/- Vcc/2

3.       Bandgap +/- Bandgap

4.       (1.6 Bandgap) +/- (1.6 Bandgap)

5.       (2*Bandgap) +/- Bandgap

6.       (2*Bandgap) +/- P2[6]

7.       P2[4] +/- Bandgap

8.       P2[4] +/- P2[6]

Using options 7 and 8, an external voltage source may be used as AGND or Reference.

Note: The Reference selected using the RefMux parameter is common to all the analog blocks.