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In order to display the temperature in three integral and one fractional digits using the LCD over the range of the temperature sensor and updating the display data five times per second, what critical data should I obtain? I have a successive approximation ADC and the e clock of the MCU is 24 MHz. I have used a scaling circuit to connect the sensor to MCU. The sensor has a 10 mv/C voltage slope between its output voltage and temperature. I do not know how to calculate the temperature from the vout that I see.

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From the information you provided, the answer is very simple. If the sensor has an output of 10 mv/C, then the indicated temperature is found by dividing the sensor output (in millivolts) by 10. For example, if the sensor output is 100 mv, then the temperature is 10C. You may need to scale your ADC output to obtain the sensor output in millivolts depending on the ADC reference voltage and resolution.

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  • \$\begingroup\$ In the text book it says that " to convert the A/D conversion result to the corresponding temperature we need to divide the conversion result by 6.2. I honestly don't know where this number comes from \$\endgroup\$ – Jack Oct 3 '15 at 1:03
  • \$\begingroup\$ The range of the voltage connected to AN7 pin is between 9 and 5. \$\endgroup\$ – Jack Oct 3 '15 at 1:04
  • \$\begingroup\$ I think The A/D conversion results should be converted to the actual analog voltages \$\endgroup\$ – Jack Oct 3 '15 at 1:05
  • \$\begingroup\$ I had to use scalers to feed the signal to the MCU so it won't be a simple dividing by 10 I guess. \$\endgroup\$ – Jack Oct 3 '15 at 1:07

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