An apparatus for sensing a touch to a substrate and determining a location thereof, comprising: a mixed signal device comprising a digital processor and first and second outputs (122, 126) operable to be switched into high impedance and first and second analog inputs (120, 124) and further comprising a capacitive time measurement unit comprising a constant current source, a timing capacitor, and an analog-to-digital converter; a serpentine transmission line fabricated on the substrate, wherein a first end of the serpentine transmission line is connected to the first analog input and coupled via a first resistor with the first digital output and a second end of the serpentine transmission line is connected to the second analog input and coupled via a second resistor with the second digital output; wherein for performing a first measurement, the mixed signal device is configured to switch the second output into high impedance and generate a first pulse at the first output, and to control the constant current source to start charging the timing capacitor until a first return pulse is received at the first analog input, whereupon a first voltage charge on the timing capacitor is sampled by the ADC and converted to a first digital value; and wherein for subsequently performing a second measurement, the mixed signal device is configured to switch the first output into high impedance and generate a first pulse at the second output, and to control the constant current source to start charging the timing capacitor until a second return pulse is received at the second analog input, whereupon a second voltage charge on the timing capacitor is sampled by the ADC and converted to a second digital value; and wherein the digital processor is operable to determine a touch location from said first and second digital value. a mixed signal device comprising a digital processor and first and second outputs (122, 126) operable to be switched into high impedance and first and second analog inputs (120, 124) and further comprising a capacitive time measurement unit comprising a constant current source, a timing capacitor, and an analog-to-digital converter; a serpentine transmission line fabricated on the substrate, wherein a first end of the serpentine transmission line is connected to the first analog input and coupled via a first resistor with the first digital output and a second end of the serpentine transmission line is connected to the second analog input and coupled via a second resistor with the second digital output; wherein for performing a first measurement, the mixed signal device is configured to switch the second output into high impedance and generate a first pulse at the first output, and to control the constant current source to start charging the timing capacitor until a first return pulse is received at the first analog input, whereupon a first voltage charge on the timing capacitor is sampled by the ADC and converted to a first digital value; and wherein for subsequently performing a second measurement, the mixed signal device is configured to switch the first output into high impedance and generate a first pulse at the second output, and to control the constant current source to start charging the timing capacitor until a second return pulse is received at the second analog input, whereupon a second voltage charge on the timing capacitor is sampled by the ADC and converted to a second digital value; and wherein the digital processor is operable to determine a touch location from said first and second digital value.