how to measure the coin cell battey voltage in real

[MARTIN FR]

Hello Everyone,

I am trying to measure the (3v)battery voltage by having proximity example as reference but intially it is showing 100percent later it is going to 13(percent) voltage approxmiatelry (after 120seconds) i dont understand why it is happening like this can anyone suggest me some possible ways to measure out by using multimeter how much voltage available on ADC pin ? so that i can able to make some idea about the battery level measurement§?

[Einar Thorsrud]

You are just printing random data. This is snippet from your main() function shows that you are declaring the variables adc_value and batt_lvl_in_milli_volts and printing them without ever initializing them:

 int adc_value,batt_lvl_in_milli_volts;
 uart_config();
 printf("initialization");
 printf("%d adc_value\n",  adc_value); // out ADC result
 printf("%d\r\n", batt_lvl_in_milli_volts ); // out ADC result

You have the same variable names defined in ADC_IRQHandler(), but these are completely independent variables though they have the same names. (The variables are declared in separate functions, so they will have separate scopes, and this will not generate any warnings. You should get warnings for using a uninitialized variable, though, depending on how your compiler is configured).

[MARTIN FR]

so what is the other possible ways to do the correct measurement with dependent variable can you suggest meplease?

[Einar Thorsrud]

The point is that you have to make sure adc_value and batt_lvl_in_milli_volts has a value when you print them. Why not print them in ADC_IRQHandler()? Then they would be printed every time a sample is collected.

[MARTIN FR]

yes i made those statements in adc_irq ahndler but nothing gets executed it reamins only upto initialization part

[MARTIN FR]

Hello Einar as i followed your suggestion i got the adc_result as 57 and int he register R4 it is showing 3A can you please tell me what is the reason for that strange value?