In the HT47 R-F type MCUs, what is the principle of R-F A/D Converter and how to use it?
Answer One unique feature of the HT47 R-F type MCU is its internal R-F A/D Converter. To utilize this function, the ADCR register should be setup to choose the ADC mode and to select either Timer A or Timer B as a timer or as a counter with which the R or C oscillator input is to be measured. When Timer A (or Timer B) overflows, the user can read the conversion value in Timer B (or Timer A). The principle behind the R-F A/D Conversion is that the RC oscillation frequency is proportional to the R or C value. By comparing the counter values of the RC network formed by variable resistor RT and a high precision reference resistor RS, the user can convert the external physical parameters into a digitized value.
