Nuvotone 8 Bit MCU W79E2051

[swapan]

Hi. Recently I saw a control circuit of Automatic voltage stabiliser which uses Nuvoton W79E251 MCU. On scrutiny of datasheet, it is noticed that the said MCU has no ADC module. No external ADC chip has been used in the circuit. Yet the 7-segment display shows the voltage perfectly. Sample of output voltage is coupled only to analogue comparator module of the MCU. Is it possible to derive data for display of voltage without ADC module?

 

[andre_luis]

Yes, you cam make your own A/D converter, and it's not too dificult to understand. With a constant current source and a small capacitor, you can generate a saw teeth waveform, which can be used to compare with measured signal. The time elapsed to reach the same value is proportional to the voltage.

 

[swapan]

Thanks. Getting hints from you, I have goggled and got a conception about the matter. I was very curious - how the A/D conversion has been done without ADC module.Now my curiosity is over.