Two variable resistors (RS & RE) and one static resistor (RC) are connected to a high impedance input analog input pin of a micro-controller. The static resistor is connected to ground and the two variable resistors are connected to digital outputs of the micro controller where they can be driven to +V or to ground. By driving RE or RS either high or low in any configuration and sampling the voltage from the resulting voltage divider is it possible to deduce the value of RS, and if so what formula would describe it? The value of the variable resistors is to be considered the same between successive scans.
Not required for the question but RS is assumed to be between 1kΩ and 100kΩ and RE is assumed to between 200Ω and 20kΩ. RC can be any constant.