MCBXC866: ADC DOES NOT DELIVER PROPER VALUES

Information in this article applies to:

• MCBXC866 mini Evaluation Boards version 1

QUESTION

I have connected a signal to AN0 (P2.0) and my application starts the analog/digital converter periodically, but the values do not reflect the analog input voltage. Why?

ANSWER

The analog reference voltage pin VAREF (pin 25) of the XC866 controller is not connected to any reference voltage on the MCB-XC866 mini. You need to connect the pin VAREF to VDDP or to a more precise reference voltage if you want to use the analog-digital converter. These pins are both available at the connector.

Last Reviewed: Wednesday, January 10, 2007